A cable-gland pull-out test measures how an identified gland, cable and enclosure entry respond to a specified axial load. Measure force, elapsed time, local movement and physical changes using the governing method and acceptance limits. An aligned fixture and suitable verified instruments help distinguish an assembly failure from a setup problem.
Before loading, establish the exact cable construction and diameter, gland size, mounting and assembly method. The governing requirement supplies conditioning, load sequence, duration, movement limits and inspection criteria. Keeping those conditions consistent makes the result interpretable; changing them during the run changes the question the test answers.
Key takeaways
- Test the complete gland-and-cable configuration rather than a broad family name.
- Use a representative enclosure entry and pull along the cable centreline.
- Measure cable slip separately from gland movement at the panel.
- Force and displacement systems must be verified over the ranges used.
- Compare the first physical change with force and time, and distinguish a setup fault from an assembly failure.
Choose the applicable test method and limits
Pull testing may be used to qualify a product, check a supplied lot, assess an assembly process, compare a change or investigate a failure. The purpose determines the applicable method and acceptance values. IEC 62444:2010 covers complete glands as supplied; a certificate schedule, project specification, drawing or approved test plan may impose another requirement.
IEC 62444 selection guide explains complete-gland selection. For the pull test, use the applicable document, edition and test reference to obtain load, hold time, rate, movement limit and sample count, including any approved additions. There is no single set for every gland.
Comparing supplier lots may require the same control cable and assembly method. Assessing a new seal or tightening process may require an unchanged baseline product and fixture. These comparisons answer different questions, so results from unlike specimen populations should not be combined.
| Test purpose | Conditions that make the result meaningful | What it can tell you |
|---|---|---|
| Product qualification | Variant, cable-range positions, required method, conditioning, sample plan and acceptance limits | Whether the identified configurations meet those requirements |
| Supplied-lot check | Purchased part, lot, control cable, assembly instruction and sampling rule | Whether the sampled lot meets the applicable receiving criteria |
| Assembly-process assessment | Parts, cable, tools, settings, assembly instruction and inspection method | Whether that process produces the required assembled result |
| Change comparison | Baseline configuration, changed item, comparison method and affected test scope | What changes with the named material, tool, supplier, drawing or process |
| Failure investigation | Returned assembly, service history, original condition and diagnostic sequence | The likely movement source and correction for that assembly |
A qualification load is not automatically an allowable service load. Equipment design also considers supports, routing, acceleration, vibration, accidental pull, installation handling and terminal protection. I use the test for the retention requirement assigned to this assembly, while checking those service loads separately.
Use a specimen that represents the cable entry
The specimen includes the actual gland, cable, entry, accessories and assembly condition. Its full part number, size, material, seals, grip and supplied condition identify the contact system being tested. For armour, type, dimensions, preparation length, clamp parts and order matter. For an unarmoured gland, the jacket surface touching the seal or grip matters.
Cable construction, core count, conductor size, armour or screen and jacket define the specimen alongside its manufacturer and designation. Measure OD at the gripping section rather than relying on a printed nominal value; lot, cut length and condition identify which supplied cable was tested. cable-gland clamping-range guide explains the relevant surface and construction checks.
Use range-boundary samples where the method or plan requires them. Minimum and maximum diameters can load a compression seal differently. Ovality, corrugation, braid, soft jackets, contamination and temperature also change contact. For visibly non-circular cable, measurements at several rotational positions reveal the profile the grip will meet.
Inspect the intended seal and grip sections before assembly. Cuts, flats, mould lines, steps, armour damage, debris, lubricant and cleaning residue may change contact. Use only permitted preparation. If a defect is deliberately studied, treat it as the test variable rather than mixing it unnoticed into ordinary qualification samples.
Assemble the gland in a representative entry
Use the entry arrangement specified by the plan. Reproduce the relevant hole or female thread, panel material and thickness, seating face, washer, O-ring, earth tag, adaptor, locknut and usable thread. I check whether the fixture changes the movement being assessed. A thick plate can hide movement in a thin wall; an overly flexible plate can add movement outside the cable-to-gland joint.
The panel stack, orientation, assembly order, tools, tightening endpoint and counterhold define the mounting condition. cable-gland tightening guide explains how torque depends on the joint, materials, lubrication and tool geometry. Use the current instructions for the chosen gland rather than transfer one torque across sizes or materials.
