GFI on one side of a 12/3 2-circuit feed
I want to run two circuits out of a panel on a piece of 12/3. One of those circuits will be a GFI receptacle, the other will be lighting. Will this work, or do I need a dedicated neutral for the GFI?
I want to run two circuits out of a panel on a piece of 12/3. One of those circuits will be a GFI receptacle, the other will be lighting. Will this work, or do I need a dedicated neutral for the GFI?
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Replies
That will work.
Here are you limitations.
You install a GFCI receptacle at each location that you want one. No downstream connections.
Or you split the circuit at the GFCI in two 12/2 circuits.
But it sounds like you only want the one receptacle so no problem.
The neutral on the LINE side does not need to be dedicated.
The neutral on the LOAD side does need to be dedicated.
More detail: this is a bathroom some distance from the panel, so I want to run one line up there rather than two.
There are two receptacles, one at the sink and one for a possible electric heater. I want those on one circuit so that someone can heat the room and run a hair dryer at the same time.
There are a two lighting groups with separate switches (a couple of ceiling fixtures, a couple of sconces). There is a ceiling fan with light over the shower. I thought I would put those on a second circuit. The whole room taken together seems slightly more than one 20A should run, and since this is wide open new construction I decided to go with two.
Based on what you are saying the second receptable for the heater would be a GFI also, not fed as load from the first.
"There are a two lighting groups with separate switches (a couple of ceiling fixtures, a couple of sconces). There is a ceiling fan with light over the shower. I thought I would put those on a second circuit. The whole room taken together seems slightly more than one 20A should run, and since this is wide open new construction I decided to go with two.Based on what you are saying the second receptable for the heater would be a GFI also, not fed as load from the first."First I will answer it as you have written it.It is really a mater of logistics.For example you might run #12/3 to the switch box. There you would have the lights/fans on one hot and the neutral.From the other hot and neutral run 12/2 to the heater GFCI/receptacle and on the same hot run another 12/2 to the vanity GFCI/receptacle.Or run just the one 12/2 to the vanity GFCI/recp and then run 12/2 from the load terminals to the heater recep. This is just an example. There are many variates as where the 12/3 runs and then splits off and which recept has the GFCI.But I would suggest that you split it up differently.The lighting and fan are very minimal loads.But I have not looked at load of curlers and hair driers. Nor do I know what size heater might go in. But both of those large loads.So I would suggest have the heater on a different leg from the vanity recpt. The lights and fans could be on either on of the legs. That scheme would definity require 2 GFCI's.
Since two circuits are coming into one box (befor they split) should the breakers be tied together? Or is good labeling sufficient? Just curious.
TFB (Bill)
I use 2-pole breakers for these setups, to be sure they are on opposite phases. I think if you use individual breakers you have to tie them together.
The code only requires that the breakers be tied (or a 2 pole breaker used) if both hots are on any one device (receptacle, switch, etc).But not if the other the other hot is just spliced in the box.Sorta makes some sense. You can have completely different circuit that is spliced in the box. Not commonly done. but some times it is needed.Worked on a house that my friend bought. The MBR has some horrible flake rock pannel that we got rid of. It was built in the 50's and the number of receptacles and circuits was limited. There where also some illegal spliced and bad wiring.So I ran a new suppy cable to one box and used it to feed the downstream devices that had been on the old circuit.Then ran a 2nd supply cable to that box and used it to feed the receptacle in that box and other boxes in that room. Used a 4 sq box with single gange plaster ring so that I would have enough space.