AS NZS 1747:2022 – Reeling, trailing and feeder cables used for mining – Repair, testing and fitting of accessories
AS NZS 1747:2022 – Reeling, trailing and feeder cables used for mining – Repair, testing and fitting of accessories.
3.11 Joining of PILSWA and XPLE armoured cables
The following requirements are for splicing and transition splicing of PILSWA and XLPE armoured cables:
Environmental conditions shall be taken into account when selecting a splicing kit.
Splicing kits shall only be used on cables specified in the kit manufacturer’s installation instructions.
(c) Joining kits shall be fitted in accordance with the kit manufacturer’s installation instructions.
3.12 Replacement of insulation or covering over conductors
During all procedures involving the replacement of insulation or covering, including any semiconductive layers over conductors, insulation or covering, absolute cleanliness of the repair and repair materials shall be maintained at all times. This may entail the use of suitable solvents (see Clause 3.2). Ensure components of the cable are not damaged which do not need repair or which may have already been repaired.
The interior of the cable in the area to be repaired shall be inspected for the presence of moisture which could adversely affect the repair. Where moisture is present, it shall be removed.
All repair materials shall conform to the appropriate requirements of Appendix F.
Where the insulation or covering of conductors is being replaced, the procedure shall be as follows:
(a) All damaged insulation or covering shall be removed.
The clean ends of the insulation or covering shall be chamfered so that the ratio of the length of taper to the radial thickness of insulation is approximately 8:1 but need not be greater than 6 0mm.
For cables rated 3.3 kV and above, the semiconductive textile tape conductor screen shall extend approximately 10 mm beyond the chamfer of the insulation. Cables incorporating a semiconductive insulation screen shall have the insulation screen removed approximately 10 mm beyond the insulation chamfer. The end of the insulation screen shall be chamfered for all cables 6.6kV and above.
With all Class 1 cables and 22 kV Class 2 cables, the bond between the insulation and insulation screen shall not be broken.
Once the chamfers are completed they shall not be handled or contaminated in any way.
NOTE Self-amalgamating insulation tape that does not require curing by vulcanisation need not be pre-cooked before the sheath is vulcanised.
Where a separator tape over the conductor is considered necessary by the repairer, one layer of suitable tape shall be applied tightly over the conductor. The tape shall not encroach onto the insulation taper. For cables 3.3 kV and above, such tape shall be semiconductive.
(d) On cables having a voltage rating of 3.3 kV and above, a semiconductive repair tape of an appropriate type, compatible with the original cable, shall be applied concentrically and tightly over the conductor with a slight overlap of the original conductor screen ends.
The thickness of the semiconductive layer shall be approximately equal to the original conductor screen thickness.
The semiconductive layer shall not encroach onto the insulation taper.
An appropriate insulation repair tape shall be applied tightly over the conductor or over the repaired conductor screen or separator tape as appropriate, to provide a circular cross-section.
The tape shall progress layer-by-layer up the chamfer until the radial thickness of the repair material applied results in an overall diameter at least 5 percent larger than the original core insulation diameter. The final layers of repair tape will therefore finish past the ends of the taper and be over the outer surface of the core insulation.
For all extruded semiconductive cables, where a separator tape over the conductor insulation is considered necessary by the repairer, one layer of suitable tape shall be applied tightly over the insulation. A semiconductive repair tape of appropriate type, compatible with original cable, shall be applied concentrically and tightly over the insulation repair material, to a thickness approximately equal to the thickness of the original screen, and overlap both original screen ends to a distance which is at least equal to the diameter of the core.
The layers described in Items (d), (e) and (f) shall be checked that their interfaces are smooth and void free. Any elastomeric conductor and insulation screen shall bond with the insulation.
Where the insulation is likely to be vulcanized at the same time as the sheath or where a metallic screen is to be applied a separator tape shall be applied over the repair.
Individual power conductor insulation and elastomeric insulation screen, if any, shall be cured by vulcanizing, on all cables of voltage rating 3.3 kV and above, before any metallic screen or sheathing materials are applied. Cables with voltage ratings below 3.3 kV may have the power cores vulcanized at the same time as the sheath (and any other components where appropriate) or individually before any sheathing or screening materials are applied.