Two quick "back wire" receptacle questions

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  #1  
Old 07-12-07, 06:20 PM
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Question Two quick "back wire" receptacle questions

I'm replacing some receptacles in my house which have been damaged.

I purchased a box of ten "back wire" (not back stab or QuickWire) receptacles... the kind where there are holes in the back and screws which tighten a plate to hold the wires in place. I read here on the forum that these give a connection as good as the screws (and much better than traditional "back stab" connections.)

I noticed that there are two holes per screw on the back--4 brass and 4 silver for a total of 8--compared to the 4 of a "normal" cheap receptacle.

1) I assume the top two holes on each side are associated with the top screws and the bottom two holes are associated with the bottom screws? (Meaning that it does not matter which hole I use from each pair?)

2) Some of the existing receptacles I'm replacing were wired by the previous homeowner with multiple wires on a screw. I know this isn't to code, and of course I'll fix it.

Normally, I would fix this by pigtailing behind the receptacle (so that there are no more than one wire per screw.) But with the 4 "hot side" holes on the back, can I just use 3 of the 4 holes and eliminate the pigtail? It seems like this is the equivalent to "two wires per screw" except without the problems of worrying about a screw holding two wires in place.

Your wisdom is appreciated as always!
 
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Old 07-12-07, 07:32 PM
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wire per manufacturer's instructions. although, I would pigtail, reason being...if that device fails, it is going to affect all downstream recepticles as well
 
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Old 07-12-07, 07:44 PM
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Unfortunately, there are no manufacturer's instructions (at least not that I can find...)
 
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Old 07-12-07, 07:54 PM
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Yes, you can use all four wire locations. I would not pigtail unless I had more than four to connect. Receptacles rarely fail in a residence in such a manner that will cause the connections to be broken.
 
  #5  
Old 07-12-07, 09:27 PM
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Thanks for the reply! I just finished my first replacement, and it actually had 4 hot and 4 neutral, so I had to use all 8 holes. The back wire does seem to make a very secure connection though.

I had a hard time pushing the receptacle back into the wall due to the large number of wires in the box. Really, it was all I could do to push the receptacle back far enough to start to screw in... after that, the screws little by little pushed the receptacle back into place.

Is this OK? It seems like a tangle of black and white wires is suboptimal because if there's a crack in the insulation of one of the wires, there could be an undetected arc back there.

I don't know if there's really any alternative with so many wires in a single box though. Thoughts? Is it a problem if screwing the receptacle in is what pushes the wires back in the last bit?
 
  #6  
Old 07-12-07, 09:39 PM
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This is why Bob said pigtail if more than 4 wires. You should'nt have a problem though just a rather unorganized bunch of wires. One thing you want to watch out for is different size wires. The pressure plate sometimes will not secure the smaller wire.... say you had a #12 in one hole and in the hole below it is a #14. In a perfect world this shouldn't happen but the world isn't always perfect.

Roger
 
  #7  
Old 07-12-07, 09:45 PM
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Using the screws to daw it in is a bad practice. The yokes are thin and weak and it's very possible you can break the receptacle or contacts in side with such a load being as it was never designed to handle physical pressure.
 
  #8  
Old 07-12-07, 10:11 PM
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Thanks for the replies! Let me see if I have the alternative right.

As an alternative wiring to make more room in the box, I could pigtail all 4 hots together along with a new fifth wire which makes a single connection to the hot side of the receptacle, and then do the same thing on the neutral side?

(The tab isn't broken between top and bottom; they're on the same circuit.)

If so, would a five-port push-in type connector (like Ideal In-Sure) be a reasonable kind of thing to use for this?
 
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Old 07-13-07, 08:47 AM
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> If so, would a five-port push-in type connector (like Ideal In-Sure) be a
> reasonable kind of thing to use for this?

Yep. Those work great with 4 or more wires where wirenuts can really be a pain.
 
  #10  
Old 07-15-07, 05:28 PM
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OK, I did a half-dozen or so more of these this afternoon, and I'm getting the hang of the back wire and I'm doing appropriate pigtailing now.

One other question I couldn't find an answer to via searching: is it possible to overtighten the screws on the back wire receptacle?

I'm hand-tightening with a lot of force (the wires certainly aren't coming out), but stopping short of a screw-stripping amount of force.

The receptacles I'm using are "commercial grade" receptacles:

http://www.leviton.com/OA_HTML/ibeCCtpItmDspRte.jsp?item=9151&section=10925

I looked at the web site for them and in the box and can find no manufacturer's guidance for how much force should be used to tighten the screws.

Any opinions or guidance appreciated. Thanks again for all your help!
 
