The PGT-0400 is a ground-fault-relay test unit designed to test current pickup level, time-delay and coordination of ground-fault protection. The tester injects current through the window of installed ...

The PGR-8800 is a microprocessor-based protection relay that limits arc-flash damage by using light sensors to rapidly detect the arc and then trip a circuit breaker. Phase current-transformer inputs ...

Not long after I began contributing to Hagerty eight years ago, I wrote a detailed four-part piece on electrical relays and how they work in cars. You can still find the articles here (Part I: Why We ...