Before loading, mark cable against compression nut and body or locknut against panel. Also measure initial distances from fixed points where displacement is an acceptance item. I use these references to distinguish cable slip through a stationary gland from movement of the whole gland at the panel.
Apply the specified temperature, time, humidity, fluid or other conditioning and check what the specimen actually experiences. When retention follows another test, keep the same specimen and sequence so cumulative exposure is represented in the result.
Align the fixture and isolate two movement paths
Apply force along the cable axis with a stable reaction at the panel. Align grip, cable, gland bore and fixture as the method requires. Keep the free cable straight. I place the grip far enough away to avoid local jacket damage near the gland, while using only the method’s stated free length.
ASTM E1012-19 explains how misalignment can add unintended bending to axial-force results. It can help commission the fixture even when another document governs the gland test. I recheck alignment after changing grips, load cells, adapters, panel fixtures or specimen geometry. Correct cable bowing, plate rotation, clamp opening or gland side-load before the formal run.
Local displacement is movement measured across the joint being checked. Crosshead travel, the testing machine’s moving-head travel, also includes elastic frame movement, grip seating, cable stretch and fixture movement. It may not equal cable slip. I use a local scale, indicator, sensor or optical reference with the specified resolution and accuracy. Monitor cable-to-gland and gland-to-panel movement separately.
Before testing the first specimen, move a setup piece through the planned motion at low force. I check for binding, grip contact with the gland, snagging sensors or cables, and panel movement. Guard the area because stored energy, a released cable or a broken fixture can move suddenly.
Verify the force and displacement channels
Verify each measuring system in the direction and range used. ASTM E4-24 covers static or quasi-static machine force calibration and verification, including the indicator. NIST’s force-transducer calibration service can calibrate a sensor and customer readout together. I keep that pair together when relying on a system calibration.
Choose capacity that covers the required load within the verified range and safe machine limit. Check that the load cell, machine, indicator and acquisition channel are covered by the applicable calibration or verification, with suitable range, resolution and uncertainty. After mounting the fixture, confirm zero, sign and units.
ASTM E2309/E2309M-20 covers displacement-system verification for material testing machines. The local sensor and readout need range and resolution suitable for the permitted movement. Its mounting and reference points determine which joint movement it measures.
| Measurement or check | What makes it usable | What the result should show |
|---|---|---|
| Axial force | Correct direction, verified range, zero, units, overload limit and acquisition channel | Force versus time, the required peak or held load, and interruptions |
| Cable-to-gland movement | Stable local reference, suitable resolution, initial position, travel range and clear view | Movement versus time and the first change at the cable marks |
| Gland-to-panel movement | Panel/frame reference, initial body and locknut positions, stable reaction | Movement and final condition of the body, locknut, panel, washer or thread |
| Elapsed time | Common clock or synchronized acquisition and correct sample interval | Load transitions, hold period, first event, unloading and end time |
| Visual observations | View of the identified specimen, lighting, scale and unobstructed interfaces | Initial, event where safe, and final conditions of the same assembly |
Choose resolution before testing. A ruler or distant camera may miss a small allowed movement; extra displayed digits do not improve accuracy. I select the method from tolerance, laboratory capability, expected travel, viewing access and uncertainty needed for the decision.
Apply the specified pull sequence
The governing requirement supplies the load, rate, duration, unloading sequence and tolerances. Establish them before testing the first specimen. The following steps explain the setup and observations; they do not supply missing test values.
- Check the intended specimen, cable-range position, preparation, assembly, conditioning and required sample order.
- Mount the panel fixture, grip the cable at the specified free length and align it with the force axis.
- Connect force and local-displacement measurements; check ranges, units and zeros.
- Establish the initial cable-to-gland and gland-to-panel marks or reference distances.
- Close the guard and clear the hazard zone. Use only the seating or preload step specified by the method.
- Apply the required force sequence within its rate or time tolerance. Do not pause, regrip or retighten unless the method permits it.
- Watch both interfaces. Relate force and time to the first slip, gland movement, panel deformation, jacket or armour damage, separation or other defined event.
- Maintain the required force or continue to the specified endpoint, measuring actual force, duration and movement.