  #11  
Old 07-15-07, 06:39 PM
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I suppose you could buy a 200 dollar torque screwdriver. My opinion is to tighten as you are doing. Give the wire a little tug to make sure it is secure then your good to go. One thing that will get you is not stripping the wire enough and you get the insulation under the pressure plate. If so your wire is not as secure as you think.

roger
 
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Old 07-15-07, 06:57 PM
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Thanks for the reply, Roger.

I've been stripping the wire to 1/2" (which is what is indicated by the strip gauge on the receptacle) and even measuring with a ruler to make sure that I'm very close to right on. (1/2" is what is required by the Ideal In-Sure push-in connectors I'm using as well.)

So, hopefully, I'm not stripping too little. I don't see any bare wire coming out the back of the receptacle though... it's all insulation.
 
  #13  
Old 07-15-07, 07:11 PM
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I would say your right on the money and no problems. For your information the torque on the screws is 14-16 inch pounds.

If you thought I was kidding....

http://buy1.snapon.com/catalog/tools.asp?tool=all&Group_ID=16437&store=snapon-store

For some reason this site will not allow copy and paste and has become pretty much a bare knuckles format. It really sucks when you can't copy a link.

Roger
 
  #14  
Old 07-16-07, 10:55 PM
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One more question (if you'll humor me one more time...)

I've been assiduously wiring each receptacle exactly as it was previously wired and testing after every hookup.

So far, so good with everything.

But there's one receptacle I'm thinking might have been originally wired incorrectly based on my (admittedly limited) understanding.

It's in a bedroom, and it's a duplex receptacle where the top part is always hot, and the bottom part is switched. Coming into the box are two Romex 14-2 cables (so, two hots and two neutrals total.)

The previous receptacle was wired with the pair of wires from one cable on the top, and the other pair of wires on the bottom.

The part that I think might possibly be wrong: the tabs were broken on both sides of the receptacle.

My understanding is that the normal wiring configuration would be for only the hot tab to be broken unless each half of the receptacle is on a separate circuit. In this case, the two halves are on the same circuit (or at least, they're controlled by the same circuit breaker.)

That said, everything works as it should... one side is always on, the other works properly switched. My 3-prong tester shows correct wiring.

So maybe all is well... but I thought I'd see what you all thought and if you thought it was correctly wired. Thanks!
 
  #15  
Old 07-17-07, 03:31 AM
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Neutrals from different circuits are not tied together. It's a safety issue. In your case both tabs should be broken. On the other hand all grounds are tied together and if metal box pigtailed to both box and receptacle.
 
  #16  
Old 07-17-07, 04:17 AM
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I am curious about the wiring of this receptacle. You are stating two separate cables controlled the receptacle that you replaced, one the top the other the bottom. However, you are also stating that these are on the same circuit breaker. This is most unusual.

Could you please tell me the wiring at the switch that controls half this receptacle.

If indeed the four wires do come from two separate cables and you really do have two neutrals and to hot wires, then you should break BOTH tabs on the receptacle. This would not because they are on different circuits (they aren't), but rather because they are fed with separate cables.
 
  #17  
Old 07-17-07, 03:51 PM
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I put up some pictures to help make it clear exactly what I'm seeing and what I did:

http://headworld.net/pictures/electric.html

The first two pictures are just of the old receptacle showing that, indeed, both tabs were broken.

The next picture shows the wiring inside the box, as I described above. In the last picture, I tried to show how the wires are attached to the receptacle (also as I described above.)

I'm confident I wired this exactly how it was before. And, as I mentioned, it works perfectly.

But both parts of the receptacle are indeed shut off by the same circuit breaker, leading me to believe they're part of the same circuit. But honestly, it looks to the novice almost as if both halves are end-of-runs.

Anyway, please let me know if any other information would be helpful and I'll try to clarify or research further. Thanks much!
 
  #18  
Old 07-17-07, 04:00 PM
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You should remove the wires from the back stabs and use the screw terminals. Back stabs tend to fail over time and are an unreliable connection. Those who know better never use back stab connections. You will eventually regret it.
 
  #19  
Old 07-17-07, 04:27 PM
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These aren't backstabs, they're commercial-grade "back wire" connections, held in place by screws (see the long discussion above.)

The specific question I'm asking is about whether the neutral tab should have been removed by the original installer of the receptacle.
 
  #20  
Old 07-17-07, 04:48 PM
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The answer is, of course yes. Whether or not it should have been wired this way is another question. But two separate hot wires from two different cables means two separate neutral wires are required.
 
  #21  
Old 07-17-07, 04:54 PM
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If they are indeed on the same circuit, then it makes no difference whether you break off the neutral tab or not. But we should clarify exactly what "same circuit" means. It means that a simple single-handle breaker turns off both. By "simple single-handle", I rule out any kind of double-pole or tandem breaker which might actually be two handles tied together.

