Cable-entry terminology for clear product specifications.

360-degree screen contact

Full-circumference cable-screen contact

An EMC termination arrangement that contacts the cable braid or foil screen around substantially the full circumference.

Specified on EMC gland drawings, shield-termination instructions and screened-cable installation details.

Confirm screen diameter, exposed length, contact hardware and assembly method; a metal body alone does not establish 360-degree contact.

• IEC↗

6061-T6

6061 aluminium alloy in the T6 temper

6061 is a magnesium-silicon-containing wrought aluminium alloy; T6 identifies solution heat treatment followed by artificial ageing. The alloy number and temper describe different aspects of the material.

Appears in machined gland, connector-shell and enclosure-component material descriptions.

Check product form, thickness, specified mechanical properties and manufacturing history. Welding or later heating can change local properties; 6061-T6 does not imply defect-free machining or zero distortion.

• ISO↗
• ISO↗
• Hydro↗

A1 / A2 gland

A1 and A2 non-armoured cable-gland construction labels

Legacy construction labels for glands on non-armoured cables. A1 usually describes a simple entry arrangement; A2 usually adds an outer-sheath seal and cable retention.

Seen in British-pattern gland catalogues and replacement specifications for unarmoured cables.

Read the exact construction drawing and declared functions. The label alone does not establish an IP rating, retention class or hazardous-area approval.

• BSI↗
• IEC↗

Abrasion resistance

Resistance to material loss by rubbing

A material or surface's resistance to wear caused by contact and relative movement under a stated abrasion test or service condition.

Specified for cable jackets, gland inserts and protective boots.

Compare equivalent test methods, loads and counter-surfaces; hardness alone does not establish abrasion resistance in the intended installation.

• ISO↗
• IEC↗

Absolute / gauge pressure

Vacuum-referenced and ambient-referenced pressure

Absolute pressure is referenced to a perfect vacuum; gauge pressure is referenced to a stated surrounding pressure, usually the local atmosphere.

Used in leak testing, pressure ratings and submerged or evacuated equipment calculations.

Identify the reference and units and use the relevant atmospheric pressure when converting; absolute and gauge values are not interchangeable.

• ISO↗
• ISO↗

Absolute / thermodynamic temperature

Temperature measured from absolute zero

Thermodynamic temperature T is expressed in kelvins. For a temperature t in degrees Celsius, T/K = t/°C + 273.15. A temperature difference of 1 K has the same magnitude as 1 °C.

Used in gas-state, temperature-pressure and thermodynamic calculations.

Use kelvins for absolute-temperature ratios. Celsius readings can be used for temperature differences but not directly in ideal-gas proportionality relations.

• ISO↗

Absorbed dose / dose rate

Absorbed radiation dose and absorbed-dose rate

Absorbed dose is energy imparted by ionizing radiation per unit mass, commonly expressed in gray; absorbed-dose rate is the change in that quantity per unit time.

Used in radiation exposure or sterilization studies of polymers, cables and electrical components.

State dose, rate, radiation type and exposure conditions; total dose and rate are distinct, and retained properties must be assessed for the actual material or assembly.

• ISO↗

Accelerated weathering / aging

Accelerated weathering and accelerated ageing

Weathering tests apply defined light and environmental exposures; broader accelerated ageing uses intensified conditions to study time-dependent changes. Neither automatically gives a universal field-life conversion.

Used in outdoor polymer, seal and cable-material durability programmes.

Verify that the relevant degradation mechanisms and measurements match the intended service; test hours must not be presented as guaranteed service years without a validated model.

• ISO↗
• ISO↗

Acceptance test

Test used for contractual or installation acceptance

A test performed to establish whether delivered equipment or an installation meets specified acceptance requirements for the particular supply or project.

Used in purchase specifications, factory acceptance and site acceptance procedures.

Agree the configuration, method and pass criteria in advance; an acceptance test may have a different purpose and scope from product type qualification.

• IEC↗
• IEC↗

Adaptor

Cable-entry thread adaptor

A threaded accessory that connects a cable gland or fitting to an enclosure entry with a different thread form or size.

Used between glands, conduit fittings, junction boxes, gland plates and equipment entries.

Verify both thread designations, sealing faces, engagement, material, temperature and any ingress or Ex approval scope.

• IEC↗
• IEC↗

AHJ

Authority having jurisdiction

The organization, office or person responsible under the applicable arrangements for enforcing requirements or accepting an installation, equipment or procedure.

Used in electrical-code and installation approval discussions.

Identify the authority and governing requirements for the specific project; supplier advice or certification evidence does not replace the relevant acceptance decision.

• UL Solutions↗
• OSHA↗

Airflow capacity

Airflow through a component under stated conditions

The amount of air passing through a vent or other flow path per unit time at a defined pressure difference and gas condition.

Specified on pressure-equalization vents and enclosure ventilation components.

Compare the same pressure difference, reference conditions and installed area; an airflow number without those conditions does not establish enclosure equalization speed.

• ISO↗
• IEC↗

Allowable load / working load

Permitted load and expected load in service

An allowable load is a load limit established for stated conditions and an identified acceptance basis. Working load is the load expected in the application; the two values serve different purposes.

Used when comparing cable-retention, support or attachment capability with an anticipated mechanical demand.

Check the source of the allowable value, load direction, temperature and duration. Do not substitute ultimate failure load or a different installation configuration.

• IEC↗
• IEC↗
• ISO↗

Aluminium alloy

Aluminium-based engineering alloy

A metal alloy based on aluminium with controlled alloying additions. Wrought and cast grades have different designation systems, and alloy identity is separate from temper and surface treatment.

Used for lightweight entry hardware, connector shells, housings and machined accessories.

Specify the exact alloy, product form, temper, finish and galvanic pairing. A generic aluminium label does not establish strength, corrosion resistance, bonding performance or an approved gland construction.

• ISO↗
• IEC↗

Ampacity

Permitted continuous conductor current under stated conditions

The allowable current a conductor or cable can carry without exceeding relevant temperature or installation limits under specified operating conditions.

Used in cable sizing and electrical installation design.

Check conductor, insulation, ambient conditions, grouping and installation method; nominal area or AWG alone does not establish ampacity.

• IEC↗
• IEC↗

Anisotropy

Direction-dependent material properties

A condition in which a material or component responds differently in different directions, often due to fibre orientation, processing or crystal structure.

Relevant to reinforced gland bodies, moulded housings and layered materials.

Use properties for the loaded direction and account for moulding orientation; a single datasheet value may not describe every direction in the part.

• ISO↗

Anodizing

Electrochemical conversion to an oxide surface

A treatment that develops an oxide layer on a suitable metal, commonly aluminium, with performance depending on process, thickness and sealing.

Used on aluminium enclosures, fittings and mounting parts.

Check the specified finish and treatment of bonding surfaces; an anodized layer can alter electrical continuity and is not a universal corrosion barrier.

• ISO↗

Anti-seize compound

Compound intended to reduce joint seizing

A surface-applied lubricant or separating compound intended to reduce galling, corrosion binding or difficult disassembly of specified metal joints.

Mentioned in maintenance instructions for threaded metal entries and fasteners.

Use only a compatible, permitted compound and torque procedure; avoid contamination of seals, electrical contacts or flamepaths where the instructions restrict it.

• ISO↗
• IEC↗

Anti-short bushing

Insulating anti-short-circuit bushing

An insulating sleeve placed at a cut metallic cable armour end to protect conductor insulation from sharp edges and accidental contact.

Used during termination of certain armoured cable constructions and fittings.

Follow the cable and fitting instructions for bushing requirements. A protective sleeve does not replace a compatible connector, bonding path or correct deburring.

• UL Solutions↗

Applied load factor

Specified multiplier applied to a calculated load

A dimensionless multiplier applied to a baseline load for a defined design case. Its meaning and value come from the project method or applicable requirement, not from multiplication itself.

Used to scale estimated hanging-cable or attached-equipment loads before comparing them with a separately established allowable load.

Document the factor and its basis. It is not a measured retention rating, a material strength or an automatically generated safety factor; avoid applying the same allowance twice.

• ISO↗
• IEC↗

AQL

Acceptance quality limit

An index used to select acceptance-sampling schemes for a continuing series of lots under a specified procedure, rather than a guarantee about every unit.

Used in incoming inspection and contractual lot-sampling plans.

Specify the sampling standard, inspection level and acceptance/rejection rules; AQL does not mean zero defects or a fixed permitted defect count for every lot.

• ISO↗

Arc-fault detection

Detection of electrical arcing faults

A function intended to identify specified arcing conditions from electrical or other signatures so a system can respond according to its protection design.

Used in PV DC arc-protection systems and other defined circuit-protection arrangements.

Match the detector's scope, circuit type and response arrangement; arc detection does not necessarily provide interruption, and AC and PV DC devices are not interchangeable.

• IEC↗

Armour clamp

Cable-armour clamping element

The gland feature that mechanically captures armour wires or tape and can contribute to electrical continuity when designed for it.

Shown in armoured-gland exploded views, installation instructions and component schedules.

Match the clamp or cone to armour type and diameter, then verify retention, continuity and installation preparation separately.

• BSI↗
• IEC↗

Armour cone

Conical armour-termination component

A shaped component over which armour wires are arranged before being trapped by the mating clamping part of an armour gland.

Used in SWA and AWA gland assemblies, especially cone-and-ring or reversible-cone designs.

Confirm cone orientation, armour diameter range and wire preparation; incorrect lay or overlap can weaken retention and bonding.

• BSI↗

Armoured cable

Cable with metallic armour

A cable construction containing metallic wire or tape armour for mechanical protection and, where designed, electrical continuity.

Declared in cable schedules, project specifications and cable-gland selection worksheets.

Identify SWA, AWA, STA or another armour system and record armour diameter, sheath diameters and earthing requirements.

• BSI↗
• IEC↗

Assembly stack length

Combined axial length of an assembled set of parts

The axial dimension obtained by combining the relevant part thicknesses, gaps and overlaps from a common reference. Only dimensions that lie along that assembly path belong in the stack.

Used for panel, washer, seal, locknut and adaptor arrangements at cable entries.

Use installed seal thickness and account for overlaps before estimating available thread. A nominal length sum is different from evaluating the effects of dimensional tolerances.

• ISO↗
• ISO↗
• IEC↗

Associated apparatus

Apparatus associated with an intrinsically safe circuit

Apparatus containing circuits that affect intrinsic safety, with energy-limiting or related functions evaluated for connection to intrinsically safe circuits.

Used in intrinsic-safety barriers, isolators and system connection documents.

Check entity or system parameters, installation location and marking; associated-apparatus approval does not independently qualify every connected field device or cable.

• IEC↗
• IEC↗

ATEX

Atmosphères Explosibles

The European Union product-law framework for equipment and protective systems intended for use in potentially explosive atmospheres.

Appears in EU declarations, Ex certificates, equipment marking and hazardous-area purchasing specifications.

Determine the equipment group, category, protection concept and conformity route; ATEX is not a generic synonym for explosion proof.

• European Union↗

ATEX equipment category

ATEX equipment category

An ATEX classification indicating the required protection level within an equipment group, including M1/M2 for Group I and categories 1/2/3 for Group II with gas or dust designations where relevant.

Shown in ATEX equipment marking and EU conformity documents.

Match category to the assessed location and use, and check protection concept and certificate conditions; category alone is not a complete suitability decision.

• European Union↗

Autoclave / ETO sterilization

Moist-heat autoclave and ethylene-oxide sterilization

Autoclave sterilization uses a validated moist-heat process; ETO or EO sterilization uses ethylene oxide gas under controlled conditions. These are different processes with different material effects.

Used in medical-device manufacturing and reprocessing requirements for suitable components.

Validate the actual process and final assembly, including repeated cycles or residual-gas controls where relevant; neither method is implied by a cable-entry IP rating.

• ISO↗
• ISO↗

AWA

Aluminium wire armour

A cable armour construction using aluminium wires, commonly selected for single-core power cables to avoid magnetic heating effects.

Found in cable schedules, power-cable datasheets and armour-gland selection tables.

Select a gland whose armour clamping range and material arrangement match the actual AWA diameter and construction.

• BSI↗

AWG

American wire gauge

An established size designation for electrical conductors in which a higher gauge number generally corresponds to a smaller conductor size.

Found in North American cable markings, contact specifications and wire-selection tables.

Use a verified AWG-to-area reference and the actual conductor construction. AWG does not specify insulation thickness, complete cable diameter or ampacity by itself.

• UL Solutions↗
• IEC↗

Backshell

Connector rear termination housing

A housing fitted at the cable side of a connector to support protection, strain relief, screening or cable routing as specified by its construction.

Used on circular and specialist connectors and cable-assembly drawings.

Check cable range, attachment, screen termination and environmental sealing; a backshell can provide some of these functions without providing all of them.

• IEC↗
• IEC↗

Barrier gland

Compound barrier cable gland

A cable gland that incorporates a setting sealing compound around individual conductors to form a defined explosion-protection barrier.

Specified for particular flameproof equipment, cable constructions and hazardous-area installation conditions.

Check the applicable installation standard and certificate schedule; compound preparation, conductor separation and curing are critical.

• IEC↗
• IEC↗

Basic thread profile

Reference thread form before tolerances are applied

The theoretical profile used to define the basic geometry of a thread family. It provides reference dimensions; the actual manufactured crest, root and size are governed by the applicable profile and tolerance rules.

Used when interpreting metric-thread geometry and relationships between pitch and basic diameters.

The 60° metric-profile calculation does not establish a manufactured thread limit or gauge result. Confirm thread family, tolerance class and the drawing requirements.

• ISO↗
• ISO↗

Bayonet coupling

Connector coupling using pins and locking slots

A coupling mechanism that secures mating parts through engagement of pins or lugs with shaped slots, usually using a limited rotational movement.

Used on some circular connectors and the BNC connector interface.

Check the exact mating interface and positive locking indication; bayonet coupling describes a mechanism, not one universal connector standard or ingress rating.

• IEC↗
• IEC↗

Bend factor

Bend radius expressed as a multiple of cable diameter

The dimensionless ratio of a specified bend radius to the cable outside diameter, often written R/D. A stated factor is meaningful only with its radius convention and service condition.

Used to interpret cable bending instructions and estimate entry turning space.

Check whether the radius is measured to the inside surface or centreline, and distinguish installation, fixed and repeated-flexing duty. There is no universal factor for all cables.