- Unload as specified, allow the required recovery time and inspect residual movement and final condition.
- Keep the specimen intact until the required post-test inspection is complete.
A machine or sensor limit, interlock, power loss or unsafe condition may interrupt the test. The force, time and reason for stopping determine whether the required sequence can still be interpreted. Do not resume from an unknown state and present partial runs as one continuous result.
For repeated loading, define waveform or sequence, frequency or timing, cycle count, rest periods, temperature and endpoint. One increasing pull and cyclic loading answer different questions. I follow the assigned method rather than add cycles informally.
Separate an invalid run from a failed assembly
An invalid run has a setup, instrument or procedure problem that prevents interpretation of the required result. Movement or damage within the correctly tested assembly is a specimen outcome. I keep this distinction clear: genuine slip should not be dismissed as a fixture problem, and a misaligned or overloaded setup should not be counted as product failure.
| Observation | What it means | What to check next |
|---|---|---|
| Cable slips through a stationary gland during the correct sequence | Assembly outcome | Force, time, movement and condition against the stated acceptance rule |
| Gland body or locknut moves at the representative panel | Assembly outcome | Threads, panel, accessories, seating and assembly condition |
| Jacket tears at the gland or armour pulls from its clamp | Assembly outcome | First event, cable preparation, failed region, parts and final condition |
| Cable breaks at the remote grip outside the assessed zone | Usually invalid for gland retention | Stop; inspect grip and break location, correct the setup and use a new specimen as required |
| Panel fixture rotates, bends beyond its allowed condition or releases | Invalid if the intended reaction is lost | Restore and verify the fixture; use a new specimen where required |
| Required force or displacement data clip, drop out or leave the verified range | Required result cannot be interpreted | Check raw data, correct the channel fault, restore verification and repeat as permitted |
| Unplanned retightening or regripping interrupts the specified sequence | Procedure departure | Determine repeat requirements under the laboratory’s applicable method and deviation rules |
If classification is uncertain, preserve the specimen, raw data, photos and machine state before disassembly. I examine force and movement traces together. A force plateau, where force levels off, may coincide with slip, grip seating, panel movement, material yielding or machine control. Local readings and images identify the event.
For example, a plateau with an opening cable witness mark and stationary panel mark indicates cable-to-gland movement. If both local marks stay fixed, look elsewhere in the machine or free cable span. I compare the synchronized traces and images before classifying the run.
A repeat must follow the applicable retest method. Use a new sample when prior loading, marking, cutting, compression or displacement could change the next result. Inspect the original specimen first: using it again without an explicit method would mix previous loading and reassembly effects into the repeat.
What does a passing pull test tell you?
A pass supports the assembly, method, conditioning and requirement represented in the test. That includes gland and component variants, cable construction and range, preparation, panel entry, accessories, tools and tightening. It also depends on the conditioning and sampling or qualification method. Changing those conditions may change the retention result.
Changes to cable supplier, jacket, armour, seal, grip, material or manufacturing geometry may affect contact and load transfer. Lubricant, tools, torque, panel thickness, washer stack, adaptor and assembly instructions matter too. Reassessment or retesting depends on the changed item and the retention path it affects, using the original specimen and test conditions for comparison.
Pull-out resistance does not establish other entry functions. The strain-relief and sealing guide distinguishes retention from cable and wall sealing. IEC 60529 covers enclosure ingress protection (IP) for the evaluated entry and conditions. I separately check mounting, bonding, electromagnetic compatibility (EMC), hazardous-area construction, bending and support where required.
For U.S. workplaces within its scope, OSHA 29 CFR 1910.305(g)(2)(iii) requires flexible cords and cables to be connected to devices and fittings so strain relief prevents pull from being directly transmitted to joints or terminal screws. An installed cable route therefore still needs suitable supports and terminal protection. A laboratory pull result does not authorize the gland to carry every service load in the route.
For a product comparison, cable-gland pull-out strength comparison guide uses matched specimens and the first physical change. Keep that comparison separate from qualification unless the applicable acceptance document explicitly connects them. The chosen endpoint answers a different question from meeting a prescribed validation requirement.
Read the result with its test conditions
A useful report connects the result to the complete specimen and test method. Assembly details, photographs, measurement channels, inspection findings and any deviations need to describe the same tested item. That connection lets you understand the result or reproduce the relevant comparison.
