Rated voltage U0 / U 500V (450/750V) and under control, monitor and protect the loop line cable. PVC Armoured ... controlling return circuit, protecting and measuring in power distribution unit under the circumstance that the rated voltage is up to 450 ... .5 7-61 Permanent installation indoors, incable ditches, pipes or under ground. Be able to bear stronger outer mechanical force 4, 6 ...