Miswired receptacle.

March 23, 2010 1:11 PM

This switch/receptacle has been miswired for years. For starters, neither device had the grounding wires attached. I want to put things the way they should be.

I always wanted to replace the receptacle (see below), but the switch recently died in a little wisp of smoke.

I've already replaced the switch; the only problem there was that I couldn't find one with the screws on the left, so I had to tape over them (good practice to guard against shorts, especially in a metal box).

The receptacle has a broken "lip" on top, meaning 3-prong cords don't stay in place, and the lower receptacle has always been strange in what it would power and when (e.g. trouble light worked fine, vacuum no). Now that I look at it it's almost as if it is supposed to be controlled by the same switch as the ceiling light. I don't remember that being the case and it seems wrong. I can reconnect and try this out if there's a question.

Here's how it looked as I opened it up. The outlet is in series and so I expect one lead coming in and another going out, but there are actually two wires connected to each screw. This other view shows the other side of the outlet and here is more of the wiring itself.

(If necessary I could sketch an actual wiring diagram.)

Ideally I could connect everything exactly the way it was, but I have low confidence that it's the way it should be. The new outlet doesn't give me enough room for all these wires, so should I use pigtails to make the connections? Do the wire colors seem to make sense? Do I need to test the wires for correct hot and neutral? It looks to me like going up into the conduit we have a white and black on the right, and a white, red, and red (?!) on the left. (To me, a three-way switch needs white, black and red, but this isn't three way!) The right conduit is the ceiling light, the middle conduit is the garage door opener, and the romex goes to an outdoor outlet.

Obviously basic electrical safety being practiced here -- breaker off, testing for liveness, etc. I've replaced switches and outlets before but never had to really rewire one. I have a multi-function tester but I'm not sure how to apply it in this case.

Maybe I really need a pro to sort this out?

posted by dhartung to home & garden (14 answers total)

Three questions before we get started. I can't see what is coming out of the supply conduit. Is this the one you describe as having red, red, white? Second, do you know where the supply wires are coming from? By that I mean, are they coming from another outlet box or are they coming from the panel? If from the panel, are the reds coming from separate breakers? Third, what do you see when you take off the cover of the box that is where the garage door opener gets its power? Do you see one white and one red feeding it?

We can work from there.
posted by Old Geezer at 3:14 PM on March 23, 2010

Well that's not to spec. (IANAE)
Hmmm. How is the garage door opener controlled? Does the switch in your picture control anything besides the ceiling light? Because if it doesn't what I would probably do (if my guess is correct) is go ahead and buy a breaker and connect the garage door opener directly to your panel. I think what is going on is that the light and garage door opener might be tapped into the Romex line. But I can't tell without more detail.

OP: I'll be following along with you and OG.
posted by vapidave at 3:24 PM on March 23, 2010

First: Yes test for neutral, ground and power. Do this whenever you open up a box of unknown providence, never can tell when someone in the past has been stupid.

Second: Where does the wire coming into the bottom of the box come from? I can't tell from the photos; is it two or three wires? I'm going to assume the white taped off wire was connected to the outlet with the other white wires (I think this is what you meant).

It looks to me like power is coming in from the bottom. It is routed over to outlet and then power is fed to the switch, the garage door opener, and the outside outlet. From the switch it goes to the light. The second red wire feeding directly from the outlet to the light conduit is to power either a ceiling fan or the light box is being used for a junction box and the red wire is connected to something else farther down stream.

If it is as I speculate there really isn't any problem outside of general workmanship. IE: The lack of pig tailing and the two red conductors in the centre conduit not being differentiated with tape. By Canadian Code even the garage door opener being fed from a general lighting circuit is ok. The Code requires an outside outlet to be on it's own circuit but as long as you have at least one outlet like that the others can be tapped off of any general lighting and outlet circuit. Even a third horse garage door opener only pulls a 1/6th of the amps the breaker is rated for.

"The new outlet doesn't give me enough room for all these wires, so should I use pigtails to make the connections?"

Do this anyways. Unless the receptical is split then there ideally should only be a single wire going to each side. PS: Don't use back stabs (the wire connection from the back) only the screws.
posted by Mitheral at 4:21 PM on March 23, 2010

Working on this. Yes, the red-red-white comes up from the conduit. I have found two romex lines in the basement that enter the crawlspace near there. The right conduit, I was wrong, supplies a baseboard heater that was disconnected 20 years ago, and possibly the receptacles in that wall? The opener is just on a plug, after all, on the same conduit as the ceiling lamp. I don't think this needs another breaker -- I don't have a place for one as it is.

The romex to the outlet (far left top exit) is really just a stub/tail/dead-end so I consider it extraneous/secondary to the main problem of the weird connection.

