GFCI receptical with three wires
Diomedes
| Posted in Energy, Heating & Insulation on
I have finally finished my kitchen renovation (Thank the gods) and I am just putzing around with the finishing touches. I am installing my GFCI recepticals and I am stumped. My electrician ran 12/3 wire from a double pole breaker in the panel (The red wire is in one pole and the black is in the other) to all the outlets, I have no Idea how to install the receptacles. Murphy’s law being what it is, my electrician is on vacation. Can anyone help? What the hell do I do with the red wire?
Replies
Does it continue as 12-3 from each box to the next one then you need to either install a GFCI as each location or replace the breaker with a 2 pole GFCI breaker and use regular receptacles.
To install GFCI at each location; You need to connect the incoming and outgoing neutral to a white pigtail. Then connect the pigtail to the LINE neutral on the GFCI.
For the hot select one leg and you can either pigtail it and connect GFCI hot or using the back wire holes connect the income and outgoing hot leg.
For the other hot leg just wire nut the income to the outgoing.
The other thing is that you need to pick which leg (red or black) each receptacle will be on. Depending on what kind of appliance and where they are commonly either every other receptacle is on one leg or all of the receptacles on the left or on one leg and the right on the other.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Thanks for the reply, there is a 12/ 3 wire running to each box, and I do plan on putting a GFCI at each point. However is there any way you could talk to me like I'm four...I'm not quite sure what you mean by 'a leg'. Do you mean either the red or black?
Many thanks and excuse my ignorance.
Diomedes,Hartmann means the red and black conductors when he speaks of "legs." The red connects to one side of the double pole breaker, the black to the other. They are out of phase with each other, which allows you to use a common neutral (white wire).Your electrician ran two circuits in one cable for convenience. What is great about this is that you retain the option down the road to move outlets to the other circuit if your loading should change due to new appliances, etc.Reread his post carefully, for it contains all the information you need to install your GFCI's.Bill
(edited for typo)
Edited 6/18/2007 2:36 pm by BillBrennen
Wow thanks for all the input guys! I'd love for my sparkie to come and finish but when I said vacation I mean vacation: He's off for a month. Me I'm getting married in July and the future missus is gonna kill me if the house isn't ready.
I have read the post to a tee and am planning to try it out and see how it goes (don't worry the circuit will be off and 911 will be on standby). I'm just curious though, if I pigtail the incoming and outgoing and tie them into the "line" on the GFCI, will this affect the plugs downstream, since they have their own designated contacts on the receptacle. Or am I just being paranoid?
Once again guys thanks for all the help, you have no idea how much I appreciate it.
No, the GFI's won't affect downstream units so long as you tie only to the "LINE" terminals. The function of affecting downstream units is limited to the "LOAD" terminals.Bill
I've seen the 3 wire used this way frequently, especially in kitchens, where often the outlets are split - the top half are on one circuit and the bottoms are on another. But how to toss GFCI into the mix, well, let's just say that I haven't even stayed in a Holiday Inn lately, so I'm no help at all. I have a healthy respect for the limitations of my knowledge.
The OP's situation is just like what you have seen - the rough wiring is identical. The only difference is that because you can't split a GFI like a regular duplex receptacle, instead you alternate them, or do all left/all right, as Mr Hartmann mentioned.Bill
You can't use the first GFCI to protect other outlets because of the shared neutral. Each location will need it's own GFCI UNLESS you only install outlets on one leg of the circuit, which would defeat the whole purpose of the 2-leg circuit.
What you have is called a multiwire circuit. US residential power is a uses a 240 transformer with a center tap. From the center tap to either hot is 120 volts. From one hot to the other is 240 volts. But in an application like this there are no connections between the two hots so it is two 120 volt circuits.When we talk about a leg we are talking about of of the hots (or the hot to neutral).In this example the legs are indicated by the black and red colors.Here is a drawing showing individual GFCI on a multiwire circuit.http://www.selfhelpforums.com/attachment.php?attachmentid=214&d=1099537222If that does not show go tohttp://www.selfhelpforums.com/showthread.php?t=2248Look at #6 and the attachment..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I followed your instructions to a tee and ....success! Mind you I only did one. I have three outlets around the kitchen counter each one has a three wire run to it. The first has two 12/3 wires. I joined the reds and pigtailed the whites and blacks and ran them to the line section of the GFCI. Now my question to you is on the second GFCI (where the outlet has one 12/3 wire in it) should I power it with the black and cap the red? If so why did the electrician run three wire? What benefit is it?