• IEC↗
• Southwire↗

Bend protection

Cable-entry bend-protection feature

A tail, sleeve or support that distributes bending near an entry to reduce sharp local curvature and strain.

Specified on gland tails, connector boots and flexible-equipment cable entries.

Match support length and stiffness to the cable's minimum bend radius and movement duty; bend protection does not replace cable anchorage.

• IEC↗

Bend radius

Actual cable-path radius and minimum permitted bend radius

Bend radius describes the radius of a curved cable path. The minimum permitted bend radius is a separate manufacturer-specified limit for stated installation or service conditions; it is not necessarily the radius used in a layout or pulling calculation.

Checked in cable layouts, curved pulling paths and cable datasheets near glands, connectors, boxes and strain-relief points.

Use the actual path radius for arc length or sidewall-load calculations, then compare the installation with the cable manufacturer’s applicable minimum. Allow the required straight length after the entry and enclosure clearance; a gland does not cancel the bend limit.

• IEC↗
• IEC↗

Bifacial module

Photovoltaic module collecting light from both faces

A PV module designed to convert incident radiation reaching both its front and rear faces, with output affected by the surrounding installation.

Used in PV array energy and maximum-current assessments.

Account for relevant rear-side irradiance in electrical design and check mounting and cable routing; a front-side nameplate condition may not cover all operating current.

• IEC↗
• IEC↗

Biocompatibility

Biological compatibility for an intended medical use

The ability of a material or device to perform in a defined biological-contact application with an acceptable biological response, evaluated within a risk-management process.

Used in medical-equipment material and component evaluations where relevant body contact or exposure exists.

Define contact type, duration and final processed assembly. A material name or isolated test result does not establish general medical-device biocompatibility.

• ISO↗

Blanking plug

Unused-entry closure plug

A component fitted to an unused enclosure entry to maintain the intended closure, environmental protection and mechanical integrity.

Used on spare threaded holes in junction boxes, control panels and electrical equipment.

Match thread, sealing method, material and required rating; hazardous-area entries require a plug covered by the applicable approval.

• IEC↗
• IEC↗

BNC / coaxial connector

BNC and other coaxial connectors

A coaxial connector maintains concentric signal and return geometry; BNC identifies a particular bayonet-coupled coaxial interface within the broader connector family.

Used on radio-frequency, test and instrument cable assemblies.

Match the exact interface, impedance and cable termination; a BNC description does not make every coaxial connector interchangeable.

• IEC↗
• IEC↗

Bonding

Protective or functional electrical bonding

The intentional electrical connection of conductive parts to maintain a defined potential relationship or continuity path.

Referenced in armour terminations, EMC installations, earth-tag assemblies and equipment grounding details.

Confirm the required bonding function and tested current path; mechanical contact or a metallic finish alone may not be sufficient.

• IEC↗
• IEC↗

Braid

Braided cable screen or armour

An interwoven metallic layer used as an electrical screen, a flexible mechanical layer, or both depending on cable construction.

Shown in screened-cable cross-sections and EMC or special gland preparation instructions.

Record braid material and diameter and distinguish screen termination from armour retention before selecting the gland arrangement.

• IEC↗
• IEC↗

Braid carrier

Moving material-feed unit of a braiding machine

A braiding-machine unit that carries a bobbin and feeds its wire or yarn along a prescribed path. One carrier can feed several parallel wires; carrier count and wires per carrier are separate quantities.

Used to describe cable-screen braid construction and the inputs to geometric braid-coverage estimates.

Confirm carrier count, wires per carrier, wire diameter and braid geometry. Carrier count is not cable core count, and the count alone cannot establish screening performance.

• Herzog↗
• IEC↗

Braid optical coverage

Projected surface fraction covered by braid wires

The fraction of the surface beneath a braid that is obscured by its wires in the stated geometric projection. A braid model estimates this from wire dimensions and crossing geometry.

Used in preliminary cable-screen construction comparisons and braid-coverage estimates.

State the braid layer and measurement or model convention. Optical coverage is not shielding effectiveness or transfer impedance; frequency, material and terminations also affect EMC behaviour.

• IEC↗
• IEC↗
• New England Wire Technologies↗

Braid pick density

Braid crossings counted per unit axial length

The number of braid crossings over a stated length along the cable axis, commonly expressed as picks per inch or picks per millimetre. The counting convention belongs to the braid specification or model.

Used together with wire size and carrier information in braid geometry and coverage calculations.

Do not confuse crossing density with axial distance between crossings or the total carrier count. Convert length units and confirm the same counting convention before comparing values.

• IEC↗
• New England Wire Technologies↗

Branch / Y connector

Photovoltaic branch or Y connector

A connector arrangement joining multiple circuit branches into a specified electrical connection, often in a Y-shaped assembly.

Used when connecting parallel PV branches or adapting defined cable arrangements.

Check total current, polarity, protection, connector identity and the rated mating combinations; the shape does not establish the electrical circuit or current capacity.

• IEC↗
• IEC↗

Brass

Copper-zinc alloy family

Brass is a family of copper-zinc alloys whose composition, additives and manufacturing condition affect machinability, strength and corrosion behaviour.

Used for gland bodies, locknuts, adaptors and connector components.

Require the specific alloy and finish and check environmental compatibility; plain brass, plated brass and dezincification-resistant grades have different selection implications.

• ISO↗
• ISO↗

Breakdown voltage

Voltage at which electrical breakdown occurs in a stated test

The voltage associated with an observed electrical breakdown of a specified insulation arrangement. The result depends on specimen, electrode geometry, waveform, application time and surrounding conditions.

Used in insulation-material tests and interpretation of electric-field calculations.

Distinguish measured breakdown voltage from a voltage merely applied during a withstand test. Neither value is automatically the rated voltage of a finished connector or cable entry.

• IEC↗
• IEC↗

BSPP / G

British Standard Pipe Parallel thread

A parallel pipe-thread family with a 55° included profile angle, designated G under ISO 228. Pressure-tight sealing is not made on the thread flanks; a complete fitting needs its specified sealing arrangement.

Found on glands, adaptors, conduit fittings and equipment entries supplied for international projects.

Confirm size, tolerance, gasket or other sealing interface. A fractional pipe-size label is not the measured outside diameter, and similar-looking NPT or BSPT threads are not substitutes.

• ISO↗

BSPT / R

British Standard Pipe Taper thread

A tapered external pipe thread designated R within the ISO 7 family for joints intended to seal on the thread form.

Found on conduit fittings, adaptors and some regional enclosure entries.

Confirm the female form, engagement and approved sealing practice; BSPT and NPT have different geometry and are not interchangeable.

• ISO↗

Bubble point

First-bubble pressure of a wetted porous specimen

The pressure at which gas first forms bubbles through a liquid-wetted porous specimen in a defined test, relating to an accessible flow path and the wetting liquid.

Used in membrane integrity and porous-material characterization.

Specify wetting liquid, temperature and method. Converting bubble pressure to pore size requires model assumptions and does not directly establish an installed vent's IP rating.

• ISO↗
• ISO↗

Burr / swarf

Unwanted edge projections and machining debris

A burr is an unwanted raised edge left by cutting or forming; swarf is loose material produced by machining. Either can damage seals or insulation.

Checked after drilling, tapping or modifying enclosure entries.

Deburr and remove debris using a method that preserves the specified edge and surface; inspect hidden entry faces before fitting the gland or connector.

• IEC↗
• IEC↗

Butyl rubber

Isobutylene-isoprene rubber

Butyl rubber, commonly abbreviated IIR, is an elastomer based mainly on isobutylene with a smaller isoprene component; halogenated butyl variants are separate material designations.

Used in selected sealing, gas-barrier and protective material applications.

Check the exact compound and fluid, temperature and compression requirements; low gas transmission does not by itself prove an assembled seal is hermetic.

• ISO↗
• ISO↗

BW / CW gland

BW and CW armoured cable-gland construction labels

BW commonly denotes an armour-terminating gland without an outer-sheath environmental seal; CW commonly includes that seal. These are construction labels, not complete performance ratings.

Used in British-pattern SWA gland schedules and indoor or outdoor installation descriptions.

Check the actual armour clamp, sheath seal, cable ranges and declared ingress rating. An outdoor label does not establish submersion or Ex suitability.

• BSI↗
• IEC↗

Bypass diode

Diode providing a bypass path in a PV module

A diode connected across a defined group of PV cells to allow current to bypass that group under specified conditions such as shading or cell mismatch.

Used in PV module junction boxes and module circuit diagrams.

Review the module's arrangement and thermal limits; a bypass diode serves a different function from a blocking diode and does not replace string overcurrent protection.

• IEC↗
• IEC↗

C-type / E1 gland

C-type and E1 armoured cable-gland construction labels

Legacy armoured-gland labels commonly associated with outer-sheath sealing for C-type and both inner- and outer-sheath sealing for E1 constructions.

Encountered in armoured-gland replacement lists and British-pattern construction drawings.

Confirm the manufacturer's section drawing, armour range and individual seal ranges. Variants such as E1X need their own specifications and certificates.

• BSI↗
• IEC↗

Cable bundle envelope

Outer boundary enclosing a group of cables

The enclosing outline of a cable group, including the gaps between its individual cables. An estimated equivalent circular envelope is a model of the group, not the outside diameter of any one cable.

Used to estimate routing space, bundle openings and packing area for cable groups.

Check actual cable diameters, arrangement and deformation. An area estimate does not prove that the bundle is circular, fits a specific seal or provides a sealed path between individual cables.

• ISO↗
• IEC↗

Cable carrier

Guided support for moving cables

An articulated or otherwise guided structure that carries cables through a controlled movement path while limiting their bend geometry.

Used on automated machinery, moving axes and industrial handling equipment.

Match carrier bend radius, fill and separation to each cable, and anchor the stationary ends so carrier motion is not transferred into entry seals.

• IEC↗
• IEC↗

Cable cleat

Cable-securing cleat

A device that secures cables to a support and, when specified and tested, restrains movement caused by short-circuit forces.

Used along power-cable runs and near terminations where mechanical loads must be supported.

Select for cable formation, size, mounting and declared short-circuit duty. A gland's retention rating does not replace the required cable-cleat system.

• IEC↗

Cable cold flow

Time-dependent cable-jacket deformation

Slow deformation of a cable's polymeric jacket or insulation under sustained load, which can change contact pressure and dimensions without melting.

Relevant where glands or clamps continuously compress soft cable jackets.

Check jacket material, temperature, clamping pressure and long-term retention; increasing tightening torque can worsen deformation instead of correcting it.

• ISO↗
• IEC↗

Cable entry device

Device for introducing a cable into equipment

A general term for a component that allows a cable to pass into an enclosure while providing one or more retention or sealing functions.

Used in product standards, equipment specifications and selection discussions that cover more than conventional glands.

Clarify whether sealing, retention, armour clamping, EMC contact, strain relief or hazardous-area protection is required.

• IEC↗
• IEC↗

Cable gland

Mechanical cable-entry device

A device designed to permit cable entry into electrical equipment and provide retention, sealing or other declared functions.

Used at enclosure, machine, junction-box and connector interfaces in industrial and electrical installations.

Select from the cable construction, outside diameter, entry interface and environment; the product name alone does not define suitability.

• IEC↗

Cable harness

Organized cable and wire assembly

An assembly of cables or wires routed and secured together, often with connectors, branches, protective sleeves and identified terminations.

Used in machinery, control panels and equipment supplied with preassembled wiring.

Specify branch geometry, connector envelopes and termination sequence so the entry system can accept the harness without damaging preterminated parts.

• IEC↗
• IEC↗

Cable migration

Cable movement through a retained entry

Progressive or sudden axial displacement of a cable relative to a gland or clamp under mechanical load, temperature changes or vibration.

Investigated after pull tests, repeated movement or loosening of a cable-entry seal.

Verify anchorage on the actual jacket material, cable support and installation torque; a seal can appear tight while the cable still moves under service load.

• IEC↗

Cable occupied cross-sectional area

Area enclosed by the outer cable profile

The cross-sectional area occupied by the complete cable, including its sheath and internal spaces. A circular outer profile of diameter D occupies πD²/4.

Used in cable-bundle, entry-layout and transit-area estimates.

Use the actual outside profile and its tolerances. This area is not the conducting metal area, the envelope of a bundle or evidence that a certified transit layout is satisfied.

• ISO↗
• IEC↗

Cable outside diameter

Overall cable outer-sheath diameter

The measured maximum outside dimension of the cable at the location where the gland seal will contact the outer sheath.

Recorded on cable datasheets, inspection sheets, gland schedules and quotation forms.

Compare actual production tolerance and shape with the gland sealing range; nominal conductor area does not determine gland size.

• IEC↗

Cable penetrator

Sealed cable penetration assembly

An assembly that carries a cable or conductors through a pressure or environmental boundary, using a defined sealing or bonded interface.

Used at bulkheads, subsea equipment and pressure-containing instrument housings.

Verify pressure direction, leakage limit, cable construction and termination method. A cable penetrator is not automatically interchangeable with an enclosure gland.

• IEC↗
• ISO↗

Cable pulling tension

Tensile force transmitted during cable installation

The force acting along a cable while it is pulled through a route. Cable mass, elevation, friction, bends and the pulling arrangement affect the tension at different positions.

Used in cable installation planning and checking pull equipment and attachments.

Use the cable and pulling-device limits for the actual construction and method. Check bend sidewall loading separately; a gland retention-test result is not a pulling-tension allowance.

• ISO↗
• Southwire↗

Cable screen

Conductive electromagnetic screen

A conductive layer intended to reduce electromagnetic coupling into or out of the cable and to provide a controlled termination path.

Declared in instrumentation, control, data and variable-frequency-drive cable constructions.

Identify foil, braid or combined construction and specify how continuity and termination are to be maintained through the entry.

• IEC↗
• IEC↗

Cable sidewall bearing pressure

Cable bend loading expressed as force per unit length

A cable-installation measure of lateral loading while tensioned cable passes around a bend. For the simple single-cable model it is T/R, expressed in N/m or an equivalent force-per-length unit.

Used with pulling tension and bend radius to assess installation routes.

Use the applicable cable arrangement and manufacturer limit. This line-load quantity is not a contact stress in pascals; multiple-cable layouts can require different relationships.

• ISO↗
• Southwire↗

Cable stiffness

Resistance of a cable to bending

The mechanical resistance of a complete cable to curvature, influenced by its materials, diameter, conductor arrangement, armour and temperature.

