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Originally Posted by Delphinus
+1. It's too bad GFCI breakers are so expensive. But the logical workaround is to use the bathroom plugins because any downstream plug is also GFCI'd then in a way.
One thing has always confused me though. I hear 50% "this" and 50% "that", where one camp says a GFCI senses an imbalance between the hot and neutral wires, and the other camp says a GFCI senses any kind of current on the ground wire. Is it a case of "both are true" or is it a case of "the other one is an arc fault" (and if not, what is an "arc fault")? The reason I'm not convinced is because I once touched an otherwise all-powered-down light reflector (which was grounded), there was a static zap, and the GFCI tripped. (Nothing else was on at the time). So the static spark must have travelled to ground? That suggests GFCIs or at least THAT particular GFCI I was using at the time would trip on "current on ground" ?
One thing about GFCI's is I get these random trips, at the rate of say once per year or so. I'm not really sure what's up with that. That's an exceedingly difficult thing to troubleshoot and diagnose because I'll go through the checklist (unplug everything, add it back one by one, using a multimeter to see if there's any current to ground) and seemingly nothing will be the chronic misbehaver. I don't know if this means the GFCI is just dodgy, or it's some kind of very infrequent fault that comes and goes, or if my checkout procedure itself is "faulty" (pun quasi-intended  ) |
The camp that says "too ground" is correct as well to a certain extent, any current going to ground... Is NOT going to ID. A common work around for old houses where receptacles don't have grounds is to put all those circuits on GFCI. In fact, its required by code when doing a reno or any other changes to the wiring in those cases.
You certainly can get nuisance tripping on GFCIs. Ceiling fans for example, on startup it will draw more current then when running. For a brief moment that inrush current will oppose a change in current between hot and ID if its a large enough difference and for a long enough period, GFCI trips.
Arc fault is entirely different, its name is self explanatory, senses an arc, code says they have to be used in bedrooms... You push your bed or mattress up against the wall, bend the plug down causing an arc... That breaker will trip, without it, you potentially have a fire.
The logical choice is to NOT use the a plug on the LOAD side of the bathroom receptacles, what happens when you plug your 1200watt hair dryer in? You will overload that circuit with pretty much anything else running on that same circuit... And trip the breaker... Making nuisance tripping even worse.