Installation Problems and Testing of Cable--5 to 35 kV

Wire and cable, the most ubiquitous of all electrical components, are susceptible to failure from many causes unrelated to service life. Installation damage ranks high in the list of failure causes: the interrelationship between the eight major installation methods and the ways in which they are most likely to cause damage are explained. Damage is largely due to oversharp bending, excessive lateral (sidewall) pressure, puncture, and abrasion. This damage may be avoided by readily usable variations in the installation process, which are outlined in the paper. To detect approaching failure of cable insulation due to damage, defects, or simple electrical degradation, testing with high potential dc at logical intervals has been found highly effective. In-service failures are thus substantially avoided. The reasoning behind testing methods, details on testing procedures, evaluation of results, and testing history are explained.