Considered in entry alignment, handling, vibration and cable-support layout.

Allow suitable bend radius and support so a stiff cable does not impose excessive side load on the gland, connector or enclosure wall.

• IEC↗
• IEC↗

Calibration

Establishing a relation between indications and reference values

An operation that establishes the relationship between instrument indications and reference quantity values under specified conditions, including associated uncertainties.

Used for gauges, torque tools, electrical meters and leak-test equipment.

Check calibration range and uncertainty for the intended measurement; calibration differs from adjustment and does not itself certify that a product meets its specification.

• ISO / IEC↗

Capillary action

Liquid motion driven by narrow-gap surface forces

Movement or retention of liquid in narrow spaces caused by surface tension and wetting, including gaps between strands or within porous materials.

Considered in cable water migration, fine sealing gaps and porous vent membranes.

Assess cable construction and wettability as well as the outer entry seal; closing the jacket interface may not stop a liquid path inside the cable.

• ISO↗
• ISO↗

Carbon black

Carbon-black particulate additive

A carbon-rich particulate material used as an additive for functions such as pigmentation, UV protection or electrical-property modification, depending on its type and loading.

Found in black cable jackets, polymers and static-control material specifications.

Check the formulation and measured properties; black colour alone does not establish UV durability or static-dissipative behaviour.

• ISO↗

CE marking

European conformity marking

A marking used for products placed on the European Economic Area market when applicable EU legislation requires conformity assessment.

Appears on products, labels, declarations and market-access documentation for in-scope equipment.

Identify the legislation that applies to the complete product; CE is not itself a cable-gland performance standard or test report.

• European Union↗

Centre distance

Distance between the centres of specified features

The straight-line distance between the centres of two identified features. For circular features on a common plane, subtracting their radii gives the edge-to-edge gap along the line of centres.

Used to space cable entries, connector openings and holes in gland plates or multi-hole seals.

Specify the feature centres and measurement plane. In a circular pattern, centre distance is a chord; it differs from arc length and angular spacing.

• ISO↗

Certificate

Third-party conformity certificate

A document issued under a defined certification scheme that identifies the product, standards, scope and conditions covered.

Requested in supplier qualification, hazardous-area projects and regulated-market documentation packs.

Match the exact model, variants, issuing body, edition and schedule; a family brochure or test summary is not a substitute.

• IECEx↗
• OSHA↗

CFD

Computational fluid dynamics

A numerical modelling approach for fluid flow and associated transport phenomena based on governing equations, discretization and specified boundary conditions.

Used in enclosure airflow, membrane flow and heat-transfer studies.

Verify the model, mesh, boundary conditions and validation evidence; a simulated flow result does not independently establish a vent or enclosure performance rating.

• ASME↗
• ISO↗

Chamfer

Bevelled edge at an interface

A sloping transition made at a hole, part edge or thread entrance to remove a sharp edge or assist assembly.

Specified on gland-entry holes, sealing interfaces and machined fitting drawings.

Confirm chamfer size and location; excessive edge removal can reduce seal support or effective thread engagement even if assembly becomes easier.

• ISO↗
• IEC↗

Chemical resistance

Resistance to specified chemical exposure

The ability of a material or assembly to retain required properties during exposure to named chemicals at stated conditions.

Used in material tables for glands, seals, junction boxes and conduit systems.

Name the chemical, concentration, temperature, duration and stress; a broad compatibility label cannot cover every exposure.

• IEC↗

Circular connector

Multi-contact connector with a circular interface

A separable electrical connector whose mating interface and shell are circular, often using threaded, bayonet or push-pull coupling.

Used on machinery, sensors, control equipment, marine equipment and industrial cable assemblies.

Confirm contact count, keying, ratings, termination, coupling, environment and mating compatibility; shell diameter alone is insufficient.

• IEC↗

Circular mil

Area of a circle one thousandth of an inch in diameter

A circular mil is the area of a circle with a diameter of one mil, where one mil is 0.001 inch. A round section with diameter d in mils has an area of d² circular mils.

Used in inch-based conductor-size descriptions and conversion to square millimetres.

Distinguish circular mil from square mil and kcmil from cmil. The conversion describes area and does not establish an equivalent cable construction, resistance limit or ampacity.

• ISO↗
• NIST↗
• UL Solutions↗

Clamping insert

Internal cable clamping or sealing insert

A shaped internal element that compresses around the cable or transfers tightening force within a gland or cord grip.

Shown in gland exploded drawings and replacement-part or installation instructions.

Use the insert supplied for the exact body and cable range; mixing inserts can change retention, compression and sealing behaviour.

• IEC↗

Class / Division classification

North American hazardous-location Class and Division system

A classification system in which Class identifies gas/vapour, dust or fibres/flyings hazards and Division distinguishes conditions of hazardous-atmosphere presence under the applicable rules.

Used on North American equipment approvals and hazardous-location wiring drawings.

Check the exact Class, Division, group and temperature requirements; do not convert directly to an IEC Zone or assume an ATEX certificate covers the location.

• OSHA↗
• IEC↗

Clearance

Shortest distance through air

The shortest distance in air between two conductive parts, used when evaluating insulation coordination and electrical safety.

Specified in connector inserts, terminal boxes, PCB assemblies and high-voltage interface drawings.

Select for rated impulse voltage, pollution degree and overvoltage category; it is different from creepage distance along a surface.

• IEC↗
• IEC↗

CMM

Coordinate measuring machine

A measuring system that determines coordinates of points on a workpiece to evaluate dimensions and geometric features using a stated probing and evaluation method.

Used in inspection of machined gland parts, connector interfaces and enclosure features.

Check machine verification, probe, fixturing and measurement uncertainty; CMM availability alone does not establish the accuracy of a particular inspection result.

• ISO↗

Coating adhesion

Attachment of a coating to its substrate

The ability of a deposited layer to remain attached at the substrate interface under a specified assessment. Adhesion, coating thickness, porosity and corrosion resistance describe different characteristics.

Used in nickel-finish specifications, surface-preparation checks and coating-quality inspection.

Specify substrate preparation, coating process and the appropriate adhesion test. A qualitative test result does not provide a universal bond-strength value or guarantee protection in the intended environment.

• ISO↗
• ISO↗

Coating porosity / holidays

Coating pores and discontinuities

Porosity describes pores within or through a coating; a holiday is a discontinuity that exposes the substrate in a protective coating. Their significance depends on the coating system.

Checked in metal finishes and protective coatings on entry components or enclosures.

Specify the coating type and detection method; a sound appearance or nominal thickness does not prove the absence of through-defects.

• ISO↗
• ISO↗

Coaxial cable

Coaxial transmission cable

A cable with a central conductor, surrounding dielectric and a concentric outer conductor or screen, usually with an outer protective jacket.

Used for radio-frequency signals, instrumentation and some communication links.

Match connector impedance and dimensions, preserve the dielectric and screen geometry, and observe cable bending and termination limits.

• IEC↗

Coefficient of friction

Ratio of friction force to normal force

A parameter describing resistance to sliding for a defined pair of surfaces and condition; it can vary with lubricant, finish, pressure and temperature.

Used when relating tightening torque to clamping load and evaluating seal or cable sliding.

Use values for the actual surface condition. Adding lubricant or anti-seize can change the joint load even when the specified torque is unchanged.

• ISO↗

Collet

Segmented gripping collet

A slotted or segmented clamping element that closes around a cable or another cylindrical part when compressed by a mating component.

Appears in gland retention assemblies, strain-relief fittings and connector backshells.

Check the gripping diameter, cable-jacket compatibility and required tightening method; a collet may retain the cable without providing the environmental seal.

• IEC↗

Combiner box

Enclosure combining photovoltaic circuit branches

A box or assembly that brings multiple PV source circuits together and may contain terminals, protection, switching or monitoring according to its design.

Used between PV strings and downstream DC equipment.

Check complete assembly voltage, current, protection, thermal and ingress duties; the empty enclosure rating does not establish the finished combiner's suitability.

• IEC↗
• IEC↗

Common-mode / differential-mode

Common-mode and differential-mode electrical quantities

Common-mode components occur in the same sense on conductors relative to a reference; differential-mode components are defined between conductors and have opposing contributions in a balanced description.

Used when analyzing conducted interference, cable shielding and filtering.

Identify the relevant conductors, reference and return paths. A treatment effective for one mode may not suppress the other.

• IEC↗
• IEC↗

Comparative tracking index (CTI)

Comparative tracking index

CTI is a test-derived index characterizing resistance of solid insulating material to formation of conductive surface tracks under specified wet-contaminant and voltage conditions.

Used in insulation material comparisons and creepage-distance assessment.

Require the test method and actual grade or colour; CTI is distinct from dielectric strength, flame class and a finished product's voltage rating.

• IEC↗
• IEC↗

Compression nut

Cable-gland sealing nut

The gland part tightened to compress an elastomeric seal or clamping insert around the cable outer sheath.

Visible on most nylon, brass and stainless-steel compression-gland assemblies.

Follow the stated torque or assembly position; excessive tightening can damage the sheath or seal while too little reduces retention.

• IEC↗

Compression set

Permanent deformation after seal compression

The residual deformation remaining after an elastomer has been compressed for a specified time and temperature and then allowed a defined recovery period.

Reported in rubber datasheets and long-term seal-material comparisons.

Compare only results with equivalent test conditions; compression set does not directly measure the sealing force remaining while the seal is still compressed.

• ISO↗

Concentricity / eccentricity

Common-centre alignment and centre offset

Concentricity concerns the alignment of centres or axes of features under a stated geometric specification; eccentricity describes an offset between them.

Used in entry-hole machining, seal alignment and rotating or cylindrical interface checks.

Specify the actual datum and geometric tolerance. Offset can produce uneven seal compression even when each individual diameter is within limits.

• ISO↗

Condensation

Conversion of vapour into liquid

Formation of liquid when water vapour reaches conditions at which it can condense, including on an enclosure surface colder than the local dew point.

Investigated in outdoor junction boxes and equipment exposed to temperature changes.

Assess internal moisture and surface temperatures and control water paths; a sealed or IP-rated enclosure can still develop internal condensation.

• ISO↗
• IEC↗

Conductive dust

Dust classified as electrically conductive

A dust having electrical resistivity below the threshold specified by the governing classification standard, rather than merely having a metallic appearance.

Used in explosive-dust group assessment and equipment selection.

Use the actual dust characterization and applicable threshold; conductive-dust duty requires the relevant Ex marking and ingress arrangements.

• IEC↗
• IEC↗

Conductor

Electrically conductive cable element

A cable element intended to carry electric current, normally copper or aluminium and used as a solid or stranded construction.

Listed in cable schedules, connector termination data and barrier-gland preparation instructions.

Confirm conductor count, size, stranding and insulation; hazardous-area barrier seals may require preparation around each insulated core.

• IEC↗
• IEC↗

Conductor class

Standardized conductor construction class

An IEC conductor category distinguishing solid, stranded and flexible constructions, with requirements including wire dimensions and electrical resistance.

Used in cable specifications and connector compatibility checks, including IEC classes 1, 2, 5 and 6.

Match the contact and tooling to the declared conductor class. A flexible conductor class alone does not establish continuous-flex cable service life.

• IEC↗

Conductor cross-sectional area

Nominal conductor size and conducting metal area

Conductor cross-sectional area describes the area of conducting metal. A nominal conductor size in square millimetres is a standardized designation and need not equal the measured geometric sum of the individual wire areas; neither is the outside area of an insulated cable.

Used in cable schedules, resistance and current-density calculations, and connector wire-size specifications.

Use the conducting area appropriate to the calculation and distinguish it from the nominal size used for specification and resistance limits. Select gland seals using actual cable OD and contacts using the permitted conductor size and construction; do not substitute the insulated cable area for metal area.

• IEC↗

Conductor stranding

Arrangement of individual conductor strands

The number, diameter and arrangement of wires forming a stranded conductor, including construction choices that affect flexibility and termination behaviour.

Shown in cable datasheets and contact or crimp-tool specifications.

Confirm strand construction as well as nominal area; fine-stranded wire may require different contacts, ferrules and crimp settings from a solid conductor.

• IEC↗

Conduit fitting

Connector or coupling for a conduit system

A component used to join conduit sections or connect conduit to an enclosure while providing declared mechanical or environmental functions.

Found on flexible and rigid conduit systems, boxes, machines and cable-management installations.

Match the conduit type, nominal size, entry thread, pull-out duty and ingress requirement; it is not automatically a cable gland.

• IEC↗
• IEC↗

Conduit hub

Conduit-to-enclosure connection fitting

A fitting that connects a conduit system to an enclosure entry, with defined mounting, retention and any sealing or bonding functions.

Used on junction boxes, control panels and conduit entry assemblies.

Check the conduit and entry thread, enclosure thickness and required environmental rating; an ordinary cable gland is not a conduit hub.

• IEC↗
• IEC↗

Constant-volume gas temperature–pressure relation

Absolute pressure ratio at fixed gas amount and volume

For an ideal gas with unchanged amount and volume, absolute pressure divided by absolute temperature remains constant. The relation therefore uses absolute pressure and kelvin temperature at both states.

Used for preliminary pressure-change estimates in a closed, rigid enclosure during a gas-temperature change.

Leakage, vent flow, condensation and enclosure deformation can invalidate the assumptions. Convert gauge pressure to absolute pressure using the applicable ambient pressure before applying the relation.

• ISO↗
• ISO↗

Contact angle / wettability

Contact angle and tendency of a liquid to spread

Contact angle characterizes a liquid's shape where it meets a solid under defined conditions; wettability describes how readily that liquid spreads or maintains contact on the surface.

Used in membrane repellency, coating evaluation and capillary-entry analysis.

Specify liquid, surface condition and measurement method; a water contact angle does not establish resistance to oil, detergents or contaminated water.

• ISO↗

Contact resistance

Electrical resistance of a mated contact pair

The resistance attributable to the current path through mating connector contacts under stated measurement and conditioning requirements.

Published in circular, waterproof and photovoltaic connector specifications and test records.

Compare the defined measurement method, current and conditioning; rising resistance can indicate contamination, damage or poor termination.

• IEC↗
• IEC↗

Continuous-flex cable

Cable designed for repeated flexing

A cable construction intended for repeated bending under a specified motion, bend radius, speed and environmental duty.

