Wiring Question - three wires, two hot.

[Louis McEniry]

Hello,

I dabble with electrical. And generally, I will 'copy' existing wiring so I don't screw things up too much. I thought I was being very carefull to do this in this case.

I moved a recepticle through a floor to have an extra plug in my bedroom. I wrote the wiring scheme of the receptacle down so I could duplicate the wiring upstairs.

It was a three wire, 12 guage, receptacle. Why its three wires, I don't know.

The scheme on the back of the receptacle I though was:

Left side Right side Black White

Red

From the fuse box, the black and Red wires were each on its own fuse, ie both hot....again why, I do not know.

The problem is that the above scheme doesn't work... I can input one fuse, but when putting in the second, it blows.

Can anyone help me ???

Thanks!

Louis

[HorneTD]

Louis You have a multi wire branch circuit. The two receptacles are intended to be on separate circuits. There is a small tab that connects the two terminals to each other on each side of the receptacle. Use a needle nosed plier to break off the tab between the black and red wires on the brass screw side of the receptacle and you will eliminate the 240 volt dead short you have created across the two brass screws. If you look at the old receptacle very closely you will find that it had the connecting tab on that side of the receptacle removed.

-- Tom H

[Jeff Prevett]

What you have is a split-recepticle. Without getting into too much detail, when you put in the second fuse, you esentially created a short circuit across the two 120-V lines running to your house (the two 120-V lines are

180 deg out of phase, so the maximum voltage between the two tines is 240 V). To have this work properly, you have to break the connection on the side of the recepticle. There will be a tab connecting both screws on each side of the receptacle; break ONLY the one with the brass screws and attach the red and black wires as you did before.

However, you might have broken many code violations when you moved this outlet. Was the original outlet in a kitchen? (there are few places that have to have a split-recepticle). Assuming you are in Canada, each plug over the kitchen couter MUST be on it's own fuse. Note, each plug, so a normal duplex recepticle must be 'split' into two circuits (hence split-receptcle). It also cannot be shared with any other room.

Jeff

[Matt]

Louis -

What was the red wire hooked to before? If nothing, then it perhaps was run to feed an additional future circuit, but that's unlikely. Another guess is it could have at one time been a 220v outlet, changed later by someone to a 120v.

Is there a seperate ground (bare) copper wire?

If so, cap the red wire, shut off and put some elec tape over the breaker connected to the red wire, or label it such that you don't turn it back on later. (If the red and black wires are connected to a single breaker, then this was at one time a 220v circuit - I'd recc you call an electrician as the breaker needs to be pulled and replaced with seperate individual ones.

Then hook the bare wire to the ground screw, black wire to brass screw (right side, as viewed from the front), and white wire to the silver screw (left side).

[Matt]

Or, what Tom said!!!!

[bill a]

Like Tom said, the receptacle buss was probably split, and a common purpose for this is to have one of the two receptacle sockets on a light switch, with the other socket on the usual type of circuit. The wall switch in the room would control a table lamp or whatever. hth bill

[HorneTD]

Louis A couple of questions. Do you live in Canada? Did that receptacle serve your kitchen at one time?

-- Tom H

[Bennett Price]

It sounds as if the original receptacle was wired for two hots (black and red). This is done, illegally I think, by breaking the little strap on the receptacle that connects the two hot brass screws. (The white neutral should go to the tin plated screws, the hot to the brass - the short blade on the receptacle should be hot, the long blade should be neutral.)

I th> Hello,

[Professor]

Electricity is not something to dabble with.

[Matt]

Aw, I disagree. It's got:

Intrigue (how the hell do I do this) Drama (did I do it right) Action (I'm doing it) Suspense (will it work) Fear (where is the smoke coming from) Comedy (ZAP! uh, guess I should have turned off the breaker) I think electricity is the most dabblistic of em all.

[Noozer]

Illegally? I don't think so. It's quite acceptable to feed single outlets on a dual recepticle from multiple circuits - if done correctly.

Sounds like it was originally wired properly and most likely to feed a kitchen outlet.

[Joseph Meehan]

I don't think so, but I could be wrong and I would want to check it before I did it. It is required to use the double breaker when wiring a

240V circuit, but this is two 120V circuits.

[Wayne Whitney]

Doesn't doing this require that both circuits be protected by the same circuit breaker, i.e. a double-pole breaker? It soounds like the OP had separate OCPDs on the two legs of the multiwire duplex receptacle.

Cheers, Wayne

[Louis McEniry]

Hi Matt,

Yes there is a separate ground.

It was just a receptacle in a basement 'kitchen' area. ....Its funny...I am confused but there was a 220 volt plug in the same area for a heavy heater...but I think that was changed also...so I was a little confused by the plug itself. So as far as I know it was just a regular receptacle. Also, I didn't mention, but I think the 'branch circuit' idea is correct because I am having trouble getting one other light to work and I think there may be a connection between the two.

I had capped the red wire yesterday out of desperation...but now I will check the side of the receptacle, clip it, and reconnect the red.

Thanks a lot.

Louis

[Louis McEniry]

Hi Tom,

Yes I am in Canada. And yes it served a secondary kitchen area in my basement.

Louis

[Louis McEniry]

Thanks Matt...

I agree..its fun.

So long as you know enough to wire according to code and be super careful.

[HorneTD]

In new installations all of the devices on a yoke or strap must be deenergized by a single switch, breaker, or pull out but that requirement is relatively recent. There is no requirement to alter existing circuits when the code changes.

-- Tom H

[Louis McEniry]

Yes, I think that is the most likely answer.

Thanks again to all for your help.

Louis

[Wayne Whitney]

OK, but I believe the OP was moving a split-circuit receptacle. I would assume that this requires meeting the new code requirements.

Cheers, Wayne

[Matt]

Hmmmm no problem man!

But, as you probably know -

Clipping the receptacle will not get your other light working.... if the work you have done is related to the now non functioning light, you need to find the lead that feeds the other light and get it some juice. Good luck!

Matt