Specifying Steel Wire Armoured (SWA) Terminations

Ensuring you order the correct brass gland kits and fixing cleats for XLPE/SWA/PVC cables is vital to avoid delays on industrial sites. Gland sizing is dictated by the overall diameter of the cable bedding and the outer sheath, which fluctuates depending on the manufacturer and the cross-sectional area (mm²) of the copper conductors.

Understanding Gland Suffixes (The 'S')

A common error during material ordering is confusing standard glands with 'Small' variants, such as a 20 versus a 20S.

• Both a 20 and a 20S gland have the exact same M20 outer thread diameter for fixing into the enclosure knockout.
• The 'S' (Small) denotes that the internal diameter of the gland body is reduced to grip the outer sheath of a thinner cable. Putting a 1.5 mm² 3-core cable into a standard 20 gland will result in a loose fit, compromising the IP rating and mechanical grip.

BW vs. CW Gland Types

• BW Glands: Designed for dry, indoor environments. They terminate the steel wire armour to provide mechanical retention and earth continuity, but do not provide a watertight seal around the outer sheath of the cable.
• CW Glands: Designed for external or wet environments. They incorporate an environmental seal (usually an internal compression olive or rubber bush) that grips the outer PVC sheath, achieving an IP66 rating to prevent water ingress into the switchgear.

Earthing the Armour

The steel wire armour must always be reliably connected to the Main Earthing Terminal (MET) to comply with BS 7671 fault protection requirements. When terminating into non-metallic enclosures (like plastic adaptable boxes), a 'Banjo' earth tag or an 'Earth Nut' must be utilised to bolt a dedicated fly-lead from the brass gland directly to the circuit protective conductor (CPC).