ECN Forum Forums General Topics of the Trade General Discussion Area Changing a light bulb trips OTHER circuits?

Nope, no GFCIs, just normal breakers. One of the electricians here had a new theory that sounds pretty likely- he thinks the bulb grounded out; that it was getting high voltage on one side through the ballast, and the other prong shorted out to ground against the side of the fixture. This would have put a fairly high voltage and current on the ground.