Thanks again for all your help and input.
Three-wire installations can be used to even out a load configuration. In multiple outlet situations, like the small appliance circuits required in kitchens, outlets are often "wired every other one". Eg, if you have breakers A and B, you wire your outlets A - B - A - B, so when you are working in an area, you can plug into two outlets so you don't overload one breaker. The problem your electrician has introduced is that these work best with 4 wires (two neutrals, not one as in your situation). Also, installing a double pole breaker makes this a 220 circuit instead of two 110s. So, as Bill Hartman said, you need to swap out that two pole breaker for two 20A single pole breakers.
Because you have a shared neutral, you shouldn't use the "load" terminals on your GFCIs. (Leave them covered with the tape that they come with.) You need to wire each one to the feed lines, and not connect anything to the load terminals.
In the first box, join all the feed wires, red to red, black to black and white to white, and ground to ground. If you have metal boxes, pigtail a ground wire to the box. Then take pigtails off the blacks and whites and connect the pigtails to the GFCI. Wire nut all your connections. Do the same in each box in the run, switching between taking the pigtails off the black/white and red/white in alternating boxes. Each box will have one hot wire, red or black, that's only wired through the box, and not attached to anything else.
Harder to say than to do! The only problem you may have is that with that extra wire in the box and a bulky GFCI, it may be a bit cramped. (I hope your electrician used deep boxes!) Be careful not to muck up the insulation on any of the wires when you are jamming them in.
Mike HennessyPittsburgh, PA
Will I be O.K with the double pole breaker in the box? It appears that the breaker is only wired up to two outlets. The third receptacle in the kitchen is on another dople pole breaker and is shared with a plug upstairs in the bathroom.
"Will I be O.K with the double pole breaker in the box?"
Bill Hartman just answered that Q -- beat me to it. Personally, I'd prefer two. Pro is it makes it easier to figure out what the problem is if it blows. Con is you can turn off one breaker, think the circuit is dead and get a surprise when you open a box and the neutral and second hot leg still have voltage. (Just another reason to use 4 wires instead of 3.)
"It appears that the breaker is only wired up to two outlets. The third receptacle in the kitchen is on another dople pole breaker and is shared with a plug upstairs in the bathroom."
If the other outlet in the kitchen is on a small appliance circuit (e.g., over a counter), it cannot be on the same circuit with the bath outlet -- the SAC breaker has to be dedicated. If I'm not mistaken, the bath outlet should be on a dedicated circuit as well. BH will probably chime in on these items & he's way more versed on the code than I am so, what he says.
Mike HennessyPittsburgh, PA
"If the other outlet in the kitchen is on a small appliance circuit (e.g., over a counter), it cannot be on the same circuit with the bath outlet -- the SAC breaker has to be dedicated. If I'm not mistaken, the bath outlet should be on a dedicated circuit as well. BH will probably chime in on these items & he's way more versed on the code than I am so, what he says."That is one that you need to turn the code book upside and heat it to reveal the invisalable writing. Then go to the code forums and watch the 5 pages of "discusion" and no conculsion.A mutliwire circuit is treated as one circuit for things like feeding an out building. But once there you can split it and and have two separate 120 circuits.In terms of fuctionality each location (kitchen, and bathroom) have a full 20 amp supply, which is what the code is asking for..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I thought you are required to use a double-pole (handles tied together) breaker if you run the two circuits on one (3 conductor) wire. This to fully protect when you work on the circuit.
the handle tie is required when BOTH hots . red and black .....are terminated on one duplex receptacle ....
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., wer ist jetzt der Idiot ?
Thanks- is it OK to have the handle tie when that is NOT the case?
I wouldn't have a problem with it , it is your house !but it could make troubleshooting a real PITA later
so don't start throwing handle ties on everything.. :)and, make sure the panel schedule is legibly marked for those circuits.
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., wer ist jetzt der Idiot ?