Used in cable carriers, moving machinery and robotic wiring.

Require the cable's actual motion specification and support the fixed entry separately; conductor flexibility alone does not establish a flex-cycle rating.

• IEC↗
• IEC↗

Cord grip

Flexible-cord strain-relief fitting

A fitting primarily intended to grip and relieve strain on a flexible cord, with sealing functions depending on its declared design.

Common North American catalog language for machine, appliance and enclosure cable-entry fittings.

Check listing category, cord type, diameter and enclosure function; do not assume every cord grip has the same duties as IEC 62444 glands.

• IEC↗
• OSHA↗

Core

Individually insulated conductor assembly

A conductor together with its insulation, forming one functional insulated element within a multi-core or single-core cable.

Used in cable descriptions, connector pin assignments and barrier-gland installation steps.

Record core count, insulation diameter and layout where the entry or sealing compound interacts with individual cores.

• IEC↗
• IEC↗

Corona resistance / arc resistance

Resistance to damage from distinct electrical discharges

Corona resistance concerns deterioration caused by localized gas-ionization discharges around stressed insulation. Arc resistance concerns damage from an arc discharge; high-voltage, low-current arc testing has a specific screening scope.

Used in insulation and silicone material descriptions for electrically stressed components.

Specify discharge conditions, geometry, test method and acceptance criteria. Corona, arc resistance, dielectric strength and tracking resistance are different properties and do not establish a connector voltage rating by themselves.

• IEC↗
• IEC↗
• IEC↗

Coulometric measurement

Measurement using electric charge in a defined reaction

A technique deriving a quantity from measured electric charge; coating-thickness coulometry commonly removes a coating by controlled anodic dissolution and relates charge to thickness.

Used in metal-plating inspection and other specified electrochemical measurements.

Identify the coating system, exposed area and end-point method and control calibration; coulometric and X-ray thickness methods have different assumptions and limitations.

• ISO↗

Counterbore / countersink

Cylindrical and conical hole recesses

A counterbore is a cylindrical enlargement of a hole; a countersink is a conical enlargement. They accommodate different head or seating geometries.

Shown on panel and mounting drawings for entry accessories and fasteners.

Specify the required form, diameter and depth. Neither recess should remove the continuous sealing land or reduce necessary wall engagement.

• ISO↗
• IEC↗

Coupling nut

Connector mating and locking nut

A rotatable connector component that draws mating halves together and maintains the specified engagement or locking condition.

Used on threaded circular connectors, waterproof connectors and some photovoltaic connector designs.

Use only with the matching connector series and observe engagement indication or torque; it is not a cable-gland compression nut.

• IEC↗
• IEC↗

CR

Chloroprene rubber

CR is the standardized rubber abbreviation for chloroprene-based elastomer, used in various formulated sealing and protective compounds.

Appears in seal, gasket and flexible-boot material descriptions.

Check compound-specific fluid, ozone, temperature and compression data; a common trade description does not identify one uniform seal formulation.

• ISO↗
• ISO↗

Creep

Time-dependent deformation under sustained stress

Progressive deformation while a material remains under an applied load, with the response depending on temperature, material and time.

Relevant to plastic gland threads, cable jackets, supports and compressed polymer interfaces.

Assess long-term loading and service temperature. Creep differs from stress relaxation, where the maintained condition is deformation rather than load.

• ISO↗
• ISO↗

Creepage distance

Shortest path along an insulating surface

The shortest distance along the surface of solid insulation between two conductive parts under the defined electrical conditions.

Used in connector, terminal and enclosure insulation-coordination specifications.

Evaluate with working voltage, pollution degree and material group; increasing air clearance does not necessarily increase creepage.

• IEC↗
• IEC↗

Crevice corrosion

Localized corrosion within a restricted gap

Corrosion concentrated in a narrow region where fluid exchange is restricted, such as beneath a seal, washer or deposit.

Relevant to metal gland shoulders, threaded joints and gasketed enclosure interfaces.

Control crevice geometry and exposure and select a suitable alloy; an intact-looking outer surface does not exclude attack beneath a seal.

• ISO↗

Crimp barrel / ferrule

Crimp barrel and wire-end ferrule

A crimp barrel is the deformable contact region that captures a conductor; a wire-end ferrule is a sleeve crimped over conductor strands for a compatible terminal. Similar sleeve terms can denote different parts.

Used in connector contacts, terminal blocks and crimp assembly instructions.

Match part, conductor class and tooling to the intended connection; a ferrule must not be substituted for a connector's specified crimp contact.

• IEC↗
• IEC↗

Crimp contact

Contact terminated by controlled crimping

A connector contact attached to a conductor by permanent mechanical deformation using a specified tool, die and preparation.

Used in circular, waterproof and photovoltaic connector cable assemblies.

Match wire range, contact, strip length and tooling; pull-out and contact-resistance results depend strongly on the crimp process.

• IEC↗
• IEC↗

Crimp die

Crimp-forming tool die

The shaped tooling surfaces that deform a specified contact or sleeve around a conductor to achieve the intended crimp geometry.

Specified in contact assembly instructions and cable-assembly production.

Use the approved die, locator and conductor combination and perform required checks; a tool accepting the wire size is not sufficient evidence of a suitable crimp.

• IEC↗

Cross-bonding

Cross-connected power-cable sheath bonding

A sheath-bonding arrangement that cross-connects sectionalized cable sheaths or screens between phases to reduce the net induced voltage over a designed section.

Used on suitable high-voltage single-core cable routes and link-box schemes.

Follow the engineered section and bonding design, including insulation and surge protection; it is not ordinary interchange of protective-earth connections.

• IEC↗
• IEC↗

Cross-linking

Formation of links between polymer chains

A chemical or physical process that connects polymer chains into a network, changing their response to heat, load and solvents.

Relevant to rubber curing, thermoset potting and cross-linked cable insulation.

Identify the material and process and verify cure quality; cross-linking is not a single performance grade or proof of fire resistance.

• ISO↗

Cross-threading

Incorrect engagement of mating thread turns

Damage or misassembly caused when a threaded part begins at an incorrect angle or engages the wrong thread path instead of the intended helix.

Encountered when installing glands, locknuts and adaptors in restricted access.

Start the correct matching thread squarely and inspect damaged parts. Increased torque must not be used to force an incorrectly started interface into place.

• ISO↗
• IEC↗

Crosstalk

Unwanted coupling between signal paths

A disturbance on one signal path caused by a signal on another path through electromagnetic coupling or a shared structure.

Measured in multi-pair cables, connectors and densely routed communication systems.

Check the applicable frequency and near- or far-end method, and preserve pair geometry during termination; cable spacing alone may not address every coupling path.

• IEC↗
• IEC↗

Crystallinity

Degree of ordered structure in a polymer

The extent to which polymer chains form ordered crystalline regions rather than amorphous regions, with the measured result depending on method and processing history.

Used in polymer-grade and thermal-analysis discussions for cable and entry components.

Consider moulding, cooling and conditioning history; crystallinity can affect dimensional response and properties but is not a finished-part performance rating.

• ISO↗
• ISO↗

Current density

Electric current per area normal to its flow

The electric current crossing a surface per unit area. For uniform current through a conductor, the average magnitude is J = I/A, with the conducting metal area A as the denominator.

Used in conductor-area and preliminary electrical-loading calculations.

Use compatible area units and account for non-uniform AC current distribution where relevant. An assumed current density does not by itself establish permitted cable ampacity or connector loading.

• IEC↗
• IEC↗

Current derating

Reduction of permitted current for operating conditions

Adjustment of a connector or component's allowable current according to conditions such as ambient temperature, conductor size, number of loaded contacts and heat dissipation.

Shown as current-temperature curves and installation constraints.

Use the curve for the exact assembly and test conditions; a maximum catalogue current is not automatically available at every temperature or wiring configuration.

• IEC↗

Current efficiency

Fraction of electric charge used by a specified electrode reaction

The fraction of the total current or passed charge that produces the selected electrochemical reaction. In metal deposition it adjusts the theoretical Faraday-law deposit for competing reactions.

Used when estimating average electroplated metal mass or coating thickness.

Use the efficiency for the actual bath, electrode and conditions. A value of 100% is an ideal assumption, and current efficiency is not the electrical energy efficiency of the plating equipment.

• ISO↗
• Nickel Institute↗

Damp heat

Environmental exposure combining heat and humidity

A test condition combining elevated temperature and high humidity under a specified steady or cyclic procedure to examine a specimen's response.

Used in connector, enclosure and insulating-material environmental qualification.

Require the exact test, duration and measured outcome; steady damp heat and cyclic condensation tests expose assemblies differently.

• IEC↗
• IEC↗

Datum / reference face

Defined reference for dimensions and measurements

A datum is a theoretically exact reference established from specified features under a geometrical specification. A reference face identifies the surface from which a particular dimension or measurement is taken.

Used to define panel-stack thickness, usable projection, hole positions and installation-interface measurements.

Identify the intended reference and tolerance scheme on the drawing. A named measurement face in a simple stack calculation does not by itself define a complete geometrical datum system.

• ISO↗

DC breaking capacity

Ability to interrupt a specified DC current

A rating or assessed capability of a switching or protective device to interrupt direct current under stated voltage, current and circuit conditions.

Used for PV disconnectors, circuit breakers and other DC switching equipment.

Require the relevant DC duty and circuit configuration; a PV connector without rated load-breaking capability must not be treated as a disconnector.

• IEC↗
• IEC↗

Declaration of conformity

Manufacturer’s formal conformity declaration

A signed document by which the responsible manufacturer or supplier declares conformity with identified legislation or standards.

Included in CE, ATEX and other regulated-market technical documentation when the applicable route calls for it.

Check responsible party, exact product, legislation and standard editions; it is different from an independent certification-body certificate.

• European Union↗

Delamination

Separation between layers or bonded interfaces

Loss of attachment between layers of a material or assembly, potentially caused by loading, ageing, manufacturing defects or incompatible exposure.

Investigated in coated parts, laminated materials, cable layers and encapsulated assemblies.

Check adhesion and service conditions for the specific interface; a layer remaining visually intact does not prove it is still bonded to its substrate.

• ISO↗
• ISO↗

Desiccant breather

Breather using a moisture-adsorbing medium

A breather that directs exchanged air through a desiccant to reduce its moisture content while permitting a defined pressure-balancing function.

Used on selected equipment housings and systems sensitive to moisture entry.

Check exchange flow, desiccant capacity, saturation indication and replacement procedure; the device cannot keep drying indefinitely without maintenance.

• IEC↗
• ISO↗

Device under test (DUT)

Device under test

The particular specimen, assembly or equipment subjected to a test under a defined configuration and procedure.

Identified in electrical, ingress, mechanical and EMC test reports.

Record model, condition, accessories and assembly configuration; a passing DUT result represents the stated specimen and scope rather than every related product.

• IEC↗
• IEC↗

Dew point

Temperature at which water vapour begins to condense

The temperature at which air with a stated water-vapour content reaches saturation under the specified pressure conditions.

Used in enclosure moisture assessment and environmental measurements.

Compare dew point with the coldest relevant internal surface and account for changing conditions; air temperature alone cannot determine condensation risk.

• ISO↗
• IEC↗

Dezincification

Selective removal of zinc from brass

A form of selective corrosion in which zinc is preferentially removed from a susceptible copper-zinc alloy, leaving a weakened copper-rich structure.

Investigated in brass fittings exposed to particular water chemistries and corrosive conditions.

Require the actual brass grade and relevant resistance evidence; colour, plating or a generic brass label does not establish dezincification resistance.

• ISO↗
• ISO↗

Diaphragm seal

Cable-entry diaphragm seal

A thin flexible membrane with a defined opening that deforms around a cable or is pierced during an approved installation procedure.

Used in enclosure entries, membrane grommets and some gland sealing inserts.

Check permitted cable diameters, piercing instructions and retention requirements. A diaphragm seal need not provide the same anchorage as a cable gland.

• IEC↗
• IEC↗

Dielectric absorption current

Time-dependent current associated with dielectric polarization

A time-dependent current component associated with polarization of insulation after a voltage is applied. It differs from steady conductive leakage and from the initial capacitive charging current.

Used when interpreting the changing current observed during DC insulation-resistance measurements.

Record test voltage and elapsed time. An early V/I value can include transient components and should not be reported as an established steady insulation resistance.

• IEC↗
• Keithley / Tektronix↗

Dielectric strength

Resistance to electrical breakdown under a defined test

A material or insulation system's ability to withstand an applied electric field or voltage without breakdown under specified conditions.

Used in dielectric tests of connector insulation, feed-throughs and insulating gland components.

Identify the geometry, waveform, duration and environment; material dielectric strength and an assembly's rated operating voltage are different properties.

• IEC↗
• IEC↗

Differential pressure

Difference between two pressures

The pressure at one specified location minus the pressure at another, with sign and reference points defined by the application.

Used across vent membranes, enclosure walls and pressure-loaded seals.

State both reference locations and operating range; the same gauge pressure can produce different differential loads when the surrounding pressure changes.

• ISO↗

Dimensional stability

Retention of dimensions under stated conditions

The ability of a part to retain its dimensions within specified limits during time, temperature, moisture, load or chemical exposure. It is broader than a single thermal-expansion or moulding-shrinkage value.

Used for polymer entry threads, locking features, seal housings and precision mating interfaces.

Define the measured dimensions, conditioning, exposure and allowable change. Reinforcement can affect different directions differently; verify the finished component rather than assuming zero deformation from the material name.

• ISO↗
• ISO↗
• ISO↗

Dimensional tolerance

Permitted interval between dimensional limits

The permitted variation of a dimension, expressed by upper and lower limits or by deviations from a nominal size. The tolerance width is the difference between the upper and lower limits.

Used for cable outside diameters, entry holes, seal sections and groove depths.

Read each deviation with its sign and reference size; asymmetric limits need not be centred on the nominal value. Dimensional tolerance is a design requirement, not measurement uncertainty.

• ISO↗

DIN rail

Standardized equipment mounting rail

A shaped rail used to mount compatible electrical devices, with defined dimensions and mounting relationships; DIN rail is a common family description.

Used for terminal blocks and control components inside cabinets and junction boxes.

Match the precise rail profile and fastening requirements. Protective-earthing use depends on the relevant product and system provisions, not the rail shape alone.

• IEC↗

Displacement seal

Controlled-displacement cable seal

A gland sealing arrangement in which tightening moves a sealing element into a controlled space to develop contact around the cable.

