Applies to waterproof heating cables having a rated voltage greater than 50 V but not exceeding 450/750 V a.c. with positive temperature co-efficient resistive elements for a majority of industrial applications such as pipe tracing and heating of vessels and associated equipment. It applies only to the heated part of the cable and not to any complete unit including cold tails and terminations. Non-waterproof heating cables are not considered. This publication has the status of a Technical Report - type 2