Creating a duplex outlet from two 20A feeds

[Sherlock.Homes]

I've got a new microwave that requires bringing another 20A circuit to the kitchen. I have a Leviton 20A outlet (model J-2651) that I want to "duplex" so that 40 amps comes to the box from two different 12/2 w/G cables from two different breakers (20A upper/20A lower outlet).

I see a thin strip of metal which I believe is called the bridging tab with a narrow gap running between the two outlets. I assume is what I need to cut to bring one circuit to the lower outlet and another to the upper outlet.

The question is how best to cut it. Dremel? Remove the plate from the outlet and use wire cutters? Needle-nosed pliers?

I also assume I need to check afterwards with an ohmmeter to insure cutting the tabs really did isolate the outlets from each other.

I've also read for safety reasons the two circuits should be fed from a tandem breaker so both circuits are de-energized when shut off or tripped. That sounds right. Is it? Does the outlet need to marked to indicate the dual-circuit feed?

One site I looked at said not to disconnect the neutral bridging tab, only the hot side? Right or wrong or makes no difference? My inclination is that it has too be cut, too.

I recall reading a dual-feed 40A outlet is standard technique in Canada but is it legal in the US?

Is it just best to bite the bullet and gouge out another hole in the plaster to install a completely separate outlet?

SH

[gfretwell]

Yes, if you break the tabs, you isolate the receptacles. Usually you just grab them with pliers, wiggle it back and forth and it will break off. The only issue might be box fill.

[John G]

The tabs break off very easily. You can cut them off or use needle nose pliers to bend them forth and back.

You will need to use a two pole circuit breaker for this set up so that both sides of the outlet are de-engerized for servicing.

John Grabowski

[Sherlock.Homes]

Thanks. Agree re: box fill but this is a "end of circuit box" with only one wire entering it (for now). Also selected this particular Leviton outlet for both the 20A rating and because it was called either narrow or shallow or somehow implied it was smaller than average. I doubt box fill will be an issue but now I am more concerned if the outlet needs to have a tandem breaker if two different circuits are feeding one outlet.

SH

[gfretwell]

I agree with John's suggestion that you should have a tandem breaker or even 2 breakers with a handle tie but if you are not sharing the neutral, it is not code. It does create a danger tho if you do not get both turned off before you go into that box. It should be easy to move breakers around to get them next to each other so you can handle tie them.

[clare]

The tabs snap right out with whatever pliers you have on hand, or even a slot screwdriver. When the link is out, it's out. To be "code comliant" you want to use a ganged (240 volt type) breaker so when the breaker on one side is off the other one is too - and then you may as well just use a single 12/3 cable in an "edison circuit" It IS legal in the US as an edison circuit. Using 2 12/2 cables MAY be legal, but only with a twinned or ganged breaker from my understanding.

[clare]

It DOES need a "linked" breaker -at least anywhere I've seen it done. Basically you install a 240 volt circuit and split it at the outlet (edison circuit)

[Paintedcow]

I assume you will have to run another cable to that outlet. How do you intend to run that cable without removing plaster?

Simple solution: Remove enough plaster next to the existing box, to fit another box. That will allow you enough space to remove the existing box in order to attach another box to it (assuming it's a metal box which can be ganged). Before you install the ganged (double) box, run your new cable thru the wall. Put the ganged box into the wall, using whatever attachment method is available for your wall. (Of course feed the new cable into that box first).

Now you will have TWO separate DUPLEX outlets. Next to each other. Each will have a different breaker, but they can be standard single circuit breakers.

This is the RIGHT, and the EASY way to do it, and you get a total of FOUR outlets, not TWO in the end.

[Ralph Mowery]

In article , [e-mail] says... intend to run that cable without removing plaster?

That is similar to what I did. I needed a 240 outlet and some 120 volt outlets. I ran a 3 conductor with ground from a 240 volt breaker. Went to the 240 volt outlet and split from there to 2 duplex outlets. That gave me 4 120 volt outlets where I could draw 20 amps from each pair.

[DerbyDad03]

The same way it's been done millions of times in the past.

Why do you think plaster has to be removed just to run a cable to a box?

What makes it the "right" way? There is nothing "wrong" with a split receptacle.

[Sherlock.Homes]

pliers to bend them forth and back.

both sides of the outlet are de-engerized for servicing.

Thanks! One side of the bridge tab seems a lot easier to bend out than the other but if I muck it up I've got another.

Am I correct in assuming with a tandem breaker if one circuit pops, the other is shut off even though it's still OK? Does a tandem breaker show which circuit had the fault?

I'm beginning to see some advantages in bringing out the Sawzall and all the rest of the tools it takes to add a new outlet to very old plaster-lathe construction.

SH

[gfretwell]

That is one advantage of using 2 single pole breakers, handle tied. If you have one tripping you can remove the handle tie to isolate although in most designs it will be apparent. As I said before it is recommended in a box with multiple circuits but not required as long as you are not sharing the neutral.

[gfretwell]

The problem is, with a tandem, there is only one flag so if you are feeding two 120v circuits, you will not know which one tripped the breaker.

[clare]

Square D QO all the way. My QO panel, complete with breakers cost twice what a seimens or Homeline panel would have cost, but I won't have to replace it again in my lifetime.

[clare]

If they are on one "spit" outlet it doesn't take long to figure it out.

[gfretwell]

I am a QO guy too. A SqD rep gave me a box of 20a breakers 40 years ago and that was the best investment SqD ever made. My addition got a SqD panel just because I had those breakers and I have bought a shit load of SqD stuff since in 3 more houses. That was just about the only thing you ever saw in computer rooms although they were QOM as often as not (bolt in). That was why I got the breakers. He brought the wrong ones and I happened to be there talking to him. I managed to find a way to work around the problem and get him off the hook until he could get a box of QOM to them.

[gfretwell]

I didn't raise the issue, the OP did