Described in sectional gland drawings and displacement-seal installation instructions.

Check the actual seal geometry, jacket diameter and tightening instructions. The construction name alone does not establish sealing performance or an Ex protection type.

• IEC↗

Double-coaxial method

Double-coaxial electromagnetic test method

An EMC measurement arrangement using defined coupled coaxial regions to characterize transfer impedance or screening attenuation of specified feed-throughs and gaskets.

Used in screening tests of bulkhead components and conductive gaskets.

Check the method's fixture and frequency range and the specimen mounting; a result for one gasket or mounting arrangement cannot qualify a different complete enclosure.

• IEC↗

Double-compression gland

Armoured gland with two sealing or compression zones

A trade description for an armoured gland that acts on the cable inner covering and outer sheath through separate functional zones.

Common in industrial, oil-and-gas and armoured-cable gland catalogues.

Compare actual construction and approval, not the label alone; cable bedding and outer-sheath diameters must fit their respective ranges.

• BSI↗
• IEC↗

Drain plug

Enclosure drainage fitting

A fitted component intended to allow collected liquid or condensate to drain from an enclosure under stated orientation and conditions.

Installed at low points of outdoor, marine or washdown enclosures and junction boxes.

Confirm drainage direction, thread, material, ingress effect and any Ex approval; a drain is not interchangeable with a sealed blanking plug.

• IEC↗
• IEC↗

Drain wire

Cable-screen contact wire

An uninsulated or specially arranged conductor in contact with a cable's conductive screen to facilitate its electrical termination.

Common in foil-screened signal cables and instrument wiring.

Check the required screen-termination method and frequency range; terminating only the drain wire may not provide the same screening as circumferential contact.

• IEC↗
• IEC↗

Drainage slope

Vertical fall relative to horizontal run

The vertical fall along a specified direction divided by the corresponding horizontal run, often expressed as a percentage. For a straight grade, the angle is the arctangent of that ratio.

Used when considering sloped surfaces, cable routes and deliberate drainage paths around enclosures.

State the direction, endpoints and horizontal run. Slope alone does not establish drainage capacity, prevent capillary retention or preserve an enclosure ingress rating.

• ISO↗
• IEC↗

DSC

Differential scanning calorimetry

A thermal-analysis technique that measures a heat-flow difference associated with a specimen and reference during a controlled temperature programme.

Used to examine polymer transitions, melting, crystallization and other thermal behaviour.

Specify method, heating rate, atmosphere and specimen history; a transition measured by DSC is not automatically the component's allowable service temperature.

• ISO↗

Ductility / plasticity

Deformation before fracture and permanent deformation

Plasticity is the ability to undergo permanent deformation after the load is removed. Ductility describes the capacity for plastic deformation before fracture, commonly assessed through tensile elongation or reduction of area.

Used in metal material selection, forming, thread damage and mechanical-failure discussions.

Read the test method, material condition and loading direction. Ductility is not elastic recovery, hardness or a strength rating, and a plastically deformed gland thread should not be treated as an acceptable fit.

• ISO↗

Duplex stainless steel

Ferritic-austenitic stainless steel

A stainless-steel family with both ferritic and austenitic phases, whose useful properties depend on composition and controlled microstructure.

Specified for demanding corrosion or strength duties on suitable metal entry components.

Require the exact grade and fabrication condition and verify phase quality; duplex describes a family and does not establish universal marine suitability.

• ISO↗
• ISO↗

Dust group

Explosive-dust equipment subgroup

A subdivision of IEC Group III equipment addressing combustible flyings, nonconductive dust and conductive dust, commonly identified as IIIA, IIIB and IIIC respectively.

Appears in Ex dust marking and hazardous-area equipment specifications.

Match the dust's characteristics and required equipment marking; a gas group or enclosure IP rating does not replace the dust-group assessment.

• IEC↗
• IEC↗

Dust-tight

Protection against dust ingress

A descriptive term for an enclosure or entry that meets a stated dust-ingress criterion under a defined standard and test arrangement.

Used in IP, NEMA Type and application specifications for dusty industrial environments.

State the actual rating and complete assembled interface; do not translate the phrase directly into an IP or NEMA value without evidence.

• IEC↗
• NEMA↗

Earth fault

Unintended conductive connection to earth

A fault in which a live circuit becomes connected to earth or an earthed part through an unintended path, which may have low or high impedance.

Investigated in damaged cables, wet terminations and insulation failures.

Identify fault-loop and protection requirements for the system; effective sealing and insulation do not replace protective earthing or fault detection.

• IEC↗
• IEC↗

Earth tag

Cable-gland earthing tag

A conductive tag fitted at a cable-gland entry to provide an external point for a bonding or protective conductor connection.

Used with metallic glands on metal or non-metallic enclosures where a defined bonding path is required.

Match gland thread size and fault-current duty, protect against corrosion and verify the complete connection rather than the tag alone.

• BSI↗
• IEC↗

Eddy current

Induced circulating current in a conductive material

Current induced within a conductive body by a changing magnetic field, which can produce losses and heating depending on geometry and material.

Relevant to metallic panels and entries surrounding single-core AC power cables.

Review cable grouping, panel geometry and material properties; a nonmagnetic metal can still support eddy currents.

• IEC↗
• IEC↗

Edge distance / edge ligament

Hole-centre distance and remaining material to a free edge

Edge distance measures from a hole centre to the stated plate edge. The edge ligament is the material remaining from the hole boundary to that edge; for a round hole it is centre distance minus hole radius.

Used in gland-plate layouts and checking space around enclosure entry holes.

State the measuring direction and use the actual hole boundary. Geometric ligament width alone cannot establish bearing, tear-out or plate-strength capacity.

• ISO↗
• ISO↗

Effective leak-test volume

Gas volume participating in a pressure-decay measurement

The connected gas volume whose pressure change is measured during a leak test. It can include the specimen cavity, fixture, tubing and other communicating spaces present during the measurement.

Used to convert pressure decay into a gas-loss estimate.

Determine the volume for the actual valve configuration and fixture. Flexible walls, trapped volumes, thermal drift and changing volume can invalidate a simple rigid-volume model.

• ISO↗
• ISO↗

Effective pressure-loaded area

Area relating a pressure difference to its resultant force

The area appropriate to the selected pressure boundary and force direction. For a uniform pressure difference on a simple projected area, the resultant force is Δp multiplied by that area.

Used in preliminary force estimates on seals, closures and enclosure penetrations.

Identify the pressure on each side and the actual load path. The product outside diameter or visible surface area need not be the effective pressure area.

• ISO↗

Elastic modulus

Stiffness parameter relating stress and elastic strain

A measure of elastic stress-strain response. In a linear uniaxial range, Young’s modulus is stress divided by strain; non-linear materials require a specified tangent, secant or other test-defined modulus.

Used in material deformation estimates and simplified cable or seal interference models.

Identify the material, strain range, temperature and loading rate. An elastomer modulus is not universally constant and must not be equated directly with Shore hardness.

• ISO↗
• ISO↗
• ISO↗

Elastic recovery / rebound resilience

Shape recovery and energy returned after deformation

Elastic recovery is the return toward the original shape after unloading. Rebound resilience is the fraction of impact energy returned in a defined test; a high rebound value does not directly establish low compression set or sustained seal contact.

Used in rubber material comparisons and discussions of gland-seal deformation.

Keep shape recovery, rebound, compression set and stress relaxation distinct. Specify temperature, loading history and test method, then assess the seal under its actual installed compression.

• ISO↗
• ISO↗
• ISO↗

Electric charge

Electrical quantity transferred by current over time

The quantity of electricity transferred through a circuit is the time integral of current, expressed in coulombs. With constant current, transferred charge is current multiplied by elapsed time.

Used in electroplating calculations to relate supplied current and process duration to theoretical deposited mass.

Use measured integrated charge when current varies. Charge is not electrical energy or power, and supplied charge alone does not determine deposit mass without reaction and efficiency information.

• IEC↗
• ISO↗

Electric current

Rate of electric-charge flow

The rate at which electric charge passes through a specified surface, measured in amperes. A current value may describe direct current, an instantaneous waveform or a stated effective value.

Used in conductor voltage-drop, resistance-loss, current-density, bonding and electroplating calculations.

Match DC, RMS or instantaneous values to the formula. Circuit current is not the same as a component current rating or permitted cable ampacity.

• IEC↗

Electric field strength

Electric force per unit charge

The electric field is a vector quantity expressed in V/m. For ideal parallel electrodes with a uniform field, its magnitude is the applied voltage divided by their separation.

Used in preliminary insulation-field calculations and interpretation of material tests.

Edges, voids and material interfaces can produce higher local fields than V/t. Calculated field is not measured dielectric strength or a finished product voltage rating.

• IEC↗
• IEC↗

Electric voltage

Electrical potential difference between specified points

In the circuit conditions considered here, voltage is the electrical potential difference between two specified points, expressed in volts. Its value depends on the reference points and stated polarity.

Used in resistance measurements, voltage-drop calculations, electric-field estimates and connector circuit descriptions.

Distinguish applied, operating, rated and breakdown voltages. For time-varying signals, state whether values are instantaneous, peak or RMS before using them in a formula.

• IEC↗

Electrical conductivity / resistivity

Electrical conduction and its reciprocal material property

Electrical conductivity describes a material's ability to carry current; resistivity describes resistance normalized for geometry and is its reciprocal under corresponding conditions.

Used in metal bonding paths, conductive compounds and electrical-insulation material specifications.

Check units, direction, temperature and measurement conditions; bulk resistivity, surface resistance and assembled contact resistance are different quantities.

• IEC↗
• IEC↗

Electrical isolation

Separation of an electrical conductive path

An arrangement that interrupts or limits conduction between specified circuit parts or conductive structures using an appropriate insulating boundary.

Used in insulated glands, cable-sheath bonding points and electrically separated interfaces.

Identify the separated parts and required voltage duty, and preserve necessary protective bonds; mechanical separation alone does not prove electrical isolation.

• IEC↗
• IEC↗

Electrical leakage current

Unintended current through or across insulation

Current following an unintended conductive path through insulation or across its surface. In a measurement setup, fixtures and connections can provide additional leakage paths alongside the specimen.

Used to interpret insulation-resistance tests of connectors, cables and electrical assemblies.

Separate specimen and fixture contributions and state test conditions. Electrical leakage current is not a gas or liquid leak rate, and an early test current can also contain charging or absorption components.

• IEC↗
• Keithley / Tektronix↗

Electrical resistance

Resistive opposition to electric current

For a resistive DC element at a stated operating point, resistance is the voltage across it divided by the current through it, R = V/I, in ohms. A uniform conductor can also be modelled by R = ρL/A.

Used in conductor losses, bonding paths, connector contact tests and insulation measurements.

Keep resistance distinct from material resistivity and AC impedance. Identify temperature, current path and test conditions; contact and insulation resistance describe different paths.

• IEC↗
• IEC↗
• IEC↗

Electroless nickel plating

Autocatalytic nickel alloy coating

A nickel-alloy coating formed by autocatalytic chemical reduction on a prepared surface without an externally applied plating current. Nickel-phosphorus is one common system; this is distinct from electrolytic nickel deposition.

Used on metal parts where coating distribution or specified surface properties matter.

Specify coating composition, thickness, substrate preparation and any heat treatment. Shape coverage, adhesion, wear and corrosion performance depend on the specified process and conditions; electroless is not a universal quality ranking.

• ISO↗
• ISO↗

Electromagnetic coupling

Transfer of electromagnetic energy between circuits

Interaction that transfers disturbance or signal energy through electric fields, magnetic fields, radiation or shared conductive paths.

Used in investigations of noise between cables, enclosures and connected equipment.

Identify the coupling mechanism, frequency and return path before selecting shielding, separation, bonding or filtering measures.

• IEC↗

Electromagnetic gasket

Conductive gasket for electromagnetic screening

A gasket designed to maintain a conductive screening interface across a joint when installed with the intended compression and mating surfaces.

Used at enclosure seams, panels and screened feed-through interfaces.

Verify contact pressure, material pairing, corrosion and frequency performance; an EMC gasket need not provide the required environmental seal.

• IEC↗

Electromagnetic immunity

Ability to tolerate electromagnetic disturbance

The ability of equipment or a system to operate as intended in the presence of a specified electromagnetic disturbance without unacceptable degradation.

Used in equipment EMC tests and industrial control-system requirements.

Specify disturbance type, test level and performance criterion; good cable screening alone does not establish the immunity of the complete equipment.

• IEC↗
• IEC↗

Electroplating

Electrodeposited metallic coating

A process that deposits metal onto a conductive workpiece acting as the cathode, using an externally supplied current through a suitable electrolyte. Deposition onto the cathode is distinct from reactions at the anode.

Used for nickel and other finishes on brass glands, fittings and connector contacts.

Check coating material, thickness distribution, adhesion and porosity; the process name does not define corrosion protection or electrical-contact performance.

• ISO↗
• Nickel Institute↗

Electropolishing

Electrochemical surface material removal

A controlled finishing process that removes metal electrochemically to modify surface condition, often reducing small asperities on suitable stainless parts.

Used in specialist metal finishing and cleanliness requirements.

Specify the process and resulting dimensions, finish and cleanliness; electropolishing does not correct unsuitable alloy selection or establish every hygiene requirement.

• ISO↗

Electrostatic discharge

Electrostatic discharge

A transfer of electric charge between bodies at different electrostatic potentials, by contact or through an intervening medium.

Considered during electronic assembly, cable handling and electrostatic ignition-risk assessment.

Apply the relevant charge-control and bonding requirements for the environment; ESD-sensitive electronics and explosive-atmosphere ignition risks need different assessments.

• IEC↗
• IEC↗

Elongation

Increase in length under tensile loading

The extension of a specimen relative to its original gauge length, often reported as a percentage at a defined condition such as break.

Used in material datasheets for cable jackets, seals and metal components.

Check gauge length, test speed and conditioning; elongation at break is not an allowable continuous extension for a cable or seal.

• ISO↗
• ISO↗

Embrittlement

Loss of material ductility or toughness

A change that makes a material more prone to brittle cracking or fracture, potentially caused by temperature, ageing, chemicals or manufacturing effects.

Investigated in aged seals, plastic parts and degraded metal finishes.

Identify the mechanism and exposure conditions and assess retained properties; acceptable appearance or stiffness does not prove resistance to brittle failure.