Earlier when you were talking about how much wire to strip, I would note that you should not pinch any of the insulation under the pressure plate. Better to have a small amount of bare wire outside the pressure plate than a small amount of insulation under it.
 
  #22  
Old 07-17-07, 04:58 PM
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Thanks for the replies; it is indeed a simple, single-handle 15 amp breaker.

Sounds like I should leave it the way it is then (with both tabs broken). Why might someone have wired a run of outlets this way?
 
  #23  
Old 07-17-07, 05:05 PM
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John, I disagree. If you leave the neutral tab intact then the neutral current will be split across two neutral wires in separate cables while the hot current will be on only one cable.

We have no idea where those cables go, so we don't know if they go to separate boxes, the same boxes, metal boxes, etc.
 
  #24  
Old 07-17-07, 05:15 PM
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Bob, you have a good point. 99% of the time it would make no difference. But breaking off the neutral tab would cater to that other 1%. So there's no good reason not to break it off, and there might be a good reason to do so.
 
  #25  
Old 07-17-07, 06:05 PM
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The 2005 NEC in 300.3 (B) requires all wires in a circuit to be in the same conduit or cable absent exceptions that wouldn't normally apply in residential wiring. If the circuit is divided by a switched leg it may either share the neutral in a 3 or 4 conductor cable (14-3 or 14-4) or another neutral can be run in another cable with the associated hot wire. This second method would require both tabs be broken to prevent parallel neutrals to the device if both circuits supply the same device.

This same reasoning applies to bathroom fans with lights and/or heaters. Unless each part of the unit has a separate neutral that can be connected to a separate cable for each function, the wire must all be in the same cable as the common neutral.
 
  #26  
Old 07-18-07, 04:59 AM
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As for why this was done...

There are several reason why this might have been done.

The receptacle may have originally been completely switched, and the decision was made to change it to be only half switched. Rather than change the cable to be 14-3, a piece of 14-2 was added.

The receptacle may have originally been not switched, and the decision was made to change it to be half switched. Rather than change the cable to be 14-3, a piece of 14-2 was added.

Wiring may have been done by someone who did have and did not want to buy 14-3; they may not have known they could abandon the old cable in the wall; etc.

To speculate further, you could find out where those cables go.
 
  #27  
Old 07-18-07, 09:21 AM
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Except in those few areas requiring conduit, most home are wired with NM-B cable and non-metallic boxes. In that case, the exceptions in 300.3(B) would apply.
 
  #28  
Old 07-21-07, 05:07 PM
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I'm continuing on this project and today I've encountered two problems.

First, there's a receptacle which now reads "open ground" after replaced on the 3-prong tester. It's an end-of-run receptacle with literally only three wires coming into the box. I tried replacing the receptacle, relooping the ground, etc., but no dice.

So my next thought was to look at the previous receptacle in the run and see if perhaps the ground had come loose from a wire nut.

Interestingly, the previous receptacle in the circuit had been replaced by a professional electrician two weeks ago. I hired him to do some more major work and also had him replace a few receptacles so that I could learn first-hand more about how it was done.

When I pulled the receptacle apart, I noticed on the back of the receptacle what looked like melted copper. The wires (two in each side--he didn't pigtail) seemed securely in the backwire, but it looks to me like there's a bit of burn residue on the back of the receptacle. Also, one of the hot wires looks a little singed. There has been no load on this part of the circuit other than my 3-prong tester over the last few weeks.

I put up a picture here for you to look at:

http://headworld.net/pictures/problem.jpg

Am I analyzing this situation correctly? What could have caused this?

Again, when I looked at the receptacle, it seemed as if the wires were fully inserted. Unfortunately, I didn't notice this until I already unscrewed the screw, so I can't vouch for how tightly they were screwed down.

Could this be just under-tightened screws? Should I just replace the receptacle and not worry about it?
 
  #29  
Old 07-21-07, 06:02 PM
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Maybe it's my older eyes, but I do not see burn residue.

As for your problem, follow the ground back. There should be two ground wires at the receptacle before the last one, and they should be connected with a wire nut and pigtailed to the receptacle and to the metal box.

This should be the case at each receptacle down the line. Use your tester and verify each receptacle until you find the problem.
 
  #30  
Old 07-21-07, 06:34 PM
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racraft, thanks for the reply!

I drew a red box around the portion of the receptacle that looks problematic to me. It looks something like melted copper.

Hopefully this updated picture makes it more clear what I'm talking about:

http://headworld.net/pictures/problembox.jpg

(It's just inside of the top screw hole on the hot side.)
 
  #31  
Old 07-21-07, 06:52 PM
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While I do not know what that is, it's nothing to be worried about.
 
  #32  
Old 07-21-07, 06:58 PM
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Glad to hear you don't think it's anything too major. It almost looks like an in-receptacle arc (the end of the hot wire was a little darkened--surprising since it was newly stripped two weeks ago.)

