An Accelerated Screening Test for Polyethylene High-Voltage Insulation

Polyethylenes are rated for relative a-c dielectric strength by their treeing tendency at a "standard defect," i. e., a needle point embedded in a block of polyethylene and stressed versus a remote ground. The "1-hour characteristic voltage," defined as that causing half a group of samples to develop trees in one hour, has been raised by additives from 19 kv (kilovolts) (original) to as high as 80 kv. Results correlate with a-c step and life tests on wire.