• ISO↗
• ISO↗

EMC

Electromagnetic compatibility

The ability of equipment or a system to function satisfactorily in its electromagnetic environment without introducing intolerable disturbance.

Appears in screened-cable, drive, instrumentation, control-cabinet and machine-system requirements.

Treat the gland as one part of the EMC path; screen preparation, enclosure bonding and installation geometry affect system performance.

• IEC↗

EMC cable gland

Electromagnetic-screen terminating cable gland

A cable gland designed to contact a cable screen or braid and maintain a controlled conductive route through the enclosure entry.

Used on screened cables for drives, instrumentation, automation and other disturbance-sensitive systems.

Match the screen diameter and contact method, not only cable OD; verify material, seal range and the complete enclosure bonding arrangement.

• IEC↗
• IEC↗

EMC Directive

Electromagnetic Compatibility Directive

The EU directive addressing electromagnetic compatibility of equipment within its scope, including requirements for emissions and immunity as applicable.

Used in EU equipment conformity documentation and EMC assessments.

Determine the actual apparatus or fixed-installation obligations; an EMC gland or screened cable does not independently establish conformity of the complete equipment.

• European Union↗

EMI

Electromagnetic interference

Electromagnetic disturbance that can degrade the performance of equipment, a transmission channel or an electrical system.

Used when diagnosing noise, specifying screened cables or reviewing emissions and immunity problems.

EMI describes a disturbance; EMC describes acceptable system behaviour. A gland choice must support the intended screen-termination strategy.

• IEC↗

EMT

Electrical metallic tubing

EMT is a North American thin-wall metallic raceway designation, distinct from flexible conduit and threaded rigid conduit constructions.

Used in electrical raceway specifications and termination-fitting schedules.

Use the correct EMT fittings, installation rules and bonding arrangement; trade-size similarity does not make another conduit fitting compatible.

• UL Solutions↗
• IEC↗

Engineering stress / true stress

Stress based on original or current loaded area

Engineering stress uses applied force divided by the original cross-sectional area. True stress uses the current area at the section of interest; the values differ as that area changes during deformation.

Used to interpret tensile measurements and specimen stress calculations.

State the area basis and deformation stage. A stress calculated at one instant is not automatically tensile strength or yield strength, and local necking requires appropriate area measurement.

• ISO↗
• ISO↗

Enlarger

Cable-entry thread enlarging adaptor

A threaded adaptor whose gland-side connection is larger than the available enclosure entry connection in the stated orientation.

Used when a selected gland body needs a larger interface than the existing panel or enclosure thread.

Verify male and female sizes, sealing faces, thread engagement and clearance; an enlarger can change projection and mechanical leverage.

• IEC↗
• IEC↗

Entry thread

Cable-gland enclosure connection thread

The male or female threaded interface used to attach a gland, adaptor, plug or conduit fitting to an enclosure or gland plate.

Listed in product model codes, dimension drawings and enclosure hole schedules.

Specify the full thread designation, size, pitch or series, tolerance and usable length; nominal gland size does not identify the thread.

• IEC↗
• IEC↗

Environmental stress cracking (ESC)

Environmental stress cracking of polymers

Cracking of a susceptible polymer caused by the combination of mechanical stress and a chemical environment that may not cause the same damage without stress.

Considered for housings, glands and seals exposed to cleaners, oils or other chemicals.

Assess the material in its assembled stressed condition and the actual chemical mixture; a simple unstressed immersion test may miss this mechanism.

• ISO↗

EPDM

Ethylene propylene diene rubber

An elastomer family often selected for compatible water, weather and ozone-exposure sealing duties. Resistance depends on the formulated compound and exposure; these strengths do not imply general oil or fuel compatibility.

Found in gland O-rings, sealing inserts, washers, connector seals and enclosure gaskets.

Check the exact compound, medium, temperature, compression set and ageing evidence. Electrical insulation or weather resistance alone does not establish a complete seal or connector rating.

• ISO↗
• ISO↗
• ISO↗
• IEC↗

Epoxy

Epoxy resin system

A resin family that normally forms a cross-linked thermoset after reaction with an appropriate curing agent; properties depend strongly on formulation and cure.

Used in potting, adhesive bonds, barrier compounds and electrical encapsulation.

Check the complete resin/hardener system, cure schedule, shrinkage and chemical compatibility; an epoxy label alone does not establish fire, pressure or Ex performance.

• ISO↗
• IEC↗

Equal-area equivalent diameter

Diameter of a circle with the same area

The diameter d = √(4A/π) of a circle having the same cross-sectional area A as the selected profile. It replaces area numerically without preserving the original shape.

Used when comparing flat or oval cable area, conductor area and circular-area units.

Do not use it as the maximum physical diameter or as proof of circular-gland sealing. It is also different from hydraulic diameter, which depends on wetted perimeter.

• ISO↗
• IEC↗

Equipment group

Explosion-protected equipment group

A marking category tied to the environment addressed by a scheme: IEC uses Group I for susceptible mines, II for gas atmospheres and III for dust; ATEX uses I for mines and II for other places.

Used in Ex markings, certificates and hazardous-area equipment schedules.

Identify the scheme before interpreting a group number; IEC Group II and ATEX Group II do not describe the same grouping boundary.

• IEC↗
• European Union↗

Equipment protection level

EPL

A designation expressing the level of protection assigned to Ex equipment and the likelihood that it remains capable of protection.

Shown in IECEx and ATEX-related equipment marking and hazardous-area specifications.

Match the EPL to the classified zone and material atmosphere, then confirm protection concept, gas or dust group and temperature class.

• IEC↗

EU-type examination certificate

ATEX EU-type examination certificate

A certificate issued through the relevant ATEX conformity-assessment module confirming examination of a defined equipment type against the applicable requirements.

Used in ATEX equipment documentation and certificate-scope checks.

Review the exact type, schedule, changes and conditions, and obtain the declaration of conformity; the certificate does not replace the complete conformity process.

• European Union↗

Ex d

Flameproof enclosure protection “d”

An explosion-protection concept in which an enclosure withstands an internal explosion and limits transmission to the surrounding atmosphere.

Used on flameproof equipment, cable entries and IECEx or ATEX certificate schedules.

Select glands and stopping plugs covered for the enclosure, cable and installation conditions; flamepath and barrier rules may apply.

• IEC↗
• IEC↗

Ex e

Increased safety protection “e”

An explosion-protection concept applying measures that reduce the probability of excessive temperatures, arcs and sparks in normal service.

Used on increased-safety terminal boxes, motors, luminaires and their certified cable entries.

Use entries permitted by the equipment certificate and verify retention, ingress, temperature and any special installation conditions.

• IEC↗
• IEC↗

Ex i

Intrinsic safety protection “i”

An explosion-protection concept that limits electrical and thermal energy in circuits so ignition is prevented under defined conditions.

Used in instrumentation, sensor and control circuits in hazardous locations.

Cable glands still need the mechanical and environmental functions required by the enclosure; intrinsic safety does not remove entry requirements.

• IEC↗
• IEC↗

Ex p

Equipment protection by pressurized enclosure

An explosion-protection concept that uses a protective gas and controlled internal pressure to prevent a hazardous atmosphere from reaching ignition-capable parts under specified conditions.

Specified in pressurized electrical equipment and hazardous-area system documentation.

Check the full protection designation, purge sequence, pressure monitoring and failure response; adding a vent to an ordinary box does not create Ex p protection.

• IEC↗

Ex t

Protection by enclosure “t”

A dust-ignition protection concept using an enclosure to prevent dust ingress and limit external surface temperatures.

Applied to equipment intended for combustible-dust locations and shown in Ex marking.

Confirm IP rating, dust group, surface temperature, EPL and certificate conditions for the complete entry and enclosure assembly.

• IEC↗
• IEC↗

Explosion-proof cable gland

Cable gland for a certified Ex protection concept

A trade term for a cable gland evaluated for specified explosive-atmosphere protection concepts and installation conditions.

Used in hazardous-area catalogues and project material lists, especially for Ex d and Ex e equipment.

Read the certificate schedule, marking and instructions; no gland is universally suitable for every gas, dust, zone, cable or enclosure.

• IEC↗
• IEC↗

Explosion-protected equipment

Equipment designed for explosive atmospheres

Equipment incorporating one or more recognized protection concepts for use where flammable gas, vapour, mist or combustible dust may occur.

Specified in hazardous-area equipment lists, certificates, markings and inspection records.

Use the complete marking and certificate scope; “explosion proof” is an imprecise trade phrase that may hide different protection concepts.

• IEC↗
• IECEx↗

External thread

Male screw thread

A screw thread formed on the outside surface of a cylindrical or conical component such as a gland entry or adaptor.

Shown on gland, plug, adaptor and connector dimensional drawings.

Match thread family, nominal size, pitch, tolerance and taper with the female entry; visual similarity does not establish compatibility.

• ISO↗
• ISO↗
• ISO↗

Extractables

Substances released under laboratory extraction conditions

Chemical constituents that can be removed from a material or device using defined laboratory extraction conditions, which may differ from actual use conditions.

Investigated in medical material characterization and compatibility of polymers, seals or potting compounds.

Specify extraction media, conditions and the final processed material; extractables and substances actually released during use, or leachables, are related but different.

• ISO↗

Face seal

Seal acting between opposed faces

A sealing arrangement in which a gasket, O-ring or other element seals between facing surfaces rather than primarily around a cylindrical radial interface.

Used beneath gland shoulders, at bulkhead flanges and on enclosure covers.

Verify face flatness, seal position and compression support; thread tightness does not by itself establish the integrity of a face seal.

• ISO↗
• IEC↗

Faraday constant

Electric charge per mole of electrons

The product of the Avogadro constant and the elementary charge, F = N_A e, expressed in C/mol. It relates transferred electrical charge to the amount of electrons in an electrochemical reaction.

Used with molar mass, reaction electron number and current efficiency in theoretical electroplating mass calculations.

Keep the C/mol unit with the constant and use the balanced electrode reaction. The symbol F here denotes the Faraday constant, not mechanical force.

• ISO↗
• NIST / CODATA↗

Fatigue / fatigue life

Damage and life under repeated loading

Fatigue is progressive damage caused by repeated loading; fatigue life is the number of cycles or elapsed duty to a defined failure condition under stated loads.

Assessed in moving cables, metal entry parts and vibration-loaded terminations.

Specify load amplitude, mean load, motion and failure criterion; a cycle count without those conditions cannot establish comparable service life.

• ISO↗
• IEC↗

Fault current

Current resulting from an electrical fault

Current that flows because of an unintended circuit condition, such as insulation failure or a short circuit, with magnitude and duration determined by the system.

Used in protective-device selection and assessment of bonding paths and cable restraints.

Check prospective fault conditions and protective-device clearing time; normal load-current capability does not establish fault-current withstand.

• IEC↗
• IEC↗

Fault-current capacity

Ability to withstand specified fault-current duty

The capability of a conductor or conductive assembly to carry a defined fault current for a defined time without unacceptable thermal or mechanical damage.

Relevant to protective bonds through glands, armour connections and enclosure interfaces.

Require evidence for the actual assembly and duration and coordinate with protection; DC continuity alone does not establish short-circuit withstand.

• IEC↗
• IEC↗

FEA

Finite element analysis

A numerical method that divides a model into elements to approximate responses such as stress, deformation or temperature under specified equations and boundary conditions.

Used in gland-body, panel, seal and thermal design studies.

Check geometry, material laws, contacts, mesh and validation against relevant measurements; FEA output does not independently qualify the manufactured assembly.

• ASME↗
• ISO↗

Feed-through

Electrical connection through a boundary

A component or assembly that passes a conductor or signal through an enclosure or barrier while maintaining specified mechanical, electrical or screening functions.

Used in filtered penetrations, bulkhead connectors and screened enclosure interfaces.

Specify which functions are required; a feed-through is not necessarily hermetic, filtered or rated for a particular pressure or ingress duty.

• IEC↗
• IEC↗

Female connector

Connector half with socket contacts or female interface

A connector designation normally referring to the mating half that contains socket contacts or the defined female mechanical interface.

Used in circular, waterproof and photovoltaic connector descriptions and cable-harness drawings.

Follow the manufacturer’s interface and polarity definitions; shell gender, contact gender and electrical polarity may not use the same naming.

• IEC↗
• IEC↗

Festoon cable

Cable for a suspended travelling loop system

A flexible cable arranged in hanging loops that move with travelling equipment, commonly supported by trolleys along a track or wire.

Used on cranes, hoists and other equipment with a defined suspended cable path.

Check the cable's festoon duty, loop radius, support spacing and terminal anchorage; a general flexible cable may not tolerate the same motion.

• IEC↗
• IEC↗

FFKM

Perfluoroelastomer

FFKM is an elastomer family with a highly fluorinated polymer structure, distinct from ordinary FKM; finished properties depend on the formulation and cure system.

Specified for specialist seals exposed to demanding chemicals or temperatures.

Verify compatibility, compression behaviour and temperature limits for the exact compound; the FFKM family name is not a universal chemical-service approval.

• ISO↗
• ISO↗

Fire-rated cable gland

Cable gland used in a fire-performance assembly

A description for a gland assessed within a stated fire exposure or penetration-sealing arrangement; the meaning depends on the governing test and assembly.

Appears in fire-survival cable systems, compartment penetrations and specialist installation specifications.

Require the tested assembly, exposure, duration and installation details. Flame-retardant material or an IP rating does not establish fire resistance.

• IEC↗
• ISO↗

Firedamp

Flammable mine gas principally associated with methane

A mining term for a flammable gas mixture, principally methane, that can form an explosive atmosphere in susceptible underground workings.

Used in mining equipment group descriptions and specialized hazardous-area requirements.

Check the mine's assessed atmosphere and required Group I equipment marking; ordinary industrial gas-group descriptions do not establish mining suitability.

• IEC↗

FKM

Fluoroelastomer

A fluorinated elastomer family selected for compatible heat, oil and chemical sealing duties. FPM is a designation encountered in older or regional material descriptions; Viton is a particular brand rather than the generic name for every FKM. Regional Type 26 labels also require confirmation of the actual polymer and compound.

Used in special gland seals, O-rings, connector seals and process-environment entry hardware.

Verify the actual polymer type, compound, medium and service limits. Conventional FKM may be unsuitable for amines, strong bases or hot water and steam; specialized resistant polymers need their own evidence. Gas permeability alone does not establish vacuum suitability.

