This is the same BS 5467 armoured construction in the larger conductor sizes used for main distribution: XLPE insulated stranded copper cores, PVC bedding, galvanised steel wire armour and a black PVC sheath, rated 600/1000 V and 90 °C. The conductors are stranded and, in the bigger sizes, shaped to keep the overall diameter down, and the armour wires are correspondingly heavier.
Key applications
- Main incoming supplies and transformer to switchboard connections
- Submains between distribution boards on industrial and commercial sites
- Buried site distribution between buildings and external substations
- Supplies to large motors, chillers, compressors and process plant
- Runs on cable ladder, tray and trefoil cleats
Features and benefits
- Covers the current range above what the small multicore sizes can carry
- Shaped stranded conductors keep the overall diameter and bending radius manageable
- Heavier armour wires give substantial mechanical protection and a low-impedance earth path
- 90 °C XLPE rating with a 250 °C short-circuit limit
- Suitable for direct burial with appropriate bedding and depth
Specification notes and limitations
At these sizes the armour's adequacy as a protective conductor needs checking against the prospective fault current, and on the largest sizes a separate CPC is often required. Weight and bending radius are the practical constraints: these cables need proper cable rollers, drum handling and cleats sized for short-circuit forces, and an over-tight bend will distort the armour and the insulation. Terminations must use glands matched to the armour diameter, with the armour positively earthed. As with all XLPE cable, the 90 °C rating cannot be used unless the terminating equipment is rated for it. Buried installations require correct depth, bedding, warning tape and derating for soil thermal resistivity and grouping.
