There are a variety of technologies and methods used to test the insulation of wire and cable, including high-potting, very low frequency (VLF), power factor, partial discharge, time-domain reflectometry (TDR), and "thumping.”
It is hard to believe, but 2010 is almost over and with it, my term as IAEI International President is drawing to a close.
Article 90 is rarely given consideration when someone references the National Electrical Code (NEC).
Ground-fault protection of electrical equipment is required by the National Electrical Code (NEC) in order to minimize the damage to the equipment in the case of a ground fault.