Cable Gland Selection: Cable Fit, Sealing, Armour and Earthing

What cable data does a gland selection need?

Start with the manufacturer's current cable data rather than the conductor size on its own. Two cables with the same core count and conductor area can have different outside diameters, so the gland must be chosen for the finished cable. Collect these details:

• Minimum and maximum overall diameter
• Inner-sheath or bedding diameter where a seal bears on that layer
• Armour type and dimensions
• Outer-sheath material
• Screen or metallic-sheath details
• Mass, temperature range and expected mechanical load

IEC 62444 (EN 62444) sets requirements and tests for the construction and performance of complete cable glands, so ask the supplier which edition the gland is declared against. Project requirements may add enclosure, environmental, electrical or explosive-atmosphere obligations on top of that.

How do you check the sealing range and seal materials?

The delivered cable diameter must fall within the gland manufacturer's declared sealing range. Do not choose a size at the extreme edge of that range. Leave practical allowance for cable tolerance, ovality and installation conditions. Confirm which sealing arrangement the design uses: outer-sheath sealing, separate inner- and outer-sheath seals, a multi-hole insert, or a barrier compound.

Do not remove sheath layers or add tape merely to make an incompatible gland fit. Such field changes can defeat sealing, retention and certification. The sealing element and the cable sheath must remain compatible with oil, chemicals, cleaning agents and long-term heat. For the sheath material options, see cable insulation and sheath material selection.

Does armoured cable need a matching gland and earth path?

A non-armoured gland normally provides sealing and retention appropriate to its declared design. For armoured cable, the gland must also match the actual metallic layer, whether that is steel wire, steel tape, aluminium wire or braid, and its dimensions. Confirm the armour clamping range, the continuity requirement and any fault duty assigned to the armour or bonding path.

Multicore cables commonly use steel wire armour (SWA). Single-core AC cables normally use non-magnetic armour, typically aluminium wire armour (AWA), because steel armour around a single AC conductor causes magnetic losses and heating. BS 5467 covers single-core AWA and multicore SWA cables rated 0.6/1 kV, and BS 6724 covers the LSZH-sheathed armoured equivalent. For more on this choice, see when to choose armoured cable.

Do not assume that every metallic gland provides an adequate protective-earth connection. Review the gland's declared electrical function, the cable construction, the enclosure interface and the project earthing design.

What must match at the enclosure entry?

Confirm the thread form, size, pitch and usable length. Also confirm whether the enclosure has a threaded entry or a clearance hole, the wall thickness and material, and which accessories are required: locknut, earth tag, serrated washer, sealing washer, adaptor or reducer. A correct cable-side seal cannot compensate for an incorrect enclosure entry.

Confirm each row against the manufacturer's current documents for the exact gland model.

Ingress protection is an assembly result. It depends on the gland, seal, enclosure surface, entry geometry, accessories, installation torque and cable diameter. Under IEC 60529, IP66 means dust-tight with protection against powerful water jets, and IP68 means continuous immersion under conditions stated by the manufacturer. Outdoor and washdown duty may also require drainage, suitable orientation, UV resistance and corrosion control.

Body materials such as brass, nickel-plated brass, stainless steel, aluminium and non-metallic products differ in corrosion resistance, mass, bonding and compatibility. Avoid unacceptable galvanic combinations between the gland, its accessories and the enclosure.

How do temperature and installation conditions affect the choice?

Check the lowest and highest service temperatures for the body, seals, accessories and any barrier compound. Include the ambient conditions, enclosure heat, solar exposure and the cable's own operating temperature, because each can raise or lower the temperature at the entry.

The installation work instruction should cover cable preparation, armour cut-back, clamp assembly, seal orientation, any permitted lubricant, installation torque, bend clearance, locknut and bonding accessories, and inspection for sheath damage. Follow the instructions for the exact model. Excessive tightening can damage the cable or seal, while insufficient tightening can reduce retention and ingress protection. On receipt, check the following:

1. Match the gland model and size to the approved schedule
2. Check certificates and any special conditions where applicable
3. Verify the cable, seal and armour ranges against current documentation
4. Confirm the thread and all accessories
5. Inspect seals, threads and the cable sheath for damage
6. Follow the preparation and torque instructions
7. Check armour engagement, bonding and the finished entry

What changes when the gland is used in a hazardous area?

General industrial suitability does not establish suitability for an explosive atmosphere. IEC 60079-14 addresses the design, selection, installation and initial inspection of electrical installations in or associated with explosive atmospheres, and hazardous-area glands additionally follow the IEC 60079 series. The design must account for the protection concept, the gas or dust group, the temperature class, the zone and the certificate conditions.

Before ordering, verify the current certificate and marking, the permitted cable construction and diameter, the sealing method, the thread interface, the temperature range and any specific conditions of use. Do not substitute a visually similar gland. Gland selection is part of the complete cable, enclosure, earthing and environmental design. Hazardous-area and life-safety installations require competent engineering and compliance with the governing standards and certificate conditions.

Frequently asked questions