• ISO↗
• ISO↗
• IEC↗
• Chemours↗
• Chemours↗

Flame retardant

Reduced flame propagation characteristic

A material or product characteristic describing performance in a specified flame test, without implying that the material cannot burn.

Used in plastic gland, connector, enclosure and cable material specifications.

Ask for the test method, specimen thickness and classification; do not treat “flame retardant” as a universal fire-safety rating.

• UL Solutions↗

Flamepath

Flame-quenching joint path

A defined joint or passage in flameproof equipment through which gases from an internal explosion can pass while being cooled to prevent ignition of the external atmosphere under the specified conditions.

Inspected on Ex d joints, threaded entries and associated enclosure details.

Preserve specified dimensions, surface condition and assembly instructions; flamepaths must not be modified or treated as ordinary gasket-sealing faces.

• IEC↗
• IEC↗

Flange

Projecting mounting or connection rim

An enlarged rim or plate-like part used to mount, connect or seat components, often with bolts or a gasketed face.

Used on bulkhead entries, cable penetrators and enclosure fittings.

Check hole pattern, stiffness, gasket compression and space for assembly; flange size alone does not establish a pressure or ingress rating.

• IEC↗
• ISO↗

Flat cable

Cable with a non-circular outer profile

A cable whose outer sheath has a flat, oval or ribbon-like cross-section rather than a substantially circular sealing surface.

Used in lighting, appliances, automation, ribbon systems and special harness entries.

Use a seal designed for the actual profile and dimensions; a round-hole compression seal can leave leakage paths around a flat cable.

• IEC↗

Flatness

Geometric flatness of a surface

A form characteristic describing how closely a surface lies within a defined pair of parallel planes, independent of a datum when specified as flatness.

Used for gasket seating faces, gland plates and enclosure joints.

Apply the drawing's tolerance and measurement method; a visually smooth or low-roughness surface can still be too curved for uniform seal compression.

• ISO↗

Flexible metal conduit

Flexible metallic conduit

A conduit construction with a flexible metal structure intended to protect or route conductors under its defined installation requirements.

Used between enclosures, moving equipment and conduit fittings.

Select compatible end fittings and check bending, corrosion and bonding requirements; flexible metal construction does not by itself establish liquid tightness.

• IEC↗
• UL Solutions↗

Floating photovoltaics (FPV)

Floating photovoltaic installation

A PV installation supported by floating structures on a body of water, with site-specific movement, anchoring and environmental conditions.

Used in reservoir and other floating solar-system specifications.

Assess motion, water exposure, cable routing and maintenance access for the actual site; ordinary outdoor component ratings do not automatically cover floating-system duty.

• IEC↗
• IEC↗

FMEA / FMEDA

Failure modes and effects analysis and diagnostic extension

FMEA systematically examines failure modes and their effects; FMEDA extends such analysis with failure-rate and diagnostic information used in relevant safety evaluations.

Used in design-risk review and assessment of safety-related electrical systems.

Define boundaries, failure assumptions and evidence. An analysis is not a test certificate, and FMEDA results alone do not establish a complete safety function's SIL.

• IEC↗
• IEC↗

Frequency

Number of cycles per unit time

For a periodic phenomenon, frequency is the reciprocal of its period and is expressed in hertz. It identifies the repetition rate, not the amplitude of the signal.

Used in wavelength comparisons, transfer-impedance measurements and descriptions of alternating electrical signals.

State the measurement frequency or frequency range and waveform. A shielding or impedance result at one frequency does not establish performance over another band.

• ISO↗
• IEC↗

FTIR / ATR-FTIR

Fourier-transform infrared spectroscopy and ATR sampling

FTIR measures infrared spectral information using a Fourier-transform technique; ATR-FTIR uses attenuated total reflection to obtain information from a defined near-surface region.

Used in polymer identification, contamination analysis and material-comparison studies.

Identify the sampling method and reference spectra and account for additives and surface contamination; spectral similarity alone does not establish a complete formulation.

• ISO↗

Fundamental thread triangle

Untruncated triangle underlying a basic thread profile

The theoretical triangle from which a thread profile is constructed before crest and root truncations are applied. For the 60° ISO metric profile, its height is H = √3 P/2, where P is axial pitch.

Used to derive relationships between basic metric thread diameters and the underlying profile geometry.

Do not treat H as a machining depth. Basic profile dimensions, permitted tolerances and manufactured crest or root shapes are separate requirements.

• ISO↗
• ISO↗

Galvanic corrosion

Corrosion influenced by coupled dissimilar materials

Corrosion arising from electrical contact between materials with different electrochemical behaviour in a shared electrolyte, often accelerating attack on the more active member.

Considered at mixed-metal glands, enclosure panels, washers and marine-adjacent installations.

Assess material pairing, electrolyte, area ratio and coating continuity; electrical isolation must also remain consistent with the required protective bonding.

• ISO↗
• IEC↗

Galvanic series / galvanic couple

Galvanic ranking and coupled material pair

A galvanic series ranks materials by measured corrosion potential in a specified environment; a galvanic couple is an electrically connected pair exposed to an electrolyte.

Used when reviewing mixed-metal interfaces in wet or corrosive service.

Use a series for the relevant environment and assess area ratio and conditions. Rank separation alone does not predict a couple's corrosion rate.

• ISO↗

Gas group

Explosion-protection gas subdivision

A classification grouping gases and vapours by ignition-related characteristics used in explosion-protection equipment selection.

Appears in Ex equipment marking, area-classification records and certificate schedules.

Match the equipment subgroup to the atmosphere and protection concept; a temperature class does not replace the gas-group requirement.

• IEC↗

Gasket

Compressed sealing element between mating surfaces

A gasket is a deformable component placed between surfaces to limit passage of fluid or contaminants when the assembly applies the intended compression.

Used at enclosure covers, gland shoulders, flanges and junction-box interfaces.

Match geometry, compression, surface finish and environmental compatibility; replacing a gasket with an apparently similar sheet can change the assembly rating.

• IEC↗
• ISO↗

Gland plate

Removable cable-entry plate

A panel or plate provided on an enclosure for mounting multiple cable glands, conduit fittings or entry accessories.

Used on control cabinets, switchgear, junction boxes and modular equipment enclosures.

Check material, thickness, hole spacing, stiffness, bonding and sealing; thin or crowded plates can distort during gland tightening.

• IEC↗
• IEC↗

Gland shoulder

Cable-gland body seating shoulder

The enlarged face or step on a gland body that bears against the enclosure, washer or other specified mounting surface.

Shown on gland mounting drawings and panel-thickness checks.

Confirm shoulder clearance and a continuous sealing surface around the entry; nearby edges, welds or paint defects can prevent correct seating.

• IEC↗

Glass transition temperature (Tg)

Temperature range of the glass transition

The temperature region where amorphous polymer segments change from relatively glassy, restricted motion to more mobile behaviour. The reported Tg depends on the material and measurement method; it is not a melting point.

Used in low-temperature flexibility, elastomer compound characterization and DSC test reports.

Check how Tg was measured and the actual sealing or brittleness tests. A Tg value alone does not specify the minimum operating temperature, maximum service temperature or complete gland rating.

• ISO↗
• ISO↗

Glass-fiber content

Glass-fiber fraction in a polymer compound

The amount of glass-fiber reinforcement in a compound, with the basis stated as mass fraction or volume fraction. These fractions are different quantities; common polymer markings such as GF30 indicate glass-fiber content by mass.

Used in reinforced-polyamide grade markings, resin datasheets and moulding specifications.

Confirm the declared basis and grade. Fiber length, orientation, matrix, moisture and processing also affect stiffness, shrinkage and toughness; a higher percentage is not a universal performance ranking.

• ISO↗
• ISO↗

Glass-fiber reinforcement

Glass-fibre-reinforced material

A polymer compound containing glass fibres as reinforcement; fibre content, length and orientation influence stiffness, strength and dimensional behaviour.

Identified on gland bodies, connector housings and resin-grade specifications.

Check the exact grade and fibre content and allow for anisotropy, surface finish and moisture effects; reinforcement does not establish a finished-part rating.

• ISO↗
• ISO↗

Glow-wire / needle-flame test

Glow-wire and needle-flame fire tests

A glow-wire test applies a specified heated element; a needle-flame test applies a small specified flame. They evaluate different ignition and burning responses under controlled conditions.

Used in electrical-component fire-hazard testing and material qualification.

Specify the exact test, severity, specimen and acceptance criteria; a result from one method does not automatically establish performance under the other.

• IEC↗
• IEC↗

Gravitational acceleration

Acceleration used to relate mass and gravitational force

The acceleration associated with gravity, expressed in m/s². Weight force is calculated from mass and the applicable gravitational acceleration; standard gravity is the conventional value used in kilogram-force conversions.

Used in hanging-cable loads, hydrostatic pressure and conversions between mass-based and force-based descriptions.

Keep kilograms and newtons distinct. State whether a calculation uses local gravity or the conventional standard value, especially when converting kgf to SI force.

• ISO↗

H2S

Hydrogen sulfide

H2S is hydrogen sulfide, a toxic and flammable gas that can also create demanding material-corrosion conditions in certain industrial environments.

Appears in sour-service exposure descriptions and hazardous-area or material specifications.

Specify concentration, fluid chemistry and temperature and use the applicable safety and material requirements; a generic corrosion-resistant gland claim does not cover H2S service.

• OSHA↗
• ISO↗

H59 brass

Chinese copper-zinc brass grade H59

A brass grade designation in the Chinese copper-alloy system. It identifies an alloy composition specification rather than one universal strength, corrosion rating or lead content for a finished gland.

Used in brass gland-body, locknut and adaptor material specifications.

Request the applicable grade standard, composition certificate and product condition. Do not infer dezincification resistance, potable-water suitability or equivalence to another national grade from H59 alone.

• SAMR / SAC↗
• ISO↗

Halogen-free

Material statement concerning halogen content

A material or product claim indicating compliance with a stated method or threshold for halogen content rather than a single universal property.

Used in cable, gland, connector and enclosure specifications for smoke or corrosivity-conscious projects.

Request the referenced method and scope; halogen-free does not automatically mean low smoke, flame retardant or suitable for every fire requirement.

• IEC↗
• IEC↗

HALS

Hindered amine light stabilizers

A class of polymer additives used to slow light-induced degradation through chemical stabilization mechanisms; effectiveness depends on formulation and exposure.

Named in UV-stabilized cable-jacket and polymer-grade descriptions.

Require exposure-test data for the actual compound and colour; the presence of HALS does not establish a universal outdoor lifetime.

• ISO↗
• ISO↗

Harmonics

Frequency components at multiples of a fundamental

Sinusoidal components whose frequencies are integer multiples of a fundamental frequency, commonly present in nonsinusoidal current or voltage waveforms.

Considered in power systems, drive installations and electromagnetic disturbance assessments.

Assess the actual spectrum and conductor or equipment heating; a fundamental-frequency current value does not describe every loss or interference effect.

• IEC↗
• IEC↗

Hazardous area

Location with a potentially explosive atmosphere

An area in which an explosive atmosphere is present or may be expected in quantities requiring special equipment and installation precautions.

Defined in area-classification drawings, equipment schedules and installation specifications.

Obtain zone, gas or dust group, temperature class and environmental details before selecting the gland and conformity route.

• IEC↗
• IEC↗

Heat flow rate

Thermal energy transferred per unit time

The rate at which heat is transferred, measured in watts, where one watt is one joule per second. It describes thermal power rather than an accumulated quantity of heat.

Used in enclosure heat balances and heat-transfer estimates through a surface or layer.

Define the heat path and steady or transient conditions. Heat-flow rate is not heat flux, stored energy or a direct measure of component temperature.

• ISO↗

Heat flux

Heat-flow rate per unit area

The heat-flow rate crossing a surface divided by its area, commonly expressed in W/m². A single Q̇/A value represents an average over the stated area.

Used to compare heat transfer through enclosure walls, insulating layers and exposed surfaces.

Identify the area and direction of transfer. An average heat flux can conceal local hot spots and cannot determine temperature without the heat-transfer conditions.

• ISO↗

Heat sink / thermal management

Heat-dissipating component and heat-control strategy

A heat sink provides a path and surface for transferring heat; thermal management is the broader control of heat generation, transfer and component temperature.

Used in sealed electronics, connector heating and junction-box assembly design.

Assess the complete thermal path, ambient conditions and internal losses; an enclosure vent or conductive gland is not independently a thermal-management solution.

• IEC↗
• ISO↗

Hermeticity

Gas-tightness to a stated leakage criterion

A description of a sealed boundary's resistance to gas passage, normally established by a specified leak test and acceptance limit.

Used for specialist feed-throughs, cable penetrators and sealed electrical packages.

Require the test gas, pressure, temperature and maximum leak rate. Hermeticity is not established by an IP water-ingress rating.

• ISO↗

Homogeneous material

Material that cannot be mechanically separated into different materials

In RoHS terminology, a material of uniform composition throughout or a combination that cannot be mechanically disjointed into different materials by actions such as cutting or abrasion.

Used when applying restricted-substance concentration limits to cable, connector and coating materials.

Assess the relevant material level rather than averaging over the complete product; compliance evidence must match the actual constituent materials.

• European Union↗

Hydrolysis

Chemical degradation involving water

A chemical reaction in which water breaks susceptible bonds, potentially changing a polymer's molecular structure and mechanical properties.

Considered for polyesters, some polyurethanes and other materials exposed to moisture and heat.

Assess the exact material, temperature and exposure duration; moisture uptake and hydrolysis are different mechanisms and need different evidence.

• ISO↗
• ISO↗

Hydrophobic membrane

Water-repellent gas-permeable vent membrane

A porous membrane designed to pass gas while resisting liquid-water entry under its declared pressure and environmental conditions.

Used in enclosure vents, pressure-equalization plugs, sensors, luminaires and outdoor junction boxes.

Check airflow, water-entry pressure, contaminant exposure, orientation and service life; hydrophobic does not mean impermeable in every condition.

• IEC↗
• IEC↗

Hydrostatic pressure

Pressure due to a stationary fluid column

The pressure contribution produced by the weight of a fluid above a point, dependent on density, gravity and vertical height.

Used when reviewing submerged entries, liquid-filled equipment and immersion test conditions.