Anyway, I replaced the receptacle (to be on the safe side), retwisted the grounds and wire nutted them together with a new wire nut, and pigtailed the rest of the wires so that there's only one hot and one neutral going to the receptacle.

All is well and the open ground is fixed. My thought is that when the electrician replaced the receptacle he jostled the wires in such a way that one of them came loose from the grounding nut.
 
  #33  
Old 07-21-07, 08:26 PM
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That explanation makes sense.

Note that while using pigtails on a receptacle for connecting two wires is allowed (and some would say preferred), it is not necessary, especially with back wire type receptacles, that are designed to take two wires per plate. But, it's your house and as long as it's legal and safe, do whatever you want.
 
  #34  
Old 07-21-07, 11:14 PM
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Thanks for the advice!

I've been doing the pigtails just because as long as I'm doing it, I'd rather take the time to do them the best way. (Or at least, the way I feel best about it.)

Another thing I've noticed is that it is a bit easier to get the receptacle to mount flush (not tilted one way or another) when there's only the three wires coming into it, not a whole tangle of wires pressed into all of the holes.

I started off doing them that way (in case using all 8 holes!) but have since learned that I much prefer pigtailing.
 
  #35  
Old 07-22-07, 10:58 PM
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The surprises keep coming.

Tonight I was working through a bedroom and there's a peculiar stretch of wall in which there are two receptacles directly next to one another. Literally, this is the only place in the house with this kind of non-standard spacing. (This is a fairly new house: 1999.)

Here's a picture:

http://www.headworld.net/pictures/weirdwire1.jpg

The two receptacles are on different circuits as well... the one on the left (which I've already finished replacing) is on the same circuit as the rest of the bedroom. The one which is open in the picture above is on a circuit with lights and receptacles in the hall outside of the bedroom.

I opened up this mysterious extra receptacle and, to my surprise, found a strange cable in there in addition to the electrical cable. It's actually four wires wrapped up in a single cable: black, red, yellow, and green. They're much smaller than #14 gauge... maybe #18 or so?

A picture of the mysterious cable is here:

http://www.headworld.net/pictures/weirdwire2.jpg

The cable was just loose in the box, not connected to anything.

So my questions are:

1) Do you have any idea what this cable is and what it might be for?

2) Is it safe to leave it just sitting in the box? Is there something I should do to terminate it?

Thank you!
 
  #36  
Old 07-22-07, 11:20 PM
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I might guess a previous owner was also running some low-voltage out the same box for maybe a cheap home theater or something? Do you have speaker holes in the ceiling or other signs of something like that?

I would see no danger in taping it off and leaving it the box. Or, since it shouldn't be there anyway, try pulling it out or cutting it short and taping it off, and maybe pushing back to abandon in the wall.
 
  #37  
Old 07-26-07, 10:13 PM
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Light switch question...

I've replaced about 40 receptacles so far, but I'm on only about my 5th light switch.

I encountered a switch tonight which actually had 4 black wires coming into it (not the usual 2): one on each screw terminal, and one in each backstab.

I am replacing the switch and don't want to use the backstabs in the new switch... so is it OK if I pigtail the connections (like I might on a receptacle?)

What I'm planning on doing:

1) Nut the two wires formerly attached to the top screw & top backstab together with a pigtail and attach the pigtail to the top screw terminal of the new switch.

2) Nut the two wires formerly attached to the bottom screw & bottom backstab together with a pigtail and attach the pigtail to the bottom screw terminal of the new switch.

This seems to make sense to me, but I wanted to double-check with you guys in case I'm missing something. Thank you!
 
  #38  
Old 07-27-07, 04:11 AM
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This is correct. Pigtail as you have indicated. Or use a back wire switch and connect both wires to the back wire connection.
 
  #39  
Old 07-28-07, 05:11 PM
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Now I'm up to replacing a couple of GFCI's.

I was reading through the instructions for the Leviton GFCI I purchased, and it says "if there are more than 4 wires coming into the box, not counting grounds, contact a licensed electrician."

Well, this GFCI as previously wired has 8 wires: two each hot line, hot load, neutral line, and neutral load. The GFCI was backwire with two ports per screw for a total of 8 (all used by the previous wiring.)

I carefully noted which wires were which and wired the new GFCI exactly the same as the old one. I powered it on and it works perfectly, as do downstream receptacles.

So my question is: why the admonition to contact an electrician if there are more than 4 wires in the box? Is there some added complexity here that I'm not understanding?
 
  #40  
Old 07-28-07, 05:47 PM
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They just didn't want to bother to try to write up instructions for every conceivable configuration of wires. Since you had an old GFCI that you could just duplicate the wiring from, there's no issue.
 
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