These are single core cables with cross-linked polyethylene insulation and an outer sheath, giving a 90 °C conductor rating in place of the 70 °C of PVC. 6181XY to BS 7889 is a 600/1000 V cable sheathed in black PVC, used for submains and heavy single core runs on tray or in free air. 6181B to BS 7211 is a 300/500 V cable with a low smoke, zero halogen sheath, used where a building's fire specification rules out PVC.
Key applications
- Submains and riser conductors run on tray or ladder (6181XY)
- Single core connections to switchgear, transformers and busbar systems (6181XY)
- Large-section runs in free air or clipped direct where mechanical risk is low
- LSOH general wiring and equipment connections in public buildings (6181B)
- Installations where a 90 °C insulation rating is needed to achieve the required current
Features and benefits
- XLPE insulation gives a 90 °C rating, so more current for the same copper
- Cross-linked insulation resists deformation at temperature better than PVC
- 6181XY is rated 600/1000 V, suiting submain and switchgear work
- 6181B offers the same thermal benefit with low smoke, halogen-free performance
- Sheathed construction allows runs outside conduit and trunking
Specification notes and limitations
The two designations are not interchangeable: 6181XY is a 600/1000 V cable and 6181B is 300/500 V, so 6181B must not be used as a substitute on a submain designed around the higher rating. The 90 °C rating is only realisable if the glands, terminals and accessories at each end are also rated for 90 °C, which many are not — in practice the circuit is often designed to 70 °C at the equipment. Neither cable is armoured, so neither is suitable for direct burial or for locations with a real risk of impact. Where several single cores form one a.c. circuit they must be arranged and cleated correctly, kept together through any metal gland plate, and secured against the forces generated under fault conditions.
