GFCI

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Moderator Post (s) for this thread: > Combo Switch how-to by doug seibert on 08/28/2005

I disagree with the posts saying grounded receptacles are safer than GFI's. This is a common misconception. Fuses and circuit breakers protect wires not people. GFCIs faule when un unballance of current exists between the hot (Non grounded) conductor port and the "Neutral" (Grounded) conductor port on the receptacle or any downsteam protected loads is detected. The trip time is designed to be 2 Mili or micro seconds (I forget which)or less thereby preventing any current that can cause death to people. Virtually no current into a grounded human circuit can flow. A circuit breaker, say a 15 Amp breaker, will allow at least 15 amps (though in practice it's more like 22 Amps) to flow for much longer than is required to stop a human, or feline, or cannine life. If you are unlucky enough to have FPE Breakers on that old 2 wire system, well, you'll be a crispy critter before that thing trips. I have measured 41 Amps on a 15 Amp FPE that held. I concede that GFIs are prone to failure, but I tell all my customers to exercise them by tripping and resetting them at least quarterly, if not monthly, by hitting the test button then resteeting to prevent mechanical failure. It is certainly safer to have both a grounded 3 wire system and GFIs, but GFIs alone are safe for living things. and Isidro, you can put up to 7 receptacles on the load side of a GFI, put in 3 prong receptacles down stream, and you will be safe and NEC compliant.