"I followed your instructions to a tee and ."Not exactly.I said that to distribute the GFCI's on the two legs (ie, the red and black). Either A-A-A..B-B-B.. Or A-B-A-B-A-B-... Depends on where you are goig to put large appliances. Those are Typically toastera (and anything else with a heating element) and counter top microwave.Also this DOES NOT NEED to have a 2 pole breaker as there is no 240 on any device (receptacle). But you can use one.But there is a big arguement about this and mutliwire circuits in general.The pro for using a 2 pole breaker is that if you turn it off you won't be "surprised" if you open the other leg or open the neutral while there is a load on the other leg.The con is that if you have an overload on one circuit that it trips both of them..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Edited 6/19/2007 1:24 pm by BillHartmann
Sorry...and thank you for explaining all this.
"I said that to distribute the GFCI's on the two legs (ie, the red and black). "
The one GFCI that I have installed has the two blacks joined and pigtailed running to the LINE and the two whites joined and pigtailed running to the other side of the LINE. The two reds are joined and simply capped. So if I have done this correctly...the next receptacle should draw the current from the red(s) and the blacks should be capped and left alone???
A friend of mine (a shoemaker who pretends to be GC...where as I am a lowly grade school teacher who just pretends to be a GC) told me that I should run the black to the line and the red to the load and sever the connection line between the two (where that is heaven only knows, cause I can't see the damn thing!). Then run the neutral only to the Line and that should power the top and bottom receptacle on a seperate circuit. So if the top goes, the bottom will still work.
My head hurts...Christ the wife is going to have to wait till the damn electrician comes back from holiday!
Edited 6/19/2007 5:50 pm ET by Diomedes
Diomedes,Your friend is confusing regular duplex receptacles with GFI receptacles. They are different animals inside. Do NOT wire the GFI's as you quote him saying. Doing so will cause much light for an instant, followed by smoke, darkness, and muttered curses about your friend's parentage.Leave the tape on the "load" terminals; attach nothing at all to them. Just do as you stated in your second paragraph, which is what Bill Hartmann described to you back at the start of the thread. Or wait for the electrician.Bill
" The one GFCI that I have installed has the two blacks joined and pigtailed running to the LINE and the two whites joined and pigtailed running to the other side of the LINE. The two reds are joined and simply capped. So if I have done this correctly...the next receptacle should draw the current from the red(s) and the blacks should be capped and left alone???"Exacta munga "A friend of mine (a shoemaker who pretends to be GC...where as I am a lowly grade school teacher who just pretends to be a GC) told me that I should run the black to the line and the red to the load and sever the connection line between the two (where that is heaven only knows, cause I can't see the damn thing!). Then run the neutral only to the Line and that should power the top and bottom receptacle on a seperate circuit. So if the top goes, the bottom will still work."I hope that he does a better job of shoemaking than playing electrican.You can't do that with GFCI's. GFCI receptacles are a ground fault interrupter that on the load side feed a duplex receptacle (and also the load terminals). With a plain duplex receptacle you can break the link between the two hot terminal screws so that you can feed them from different hot legs. More commonly that feature is used where you want a receptacle controled by a wall switch, but the other half always hot.There is no advantage to spliting the receptacles on 2 different legs in a kitchen unless you have have a specific location where you have two big appliacne that you will be using at once. And in that case it is easier to install a 2 gang box and use two different receptacles.And if you do that you need to use a 2 pole GFCI breaker to get your GFCI protection..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
To all the lads who have helped me out of this pickle; When you die may they bury you in a casket made of a 100 year old oak tree, which I intend to plant tomorrow!
Cheers, many thanks to Mr.Brennan and Mr. Hartmann.
Now to pester some people about installing some hardwood flooring....
Bill
Great link I thought I'd make it a little easier to look at hope this uploadszeeya
Bill - It sounds like he wanted to get 2 circuits from one wire with a shared neutral, or am I missing something? (quite possible)
Would the OP be better off letting his sparkie finish? buic
If s double pole breaker - I am no electrican but it would appear that for some reason the system is set up for 240V. It may be that the electrican was providing wiring for two 120V circuits with the red the hot leg on one and the black the hot leg on the other. I have seen here on the board how one can wire two circuits this way but way beyond my experience.
Seriously, I wouldn't do anything without a real electrician looking at this. I am not one, but,
I can think of a few variations of your description, and only one of them is okay to hook up the outlet.
Can it wait a week? Or get someone else to take a look?...buic