Code Question

Feb 06, 2004 38 Replies

Is there any reason why I can't have two outlets in the same box with each outlet on a different phase? I would like to take a standard duplex outlet, split it apart, and run a neutral and a hot to each side. The other end of the hots would go to a ganged circuit breaker. Before you ask, its for X10 diagnostic purposes (to measure/inject the X10 signal on each phase, right at the service panel).


Outlets are often wired this way, usually using three-conductor romex. There is no code restriction.

It is called "edison circuit", and in fact is code in canada for kitchens.

Works fine, and allows both outlets to pull full power.

I believe you can do it with one pair of outlets, by removing the ear on one side so the top and bottom are on different phase.

I agree. We have several kitchen outlets wired that way; by removing the ear between the upper an lower 'live' side of the duplex outlet and wiring with three wire (plus ground). Conventional, in this part of Canada anyway; ground is bare copper, white is neutral, black is one of the 115 volts 'legs' and red the other 115 volt 'leg'. A double pole circuit breaker is used at the panel to protect/disconnect both legs simultaneously. It may be wise to adopt a convention for all such outlets wired that way such as "Red wire to the top of the outlet, black to the bottom, etc." It basically doubles the capacity of that outlet (or run of outlets) for a very slight additional cost of wire. And we can argue about the extra cost of a double pole breaker versus another run of outlets? I've never seen, other than a single phase 115-0-115 supply, in North America, to a single family residence etc.? It's basically a centre tapped single phase from the distribution transformer. This provides 230 volts, single phase between the two 115 volt legs for heavier appliances. So the terminology 'leg' rather than the sometimes used 'phase', would be much more correct IMHO. Terry.

Might be a good idea to place a note in your breaker panel saying the tie bar'ed breaker is for that outlet and that it is not for a 240V circuit.

This is good if you sell your house, etc. Then the next person know what's going on...

A tied breaker should be enough, it isn't even required by code, but is a very, very, good idea that all power in an outlet box get shut off at one time, since most humans expect that to happen.

Inside the breaker box, wrap a piece of the same (different than the wires) color on the wires that make the edison circuit, so that they are identified as a pair. For example, the black and red wires with the blue tape on them are a paired circuit.

By simply changing from a 115v to 220v outlet, a future owner could have a 220 outlet.

Interesting.

Down here code dictates a GFI installed if within x distance from water, maybe other circumstances. I just GFIed all the kitchen.

If an edison circuit were used in a kitchen in a duplex box both outlets would have to be a GFI. ?

No, you have to use a tied GFCI breaker ($125) per outlet.

That is why I went with the US standard of a single 20 amp circuit, to each GFCI outlet ($10).

Given that I've gone from 15 amps total, to 55 now in the kitchen outlets, that should hold me.

Apparently, up in the "great white north", they use hi power electrical kitchen appliances more often, and need to plug more stuff in.

IMHO, the 20 amps per duplex outlet will be fine.

Or use the new(er) 12-2-2 with ground Romex that's on the market now. It's usually intended to supply two AFCI circuits since tied AFCI breakers aren't available yet. The cable contains 2 hots, 2 "neutrals" and an equipment grounding conductor. But then the first outlet box would have to have double duplex GFCI's receptacles, if the CEC allows that.

You can use a GFI outlet (or 2) on an edison circuit. Run your 12/3wg wire from a 2-pole breaker to a 2-gang box in your kitchen and put 2 GFCI devices in it. Beyond that point, you no longer have an edison circuit. Run a 12/2wg cable from the "LOAD" side of each device, and if you feed split duplex outlets from the circuit (as is done in Canada), you will have to remove the neutral tab between the silver screws as well as the hot tab between the brass-colored screws.

Best regards, Bob

According to John Hines :

The NEC is a quite confusing here, but, you should assume that a tied breaker _is_ required for a split-phase duplex receptacle on a common neutral circuit or even if you're doing your duplex receptacle with two independent neutrals. If you had _two_ duplex receptacles with independent neutrals in a box, then you probably don't need a tied breaker. But I think that's dumb.

The CEC is more anal, and insists that all circuits feeding a box (short of metal separators yadda yadda yadda) get disconnected at the same time, common neutral or not. So there's absolutely no question here.

According to volts500 :

_Pair_ of outlets. NEC and CEC permits "alternate counter outlets" to be off the same common neutral circuit.

Not necessary to use that exotic a wire.

Install a double box near the panel. From a tied breaker in the panel, wire ordinary 12-3 or 14-3 to the double box. Install two GFCI outlets, one on each hot leg, and split the neutral _before_ connecting to the "line" side neutrals of the GFCI's.

Then run two 14-2 or 12-2's to the kitchen counter outlet[s] from the "load" side of the GFCIs. Don't confuse which neutral goes with which hot. Cut _both_ links on the duplex, and wire one cable to each half of the outlet.

An inspector may grumble, but would probably pass it once it's explained that you're simulating a $100+ dual GFCI breaker with

Romex is not allowed in my jurisdiction. So I'm using 1/2" Greenfield and 12ga str wire.

It IS code that when 2 circuits feed a device on a single strap, a tied breaker is used. SO in this example of an edison circuit feeding the upper and lower

1/2's of a duplex receptacle, code would require that both breakers open simultaniously.

IF however, the edison circuit split at the 1st box, feeding 2 seperate circuits where a bunch of duplexes were on one circuit, and a different bunch on another, and at no point (especially the 1st outlet) were the 2 circuits on the same device, then the breakers need not open simultaniously.

Geez, what size boxes are you using for a typical, middle-of-the-run outlet with 12/2 in, 12/2 in, 12/2 out, 12/2 out and a device?

I wouldn't string 'em together like that. But if I did, a 3.5" deep box might handle it.

I'd wire every other duplex outlet on alternate legs of the circuit, or else I'd put a GFCI for every device and never run anything off the LOAD screws. If I *needed* a split duplex outlet somewhere, I'd make sure it was an end.

Bob

There are some tricks that might make it possible. It'd certainly be painful. In Canada, you'd probably not be using 12ga at least.

Not using split duplexes for kitchen counter outlets is not an option in Canada. They _must_ be split.

Geez Chris, are they that inflexible? How about 2 duplexes in a 2-gang box, would the 2 tops need ckt #1 and the 2 bottoms need ckt #2?

Otherwise, I'd use a 4" square 1900 box with a 1 gang plaster ring to make it easier to work with 2 sets of 12/2 NM cable.

How many countertop outlets do you need? Three? Use deep boxes and extra-heavy-duty backwired devices (because they are easy to work with.) Two 12/2 cables in and one 12/2 cable out of an extra deep 2x4" box -- each box feeds out the opposite leg of the circuit. Then these two outfeed cables feed into the third outlet box which is a dead end.

Best regards, Bob

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