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Saturday, January 15, 2011

GFCI Protection

The rules regarding GFCI seem to be misunderstood, alot. Everyone knows they are required in bathrooms, outside and in garages, but I see this question quite frequently: What are the rules for replacing 2-wire receptacles without replacing the wiring? The answer is you can replace them with new 2-wire receptacles or GFCI receptacles. You can feed receptacles downstream of the first GFCI receptacle with standard 3-wire receptacles as long as they are labeled "GFCI Protected - No Equipment Ground". These stickers come in the box with the GFCI receptacles. Even the 15A GFCI receptacle has a 20A feedthrough, therefore it does not restrict the circuit amps.
Another misconception is the use of GFCI breakers vs GFCI receptacles. They work in exactly the same way. The determining factor is usually ease of resetting the GFCI or routing of wiring. If the receptacle is in an elevator pit in a commercial building, it is easier to reset if you use the receptacle, but in a residential dwelling it is just as easy to put the bathroom receptacles, garage receptacle and exterior receptacles on a breaker.
Another rule that is often broken is the use of GFCI protection during construction. The building is getting near completion, the power systems are on, the receptacles and lighting have been turned on, but there is still work going on. People start plugging their cords into the receptacles in the walls. Why not they are hot and much closer than the temporary receptacles mounted at the temp panel, which may have already been removed anyway. The code requires that construction personnel use GFCI protection during all construction. Workers need cords with built in GFCI or the GFCI plug in units. This requirement is for all workers, not just the electricians and not just on commercial or industrial projects. This also holds true for remodel work in  an existing facility.
Another misconception is that GFCI receptacles require a ground connection. This is 100% false. A GFCI monitors current flow on the "hot" wire and the "neutral" wire. If there is more than 5 miiliamps difference between them, the GFCI interrupts the circuit. So basically, what goes out on the hot must come back on the neutral. If it goes anywhere else, the circuit is opened.

1 comment:

  1. Very informative information to one’s who is new in industry or to those who are frustrated from exothermic welding system & exothermic welding kits . It is a process to get the strong joint for conductors with some suitable simple steps.