The development and testing of a track resistant sheathing material for aerial optical fibre cables

A sheathing compound has been developed, which has an optimum level of ATH, UV stabiliser and crosslink density and can be easily processed as a sheathing material for aerial optic fibre cable. It has been shown to possess very good resistance to tracking at 25 kV 50 Hz and its mechanical properties change very little after being subjected to 2000 hours of UV radiation according to the ASTM Specification G53-84. A tensile test on a 50 metre length of cable, made from this compound and held by standard liners and dead-end grips as used for installation, has been carried out up to a load of 2.2 times the maximum working load. At this level, there was no damage to the sheath or any other component of the cable. A 132 kV trial installation, the first totally non-metallic self-supporting cable in the UK has been strung along a power line with one circuit live.<>