gfci
I would like to replace a regular plug with a GFCI plug. The current plug has:
The breaker is "double" (see picture)
To the best of my knowledge, there is no switch linked to half of the outlet.
Thank you!
The first problem is that you may be using the wrong cable and breakers. NEC calls for 2 20Amp small appliance circuits in the kitchen, to accomplish this you'll need to switch to 20Amp breakers and #12 wire.
The next problem. You'll have to pull new wire anyway, if you want to hook up GFCI receptacles. GFCI receptacles will not work properly with a shared neutral, you'll end up with nuisance tripping with a shared neutral. GFCI receptacles work by monitoring the balance between hot and neutral, so if the neutral is shared the GFCI will not work properly.
To wire up the kitchen properly, you'll have to pull 2 new 12/2 cables from the breaker to the kitchen (all #14 wire on that circuit will have to be replaced). Then install 2 20Amp breakers, to supply the kitchen. You'll install the GFCI's as the first receptacle on each circuit, which will protect all downstream receptacles.
You can share a neutral between 2 GFCI receptacles. The catch is you'll have to pigtail the neutral to the receptacles, not use the neutral from the load side of the first GFCI to feed the second.
So you should be able to do something like this...
But not like this...
You'll then be able to use the load side of each receptacle to feed other devices, like this.
GFCI devices work by comparing the current incoming on the hot wire to the current leaving on the neutral wire. If there's a difference, it means electricity is leaving the circuit somehow (a "ground fault") and the GFCI cuts power*. The GFCI doesn't do anything with the ground conductor—in fact, you don't even need to have one at all. One way of upgrading a 2-prong outlet (without ground) to a 3-prong outlet is by inserting a GFCI device upstream or using a GFCI outlet.
So I'm guessing there is a small amount of current in your scenario, and when you touch the white and ground together, some of that current goes into the ground and doesn't return through the GFCI neutral. Do any of you lights have timers, nightlight, etc.?
(BTW I'm not sure it matters for this question but your description of how the wires up is a little confusing to me. LINE and LOAD are opposite sides of the GFCI device, but you use them interchangeably. If you want a downstream device to be protected by the GFCI it must be connected to the LOAD side. Anything on the LINE side is considered upstream and is unaffected by the GFCI.)
Best Answer
Multi Wire Branch Circuit
You have an MWBC. It provides 2x the power with 1.5x the wires (3 wires instead of 4). The catch is:
Your old setup has all of that. What it doesn't have is GFCI protection. While with an ordinary single circuit, you can install GFCI at the point of use (a combination GFCI/receptacle) or in the panel, with an MWBC the usual solution is in the panel. You do actually have an alternative, but it is more work and only makes sense if you also want to have more receptacles:
That will essentially split the MWBC into two separate circuits, each of which can handle a full 15A load. If you want to use two large tools in one place and nothing else, then the existing receptacles (plus GFCI in the panel for safety) makes sense. But having 4 receptacles (2 on each of 2 circuits) can be very useful.