GFCI from 3 wire source

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  #1  
Old 04-22-15, 07:03 PM
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GFCI from 3 wire source

Hi,

I am trying to update my kitchen receptacles. The current wires are two hot (red and black) and neutral and ground attached to double-pole (15A) non gfci breaker.

How do I hook up the single gfci? I assume I would need to switch back to a single-pole 15A breaker and lose either the red or black? Is there another way like splicing the neutral to be shared and putting in 2 gang gfci's? Is there a gfci that lets me use both red and black hot and 1 neutral as it is currently wired?

Thanks
 
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  #2  
Old 04-22-15, 07:45 PM
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You could cut in a double box and then use two GFI receptacles..... one on each circuit.

However, that is pretty involved as you'd need to cut a double box in. In your situation it might be better to replace the receptacle with a nice new one with the bridging clip removed on the brass/hot side only and then install a two pole GFI breaker.

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Old 04-22-15, 08:29 PM
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The split wired receptacle may be required by the CEC. A two pole GFI breaker would be your only option.
 
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Old 04-22-15, 08:38 PM
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The poster is in Canada. As I understand it Canada requires that each half of a duplex receptacle of a small appliance branch circuit (don't know what they call it) must be on a separate circuit. That is why they can use a 15 ampere CB AND why regular GFCI receptacles are not allowable. The only recourse I see is a 15 amperes, double-pole GFCI circuit breaker.

Hopefully Mr Awesome or another Canadian electrician will respond.
 
  #5  
Old 04-23-15, 07:18 AM
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How many receptacle locations along the counter are involved?

For example if you have three double gang boxes (in three locations) interconnected with one 12/3 cable between any two locations, then you need six GFCI receptacles all with empty load side terminals, not two.

One 3 wire cable cannot carry the load terminal subcircuit from a GFCI receptacle unit along with any other circuit or subcircuit at the same time. The neutral path out of the load terminals of a GFCI may not intersect or lead to the neutral for any light or appliance or device receiving hot from somewhere other than the load terminals of the same GFCI unit.

This makes the (2 gang) GFCI breaker probably the cheapest as well as simplest option.
 
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Old 04-24-15, 11:40 AM
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Your kitchen requires your choice of 15A split receptacles or 20A standard with no more than two receptacles per circuit. GFCI protection is only needed if within 1.5m of a sink.
For the 20A circuit however you would need 12AWG wire, and it sounds like you previously had a 15A split receptacle circuit so likely have 14AWG wire there.
Ideally if you wish to abandon split receptacles you would need to pull in new 12AWG wire for a 20A circuit to satisfy code, but this isn't a new build so I wouldn't say you are obligated to switch all the wiring out. There is nothing dangerous about simply putting in 15A receptacles, you'll just have less power available at each receptacle and will likely trip breakers more often. Personally I would just leave the splits and ensure they are on a 2 pole GFCI breaker.
To simplify what allan said, If you used a shared neutral for GFCI receptacles, you need to leave the load side open or you will get nuisance tripping.
To switch to 15A GFCI receptacles: Use a single pole 15A breaker. Cut the red wire off where it enters the panel, you cannot leave the reds in tact or you will have box fill issues. At your first receptacle box, cut off the reds where they enter. Joint the whites together with a pigtail. Hook your pigtail up to your GFCI receptacle, and the blacks independantly to the receptacle under the same screw. Use a piece of bare wire to bond your receptacle to the screw at the back of the box. Because you are not coming off the load side of the first GFCI, you will need a GFCI for your next receptacle as well.

Your options simplified:
- Change wiring to 12AWG and 20A receptacles
- Leave existing split receptacles on a 2P 15A GFCI breaker
- Follow last paragraph for 15A receptacles on a 1P 15A GFCI breaker
 
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Old 04-24-15, 03:10 PM
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Awesome, does a gfi count more than a duplex towards box fill? Or is it the marette on the neutral that would put you over on box fill?
 
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Old 04-24-15, 03:36 PM
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It has to be the GFI receptacle.

Not to get off on a tangent but what really makes me laugh is the GFI receptacles that are labeled " Now in a smaller package or a smaller case size." I haven't found a smaller GFI receptacle yet that fits all boxes comfortably.
 
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Old 04-24-15, 09:19 PM
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boss,
I don't remember the rule offhand, but any device wider than 1'' has a math formula for determining how much space it truly takes up. I've never had to do it however as in the commercial sector we usually just run a hot neutral and bond (if spec'd for it) from a jbox to the GFCI.
And one marrette doesn't count towards the fill. Every group of two marrettes counts as one conductor. So 1 marrette = 0, 2 marrette = 1, 3 marrette = 1, 4 marrette = 2 etc.
And in this particular situation, I don't see the harm in leaving the reds in there as they will not be terminated, but I'm assuming the OP has an 1104 or 2104 box so as pj said...
I haven't found a smaller GFI receptacle yet that fits all boxes comfortably.
 
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Old 04-25-15, 05:10 AM
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The NEC considers a gfi or dimmer the same fill as a single pole switch, even though it is physically much larger.
 
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Old 04-25-15, 05:15 AM
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I would strongly advise against cutting off the reds. This destroys a perfectly good circuit, replacing the equivalent of two 15 (or 20) amp circuits with one 15 (or 20) amp circuit. Who knows that someday soon you will run into the need for another circuit? Could you install a brand new circuit (two years from now) for less than the cost of a 2 pole GFCI breaker (now)?

By going the route of the GFCI breaker you preserve the existing ampere handling capability, get GFCI protection, and also keep the existing receptacles and avoid the problems of box fill or cutting in new two gang boxes.
 
  #12  
Old 04-25-15, 12:33 PM
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boss that surprises me. I've gathered from reading posts on this site that the rules making an installation more difficult and expensive we generally adopt from the US (afci's everywhere just showed up for us, neutrals in each switch box is new, haven't confirmed it but heard we adopted smokes in every bedroom etc.). This is only the second time I've heard of the NEC being more lenient (I've gathered the NEC allows more receptacles per circuit).
I would also like to stand behind allan on this. I advise again to keep the splits and get a GFCI breaker.
You will have more power in your kitchen this way.
ex: You have 4 appliances plugged in to two receptacles on the same circuit drawing 6A each. Lets say your or the wife is doing some heavy cooking. Changing to a 15A circuit, you're drawing 24A and tripping the breaker. Putting in a 20A circuit, tripped breaker. 15A splits, you have 15A available on the top receptacles and 15A on the bottom receptacles and will be drawing 12A out of each. No trips.
 
  #13  
Old 04-25-15, 12:55 PM
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Correct, the NEC does not have a limit on number of devices on a circuit. Some areas do have limits as to the loads they serve like bathroom receptacles, but even those can serve an unlimited number of bathrooms.
 
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