Took photos, analyzing, trying to diagram....
posted by dhartung at 4:41 PM on March 23, 2010

OK, here's a diagram. I've simplified it by treating the romex outlet as disconnected (instead of connected to either side of the top outlet face), and straightening out the various loop-de-loops.

So I see how R5/W4 is probably running the ceiling outlet (opener) and W4?/R4 are running the ceiling light via the switch. You want W4 to get continuous power via W1, and R5 stays live via the unbroken receptacle tab and R1. And then B2 is obviously tied directly to R2 by the pigtail.

But I can't for the life of me figure out how W3 was powered. I really thought that lower receptacle face sometimes worked, but maybe it really doesn't.
posted by dhartung at 5:44 PM on March 23, 2010

Here's what I see. The center conduit has red, red, white going up. It shares a common white (which isn't terrible, but not that good) with the garage door opener and the light. The hot side is being fed by the reds, one to the opener and one to the light. The red from the switch feeds the light. The Flickr photo to the left of the one with your finger in it appears to show the white wire from the center conduit going to the outlet on the common side. This is good. The conduit from the bottom appears, once again, to have two hot conductors (red) and a single common ostensibly returning to the panel. One of the reds powers the circuit with the wall heater and the possible outlets in that room and is wire-nutted to the black wire in the right-hand conduit. The second red appears to power the outlet in this box, the garage opener and feeds the swith to the light.

If you were to replace the outlet and wire everything back the way it was, it appears that everything would be O.K. I am concerned, however, with the fact that whoever wired this stuff in was using red conductors indiscriminately. A quick inspection by a qualified electrician is probably in order just to see what other nightmares may lurk.
posted by Old Geezer at 5:54 PM on March 23, 2010

In your pictures it looks like the the two silver screws are connected together via breakaway tab. There isn't a good picture of the hot side of the outlet to see if that is also the case though your diagram says the tab is missing. If it is indeed broken then they wired it this way to get to independent circuits at this location. There are some good reasons for doing this but without knowing the purpose for this room when it was wired that way it makes it hard to tell exactly.

W3 (which should be a neutral) was powered B2 which of course is connected to R2. R2 should lead back to a breaker. And, unless there is something funky going on, a meter put between R1 and R2 should read 240Vs. A meter between either of R1/R2 and W1 should read 120V.

Old Geezer is right that the two red conductors should be discriminated from each other. The common way to do this is with electrical tape wrapped around about the last six inches one of the circuits at all ends.

PS: Your situation is a prime example of one of the reasons why one should always pigtail. The romex probably was a later add on, the person didn't have enough terminals to make a safe connection so the made a potentially dangerous and definitely unclear connection instead. Also if there is indeed 240 between r1 and r2 a seriously dangerous condition can be created at the heater if the outlet next to the switch fails in the right wrong? way if the outlet isn't pigtailed.
posted by Mitheral at 6:12 PM on March 23, 2010

OG: There are other nightmares. This was part of a 1970s wiring job that only partly spruced up a lot of ancient wiring in a house that itself dates to 1858.

Mitheral: Yes, I agree on the pigtails. What you can't see in the photos is that the outlet actually uses a mix of screw connections and backstabs. Crazy. I was also worried that there might indeed be a 220/240 circuit sort of hidden in this mix.

I guess I'm wrong about the tab, and the outlet isn't actually split. Could you elaborate, though, about the dangerous condition (I assume you mean a short to ground of some kind)? And what did you mean by "between R1 and R2"?

I will wrap -- would it make sense to wrap R2 and make it black like B2? And what about R5?
posted by dhartung at 6:38 PM on March 23, 2010

dhartung writes "What you can't see in the photos is that the outlet actually uses a mix of screw connections and backstabs. Crazy."

Yet distressingly common.

dhartung writes "Could you elaborate, though, about the dangerous condition (I assume you mean a short to ground of some kind)?"

If R1 and R2 are set up to share neutral W1 they should be drawing from opposite power legs in your panel and the potential between them (In volts mode put each lead from your meter on one of R1/R2) will be ~240V. Between either R1 or R2 and W1 you should get ~120V on your meter (IE: standard wall outlet voltage). Both R1 and R2 can carry 15As of power and W1 only ever sees the difference in Amps between R1 and R2. You should also see ~120V between either of R1/R2 and ground; and 0V between neutral (W1) and ground.

98% of the plugs in my new shop are wired this way because it uses less wire so even though 14/3 is more expensive per foot you can use less of it. I also got to drill 50% less holes and used 50% less knock space in my sub-panel.