Look for these details when interpreting a result:
- Requirement: purpose, applicable document and edition, test reference, required values, acceptance limits and any authorized deviations.
- Specimen and conditioning: gland, cable, entry, accessories, lot, preparation, test location and conditions, and sample order.
- Assembly: instruction, tools, tightening setting or endpoint, counterhold and initial movement references.
- Measurement system: frame, load cell, grips, fixture, force and displacement channels, ranges, calibration or verification status and data rate.
- Geometry: alignment, free cable length, grip position and local sensor references, shown in a setup drawing or photographs.
- Observed response: actual load sequence, elapsed time, force, local movement, first change, required peak or held values and interruptions.
- Final condition: cable, gland, thread, locknut, washer, panel, seals, grip, armour and jacket after the test.
- Interpretation: each acceptance result, whether the run was valid, deviations and the basis for any repeat.
Force-time and movement-time data can reveal slip, mounting motion, fixture failure and whether the hold duration was reached. Units, sample rate, channel identity, filters and processing define those traces. Corrections or excluded values need an explanation so the response remains interpretable. Maximum force and “pass” alone cannot show the full event.
Conclusion
A valid pull-out test starts with the applicable method and limits, a representative gland, cable and entry, and the specified assembly and conditioning. Align the axial pull, verify force and local-movement measurements, guard the setup and apply the prescribed sequence. These conditions let the measured response describe the intended cable-entry assembly.
Watch cable slip and gland-to-panel movement separately, relating the first change to force and time. A genuine assembly event is a specimen result; a setup or measurement fault may prevent interpretation. Use a passing result only for the represented parts, preparation, mounting and conditions, and reassess changes affecting the retention path. Other gland functions and service loads still need their own checks.
Cable gland pull-out resistance test FAQs
What pull-out force should be used for a cable gland assembly?
Use the force from the product standard, certification schedule, project specification, drawing or approved test plan applicable to the exact assembly. Its edition, test reference, rate or timing, duration, movement limit, specimen count and acceptance rule define the result. One force cannot be assigned to every gland size or cable construction.
Is crosshead travel enough to measure cable slip?
Usually not by itself. Crosshead travel can include frame compliance, grip seating, cable stretch, fixture movement, and actual slip. Measure locally between the cable and gland when cable movement is an acceptance item, and monitor the gland against the panel separately so the two movement sources are not combined.
Can the same cable gland assembly be retested after a pull test?
Only when the applicable method or an approved disposition permits it. Prior loading, cable marking, jacket damage, seal compression, thread movement, and reassembly can change the next result. Preserve the first specimen for inspection and use a new identified assembly when the method requires an independent repeat.
What makes a cable gland pull-test run invalid?
A run is invalid when a fixture, instrument, safety interruption, or procedure departure prevents a required result from being interpreted. Examples include loss of the reaction fixture, a measurement channel outside its verified range, or cable failure at an unintended remote grip. Cable slip, gland movement, or damage within the specified assembly is a specimen outcome, not automatically an invalid run.
Does passing a pull-out test confirm the cable gland’s IP rating?
No. The pull test addresses the stated retention requirement for the tested assembly. An IP classification requires the applicable enclosure-protection test on the identified enclosure-entry arrangement and conditions. Retention, cable sealing, enclosure sealing, mounting, bonding, EMC, and service routing should be checked under their own requirements.
Sources and technical references
- IEC 62444:2010, Cable glands for electrical installations, accessed 2026-09-11.
- ASTM E1012-19, Standard Practice for Verification of Testing Frame and Specimen Alignment Under Tensile and Compressive Axial Force Application, accessed 2026-09-24.
- ASTM E4-24, Standard Practices for Force Calibration and Verification of Testing Machines, accessed 2026-09-11.
- NIST, Calibration of Force Transducers, accessed 2026-09-11.
- ASTM E2309/E2309M-20, Standard Practices for Verification of Displacement Measuring Systems and Devices Used in Material Testing Machines, accessed 2026-09-11.
- IEC 60529, Degrees of protection provided by enclosures, accessed 2026-09-11.
- OSHA 29 CFR 1910.305, Wiring methods, components, and equipment for general use, accessed 2026-09-11.