State depth, liquid and duration, and include other pressure sources; a quoted water depth does not cover pressure cycling or every mounting arrangement.

• ISO↗
• IEC↗

IEC 60079

Explosive-atmospheres standards series

The IEC standards series covering general requirements, protection concepts, selection, installation, inspection and related Ex subjects.

Referenced in IECEx certificates, ATEX technical files and hazardous-area project specifications.

Identify the exact part and edition; citing only the series number does not define the product or installation requirements.

• IEC↗
• IEC↗

IEC 60529

Degrees of protection provided by enclosures (IP Code)

The IEC standard defining the IP classification system and tests for protection against access, solid objects and water.

Used for cable glands, connectors, junction boxes, enclosures and complete equipment assemblies.

State the complete IP code and test configuration; a component rating does not automatically establish the assembled enclosure rating.

• IEC↗

IEC 61984

Connectors — Safety requirements and tests

An IEC connector safety standard covering requirements and tests where a more specific connector product standard does not supersede it.

Referenced for industrial circular and multipole connector design, testing and documentation.

Confirm whether the connector is within scope and whether a sector-specific standard, such as IEC 62852 for PV, also applies.

• IEC↗

IEC 62444

Cable glands for electrical installations

The principal IEC product standard specifying requirements and tests for cable glands used with electrical installations.

Referenced in gland datasheets, test reports, project specifications and conformity documentation.

Use the declared cable type, sealing and retention ranges, materials and test classification; the standard number is not a model certificate.

• IEC↗

IEC 62852

PV DC connector safety standard

The IEC product standard for connectors used in direct-current photovoltaic systems, including construction, safety and test requirements.

Referenced in solar connector datasheets, module and array documentation and PV project specifications.

Confirm rated voltage, current, cable range, temperature, mating compatibility and installation method for the exact connector system.

• IEC↗

IECEx

IEC System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres

An international conformity-assessment system using IEC 60079 standards for certified Ex equipment, services and personnel schemes.

Appears on certificates, online certificate records and specifications for internationally traded hazardous-area equipment.

Verify the online certificate, schedule, model, marking and conditions; IECEx is a scheme, not a protection concept by itself.

• IECEx↗

Ignition source

Potential cause of ignition

A source of sufficient energy or temperature to ignite a relevant combustible atmosphere under the applicable conditions, including electrical and nonelectrical mechanisms.

Considered in hazardous-area risk assessment and equipment protection design.

Assess the actual substance and operating or fault conditions; removing one electrical ignition mechanism does not address every possible source.

• IEC↗
• European Union↗

Impact resistance

Resistance to specified mechanical impact

The ability of a component or enclosure to withstand a defined impact test without losing the performance criteria stated by the standard.

Used in gland, connector, conduit, junction-box and hazardous-area product testing.

Compare impact energy, temperature, mounting and acceptance criteria; an IK code or test value must be tied to the complete tested assembly.

• IEC↗
• IEC↗

Inductance / capacitance

Inductance and capacitance

Inductance relates magnetic flux linkage to current; capacitance relates stored electric charge to voltage between conductors. Both can affect frequency-dependent cable and termination behaviour.

Used in screen-lead, connector and interference-path analysis.

Include geometry and frequency-dependent circuit behaviour; inductance and capacitance are distinct quantities and cannot be inferred from DC resistance alone.

• IEC↗
• IEC↗

Infrared thermography

Infrared thermography

A technique that uses detected infrared radiation to estimate and map surface-temperature-related information under a stated measurement model.

Used to investigate heating at electrical connections, enclosures and power-cable terminations.

Account for emissivity, reflections, viewing conditions and load; a thermal image is not a direct measurement of every internal temperature or contact resistance.

• ISO↗

Ingress protection

Protection against access, solids and water entry

The degree of protection provided by an enclosure against access to hazardous parts and ingress of solid objects or water.

Used for glands, connectors, boxes, conduit entries and complete electrical equipment.

Review the complete IP code, mounting and mating state; component ratings do not combine automatically into an enclosure result.

• IEC↗

Inner sheath

Cable bedding or inner covering

A polymeric cable layer beneath armour or the outer sheath that surrounds the laid-up cores and can form an inner sealing surface.

Important in double-compression, barrier and armoured cable-gland preparation.

Measure the actual inner-sheath or bedding diameter and confirm whether it is continuous, extruded and suitable for the declared seal.

• BSI↗
• IEC↗

Insert

Connector insulating contact carrier

The insulating connector component that positions and separates contacts while maintaining the defined interface and electrical distances.

Used in circular and waterproof connector shells, often with keyed arrangements and multiple contact layouts.

Match insert arrangement, contact type, voltage, current and keying; identical shell sizes can contain incompatible inserts.

• IEC↗

Insulated cable gland

Cable gland incorporating electrical insulation

A gland assembly designed to separate specified conductive parts electrically, for example a metallic sheath from an enclosure at a particular bonding point.

Used in power-cable sheath-bonding systems and installations requiring controlled electrical isolation.

Identify exactly which parts are isolated and the required dielectric duty. A plastic exterior alone does not prove isolation of the whole entry assembly.

• IEC↗
• IEC↗

Insulation coordination

Coordinated selection of electrical insulation

The process of matching clearances, creepage distances and solid insulation to electrical stresses and conditions such as overvoltage, pollution and altitude.

Used in connector and low-voltage equipment design and selection.

Evaluate the complete interface and operating environment; rated voltage alone does not determine every necessary insulation distance or test.

• IEC↗

Insulation resistance

Resistance measured across an insulating path

The electrical resistance between defined conductive parts separated by insulation, measured at a stated voltage and condition.

Checked on connectors, cables and sealed electrical assemblies.

Specify test voltage, humidity, temperature and measurement time; a high insulation-resistance value does not replace dielectric withstand or creepage checks.

• IEC↗
• IEC↗

Internal thread

Female screw thread

A screw thread formed on the inside surface of a hole, hub or adaptor intended to receive a matching external thread.

Shown on enclosure entries, adaptors, reducers and connector accessories.

Confirm thread form, size, pitch, tolerance, depth and taper; an oversized clearance hole is not an internal thread.

• ISO↗
• ISO↗
• ISO↗

Intumescent seal

Heat-expanding fire-sealing material

A seal material formulated to expand when heated, helping close an opening or protect a penetration under specified fire conditions.

Used in firestop systems, cable transits and some fire-performance entry assemblies.

Check expansion behaviour and the tested wall, cable and opening arrangement. Intumescence alone does not establish a penetration's fire-resistance classification.

• ISO↗

IP54

Ingress Protection 5–4

An IP classification indicating dust-protected performance and protection against splashing water under the IEC 60529 test definitions.

Used on indoor or sheltered equipment, junction boxes, connectors and cable-entry assemblies.

Confirm that the assembled interface achieves the declared rating and that splashing, not immersion or water jets, matches the application.

• IEC↗

IP65

Ingress Protection 6–5

An IP classification indicating dust-tight performance and protection against water jets under the IEC 60529 test definitions.

Common on outdoor equipment, control boxes, cable glands and industrial connector assemblies.

Do not interpret IP65 as immersion protection; verify mounting, cable seal, entry seal and all enclosure penetrations together.

• IEC↗

IP66

Ingress Protection 6–6

An IP classification indicating dust-tight performance and protection against powerful water jets under defined IEC 60529 tests.

Used for exposed industrial, washdown-adjacent and outdoor equipment where powerful jets are part of the requirement.

Check the actual cleaning pressure, distance, temperature and chemicals; IP66 does not automatically cover high-temperature close-range washdown.

• IEC↗

IP67

Ingress Protection 6–7

An IP classification indicating dust-tight performance and protection against temporary immersion under defined IEC 60529 conditions.

Used on connectors, glands, boxes and field equipment that may be temporarily submerged.

Confirm depth and duration from the declared test; IP67 does not define continuous immersion or every dynamic-water condition.

• IEC↗

IP68

Ingress Protection 6–8

An IP classification indicating dust-tight performance and protection for continuous immersion under conditions agreed for the product.

Frequently specified for outdoor, buried, marine-adjacent and submerged cable-entry products.

Obtain the manufacturer’s depth, duration, cable and mounting conditions because IP68 test severity is not fixed by the code alone.

• IEC↗

IP69

Ingress Protection 6–9

An IP classification indicating dust-tight performance and protection against high-pressure, high-temperature water jets under defined testing.

Used in food equipment, vehicles and machinery exposed to demanding close-range cleaning.

Verify temperature, pressure, spray geometry, seal material and cleaning chemicals; IP69 is not a blanket hygiene or corrosion claim.

• IEC↗

IP69K / IPX9K

Road-vehicle high-pressure hot-water ingress marking

IPX9K identifies a road-vehicle hot-water high-pressure jet test with solid-object protection unspecified by X. IP69K is a commonly used combined dust/water description whose exact governing standard must be checked.

Appears in washdown specifications and road-vehicle component catalogues, including ISO 20653 markings such as IP6K9K.

Require the full marking and test standard. Do not equate a K-suffix road-vehicle classification with IEC 60529 IP69 or with immersion resistance.

• ISO↗
• IEC↗

Irradiance / albedo

Incident radiant power density and surface reflectance

Irradiance is incident radiant power per unit area; albedo describes the fraction of incident radiation reflected by a surface under stated conditions.

Used in PV output estimates, bifacial-module assessment and site modelling.

Specify the relevant spectrum, geometry and time basis; albedo is a reflectance fraction and must not be treated as an irradiance value.

• IEC↗
• ISO↗

Joint preload

Initial clamping load in a joint

The force established in a joint during assembly that holds mating surfaces together before external service loads are applied.

Used in fastener calculations and assessment of gland mounting or sealing compression.

Relate the specified tightening method to material, friction and joint stiffness; torque is an indirect means of creating preload, not the preload itself.

• ISO↗

Joule heating / resistive power loss

Electrical power converted to heat by resistance

Resistive heating converts electrical energy into thermal energy. For DC current through a resistance, the power is I²R; energy is the time integral of that power.

Used in conductor-loss, bonding-path and connector-heating estimates.

Use resistance at the relevant temperature and suitable RMS and AC-resistance values for AC work. Power loss alone cannot predict temperature rise without the thermal conditions.

• IEC↗
• IEC↗

Junction box

Enclosure for electrical connections

A box or enclosure intended to contain, protect and provide access to electrical connections or connecting devices.

Used in building, industrial, outdoor, solar and hazardous-area wiring systems.

Select enclosure rating, material, dimensions, terminals and entry pattern together; drilled gland entries affect the complete assembly.

• IEC↗
• IEC↗

Keying

Connector polarization and coding feature

A mechanical feature that permits mating only in a defined orientation or prevents mating with an incompatible connector variant.

Used in circular, rectangular, waterproof and photovoltaic connector systems.

Match the keyway, coding and insert arrangement; never force similar shells together or assume colour alone controls compatibility.

• IEC↗
• IEC↗

Knockout

Removable preformed enclosure opening

A defined section of an enclosure wall intended to be removed to create an entry opening for compatible wiring hardware.

Found on junction boxes, cabinets and North American electrical enclosures.

Remove only the intended section and inspect the resulting opening; use fittings compatible with its actual size and restore closure of unused openings.

• IEC↗
• UL Solutions↗

Knudsen diffusion

Gas transport dominated by collisions with pore walls

A diffusion regime in which gas molecules collide more often with pore walls than with one another, relevant when the mean free path is large relative to pore dimensions.

Used in specialist analysis of porous membranes and low-pressure gas transport.

Check pore scale and gas pressure before applying the model; ordinary bulk airflow relations may not describe this regime.

• ISO↗
• NASA↗

Labyrinth seal

Seal using a restricted indirect passage

A sealing arrangement that uses a sequence of turns, gaps or chambers to impede passage of fluid or contaminants rather than relying solely on a contacting seal.

Used in protective entries, moving interfaces and enclosure design.

Check orientation, clearance and the intended exposure; a labyrinth can reduce entry without providing a hermetic or immersion-rated boundary.

• IEC↗
• ISO↗

Leak rate

Measured leakage per unit time

The amount of test fluid passing a boundary per unit time under stated conditions, expressed with the appropriate mass-flow, volumetric-flow or pressure-volume units.

Reported in pressure-decay, tracer-gas and sealed-component qualification tests.

State fluid, pressure difference, reference conditions and units; distinguish joint leakage from permeation through an intact material.

• ISO↗

Leak-rate reference conditions

Pressure and temperature used to state a gas leakage quantity

The stated gas pressure, temperature and other conditions to which a reported leakage quantity refers. A volumetric gas-flow value changes with its reference state even when the transferred gas amount is unchanged.

Used when converting pressure-decay results and comparing gas leakage specifications.

Specify absolute reference pressure and temperature, gas and flow convention. Standard litre or sccm labels need an identified reference state; test pressure is a separate condition.

• ISO↗
• ISO↗

LFMC / LFNC

Liquidtight flexible metal and nonmetallic conduit

LFMC identifies liquidtight flexible metal conduit; LFNC identifies liquidtight flexible nonmetallic conduit under North American wiring classifications. Their construction and bonding provisions differ.

Shown in conduit schedules and North American equipment wiring specifications.

Match fittings to the actual conduit designation, trade size and duty; a liquidtight conduit system requires compatible fittings and correct assembly.

• UL Solutions↗
• IEC↗

Lightning protection zone (LPZ)

Lightning protection zone

A region defined by lightning-related electromagnetic conditions and boundary measures in a coordinated lightning-protection concept.

Used in building and equipment protection layouts, including cable crossings between zones.

Identify the actual zone boundary and required bonding or surge protection; a cable-entry location does not independently create a protection zone.

• IEC↗

Linear mass density

Mass per unit length

The mass of a specified length divided by that length, commonly given in kg/m or kg/km. Multiplying by cable length gives mass; multiplying that mass by g gives its gravitational force.

Used in hanging-cable, pulling and support-load estimates.

Use the complete cable construction and consistent length units. Do not substitute material density or treat a mass in kilograms as a force in newtons.

• ISO↗
• Southwire↗

Link box

Power-cable sheath bonding link enclosure

An enclosure containing specified sheath or screen bonding links and, where designed, sheath-voltage limiting devices for a power-cable bonding system.

Used at cable joints and terminations in single-core power-cable installations.

Follow the engineered bonding diagram, insulation levels and inspection arrangements; changing links or gland isolation can alter current and sheath-voltage behaviour.

• IEC↗
• IEC↗