The danger comes in when the neutral is broken some where along the way (by for example a non pig tailed outlet that breaks or is removed from service without reconnecting the wires). This results in no neutral connection at down stream plugs and potentially 240Vs on what is supposed to be a 110V outlet. The former is a shock hazard for people and the latter tends to be very bad for what ever is plugged into the outlet.

The funky and dangerous comes when R1 and R2 are on the same power leg back in your panel. If they are attached to the same breaker than there isn't a problem per se though I'd deke one of the wires out. If they aren't attached to the same breaker and they are sharing the same neutral then instead of the neutral W1 seeing the difference in amps carried by R1 and R2 W1 will see of the Sum of the amps being carried by R1 and R2. Plug your hair dryer into R1 and the electrical kettle into R2 and W2 is seeing 25-30 amps which long term is well above the melt and catch fire rating of the wire. Neither breaker will trip because individually R1 and R2 are carrying safe amps.

Looking at your diagram again I'm going to bet the tab on the hot (IE: bronze side) of your receptical is in place. The person who wired this box used the outlet as a junction. If the tab isn't in place then you've got something pretty weird going on. If the hot side tab is broken then the only thing that makes sense is power is being supplied by R5 from someplace else. And if the ultimate source of that power isn't one of the breakers supplying R1 or R2 then you've got the dangerous, potentially wire melting, problem I outlined above. The latter would be hard to do by accident so is pretty unlikely.

dhartung writes "I will wrap -- would it make sense to wrap R2 and make it black like B2? And what about R5?"

Wrapping R2 would be the simplest here. You need to mark R2 back in your breaker panel too (shut of the main disconnect on the panel before removing the access panel). You also should try and wrap R2 where ever else it might be.

If the outlet's hot tab isn't broken and then R5 is an extension of R1 and wouldn't be wrapped. If the tab is broken then you'd have to see where R5 comes from.
posted by Mitheral at 8:51 PM on March 23, 2010

Also re-reading your initial question you said "(e.g. trouble light worked fine, vacuum no)". This symptom, while likely just a defective outlet, could be caused by a floating neutral (the non funky danger above; your light bulb will work on 60 or 200Vs and your vacuum won't). Test your outlet and whatever is switched thoroughly with your meter to make sure the correct voltages are observed when you are done. You should have 120V between the narrow and wide holes, 0V between the wide and round holes and 120V between the narrow and round holes. You should, assuming the tabs are in place on both sides of the receptical, have 0Vs between the two narrow slots. You should also have 0Vs between the two wide slots.
posted by Mitheral at 9:00 PM on March 23, 2010

Mitheral, thanks for that thorough answer!

And I guess I get to give the multimeter a thorough workout.

As to R2, the scary thing here is that I may have just worked on this thing partially hot. Am I correct that if one of the circuits is off, though, I'm only facing 110V?

The person who wired this box used the outlet as a junction.

Yeah, once I simplified to the diagram it made more sense. I would still expect that the supply would come in to either side of the bottom and then leave by either side of the top, though, for sanity's sake. To that end:
* W1 and R1 will be connected to the bottom
* I will add pigtails on the top and then run them to the various points
** How do I handle the need for multiple exit leads? I've only ever seen three in a pigtail. And I don't want to overcrowd the box.
* I have identified a basement junction box where I believe R1 and R2 are routed out to the garage.

I'm going to carefully test for the non-neutral condition, because that could explain why the garage door has been wonky as well. It burns out rough-service bulbs really fast and it does a lot of unexpected reversing. My next project was to replace it with a new one, but now I worry that we've had the high voltage condition there for ... well, for years, and it's just killing everything. Nobody's been shocked, though (that I remember).
posted by dhartung at 10:06 PM on March 23, 2010

dhartung writes "How do I handle the need for multiple exit leads? I've only ever seen three in a pigtail. And I don't want to overcrowd the box."

You can have as many wires as you need come together in a single wire marrette; just make sure the marrette you are using is rated for that number of conductors. For example orange marrattes will handle 3 #14 conductors, yellow 4 #14, red 5 #14. Check your package though, different companies have different colour codes. The chart will be hard to read because it includes combinations of several different wire sizes so just look for the line with just #14.
posted by Mitheral at 7:51 AM on March 24, 2010

Ah, yes, the colors! Forgot about that.

I tested voltage at the outlet here and the ceiling and all registered 124V. Most of the time I did this, though, as soon as the leads made contact the garage door opener went "pop", and I smelled a bit of electric smoke, so I suspect it has an internal short and I unplugged it.

Tracing the supply back to the breaker is going to be f-u-n. There are at least three rats-nest junction boxes along the most logical route.
posted by dhartung at 1:36 PM on March 24, 2010

FYI, outdoor temps have not lived up to forecast, so I won't be working on this until it warms up a bit.
posted by dhartung at 10:30 AM on March 26, 2010