mysterious outlet wiring question

[HamNCheese]

I'm trying to install a GFCI outlet on our (110v) washer and dryer. I turned off the breaker and confirmed that the outlet was off. The I opened the outlet: it has one red wire, and two white wires attached. I figured as usual red was hot, white neutral, with white looping on to some other outlet. But then I got a shock off the white wire. I measured the voltage between the two white wires and I get 110v. If I measure between the red and either white wire I get no voltage.

Can someone explain to me what's going on here? Are the colors just backwards? And why does the breaker turn off the outlet but I still get voltage on the line?

[Nate Nagel]

This sounds odd to me, how many cables are in the box and which wire colors are in the cable?

nate

[Toller]

That is with the breaker off, right? How were the wires connected to the outlet?

For the moment I will guess that the hot white comes from something that is turned on, so it has voltage. If you turned the breaker on you would see voltage on the red. But that is a guess, subject to answers to the questions.

[roger61611]

i had a light fixture sort of like this and the hot white was a ground coming back. took me an hour to understand that on earth the previous owner had done. i believe you should do some careful investigating before making any assumptions, like why the heck you got one red and two whites - you should have one black and one white, or 2 of each if the circuit continues on.

you should not see a red wire except for a 3-way switch. it really sounds like some previous owner jacked the thing up and now you get to figure it out...

[Toller]

That's not true; there are several reasons why there would be a red wire. Now the two white wires are odd, but not the red wire.

[HamNCheese]

OK, you're onto something here. Here's some more info.

Yes, if I turn on the breaker, I get 110v between the red wire and

*one* of the white wires.

If I test between the red wire and the *other* white wire, I get 220v.

If I test between the "hot" white wire and ground (the outlet box) I get 110v.

Next I turned off the breaker to the refrigerator, which is on the other side of the wall of the outlet in question. Sure enough, the "hot" white wire on the washer/dryer outlet went dead, too.

So is this a case where the refrigerator closes a circuit and sends power through the white wire which is then looping on to the washer/dryer outlet?

And now the question beckons, (a) is this dangerous in any way, and (b) how am I supposed to hook up a GFCI outlet to this line? Is it even possible? I'm also wondering if I put the GFCI on the refrigerator outlet instead, is the washer/dryer outlet considered downstream of it so that I would get GFCI protection on both circuits?

[RBM]

What you have is an incorrectly wired Edison circuit. There are two circuits sharing that neutral. You only killed the one circuit, so when you disconnected one neutral, you got a shock as the other hot of the circuit was unable to return through the now open neutrals. To wire this properly, the two neutrals cannot be dependent on a device, they must be spliced together then pigtailed to the outlet.

[HamNCheese]

If the two white wires are connected to the same outlet terminal, as they were, isn't this doing what you mention?

[HamNCheese]

And is it possible for a GFCI be placed on this circuit, or on the other outlet that is sharing the neutral, or on both?

[RBM]

The danger, and the reason the neutral can't be dependent upon a device, is that if there is an open neutral situation, you get a 240 volt circuit feeding 120 volt devices. It is much more reliable to splice them independently and pigtail the outlet. Yes, you can install a GFCI on either of the circuits

[Toller]

Correct. Presumably the refrigerator is not able to run unless the two white wires are connected?

Only if you don't know what is going on. I don't like multiwire circuits for that reason. A previous owner of my house changed the breakers so that both were on the same leg. Could have burnt the house down.

Just wire it normally. Both white wires go to the input side; or pigtail them as someone else suggested.

You probably don't want a GFCI on a refrigerator, and it wouldn't affect this circuit anyhow.

[HamNCheese]

Haven't I created an open neutral situation by disconnecting this outlet and leaving the hot return wire disconnected?

[RBM]

The only wires you want to keep together are the whites. There are two circuits involved, the red wire was on one of them and in the box, you'll find two black wires spliced together, they are the second circuit

[RBM]

Just to clarify: It is a code violation to connect both Neutral wires (of a multiwire) to any outlet or device, they must be pigtailed or connected so as not to be dependent upon the device

[hallerb]

Washing machines will false trip GFCIs and like refrigerators and freezers arent required to be on a GFCI.

been there done that.

[dicko]

I thought it was code that both breakers of an Edison circuit had to be ganged together so what just happened here cant happen. Is this true?

-dickm

[Doug Miller]

No. The U.S. NEC requires tied breakers only if there's at least one device on the circuit that's supplied by both legs (e.g. a duplex receptacle with the tie-bar removed on the hot side, and each half of the receptacle supplied by a different leg).

IMO that's a serious flaw in the Code -- I think tied breakers should *always* be used on Edison circuits.

[Toller]

No, it isn't. Should be, if only to ensure it actually IS an Edison circuit.

[w_tom]

I am not sure if this is what you have. But upon first reading, this sounds like a shared neutral. If refrigerator and washer/dryer are not on separate phases, then a very dangerous fire hazard exists. Both circuits should be a dual circuit breaker so that if one circuit trips, then both trip.

If both circuits share a common neutral, then a GFCI in the circuit breaker box with constantly trip and both circuits must be GFCIed. But refrigerators must not be on a GFCI according to code.

If it is a shared neutral, the best solution is to run a new circuit either to refrigerator or to washer dryer. A shared neutral must be performed with care to avoid fire.

[Don Young]

Yes, you created an open neutral by disconnecting the receptacle. The neutrals should be pigtailed together so this cannot happen. You saw what kind of hazard opening the neutral can create. Your wire routing is incorrect if the black wire feeding the refrigerator does not come through this box but everything will work normally if you just pigtail the white wires and connect the pigtail to the line neutral terminal of the GFCI outlet. Connect the red wire to the line hot terminal of the GFCI outlet. Connect the ground, if used. All will be fine.

Don Young