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Old 11-23-2009, 06:17 PM   #1
 
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Continuity between neutral and hot with breaker off?


I replaced all of the outlets in a room with new ones, and with the exception of one outlet and one switch that were against code (two wires on one screw - replaced with pigtail), rewired them exactly the same as the previous outlets. As soon as I went to turn the breaker on it tripped on me right away - meaning I screwed up somewhere. The two suspects were the switch and outlet I rewired, and after testing the outlet (and wires) with a multimeter, I've got continuity between neutral and hot when the breaker's off. I'm pretty sure I shouldn't be having that, but I wanted to check with more knowledgeable people. The next trick is how can I figure out where that's happening? The outlet worked perfectly fine before I put the pigtails in and I've made sure they're not touching in any way.

Ideas?
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Old 11-23-2009, 06:25 PM   #2
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You will have continuity if there is a light on or appliance plugged in on that circuit.


Is there a ceiling light in the room?

My guess is that you created a dead short at a 1/2 switch receptacle. It happens often. Look at the receps you removed. On the hot (brass colored) side, is the "tab" between the two screws broken off on of them?

To find the recep that was half switched, pull the switch and see if there is only a black and a white wire going to the switch. If so, remove all receps and check continuity on each pair of wires when you flip the switch on/off.

Last edited by 220/221; 11-23-2009 at 06:29 PM.
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Old 11-23-2009, 06:48 PM   #3
 
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Nope, there are no 1/2 switched receptacles, I checked that before I took out the old outlets, just in case. The light/fan switches are all switched off (one in a closet and one ceiling light/fan) and on the one breaker. One of the receptacles (the one initially wired wrong) has a switch to the ceiling light/fan added to it further up the wall (it was a shoddy job, and I doubt an electrician actually did it). I could see how there'd be continuity there if the switch wasn't off, but as the switch is working (it was replaced about a year ago), I'm guessing there shouldn't be continuity.

Any other troubleshooting tips to try since I can't run current? My best guess was that somewhere I was touching ground to the hot, but all of the outlets test OK, and I've double checked that no wires are touching. I know it's something I did, I just can't figure out what
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Old 11-23-2009, 06:54 PM   #4
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Quote:
Originally Posted by elwing View Post
I can't run current?
You can run current, through a current limiter.

After confirming there is no voltage with respect to ground, put 120v in series with a 100w incand. bulb in series with the short.
Measure the voltage across the short. The voltage measuring leads should not touch the leads that pass the current.
0.1v at 0.83A [current drawn by the bulb] = 120 milliohms = a 75' loop of #14 copper. For smaller loop lengths use a 10A hair dryer to limit the current.

Last edited by Yoyizit; 11-23-2009 at 06:58 PM.
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Old 11-23-2009, 06:58 PM   #5
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OK, you have a circuit...

Breaker, outlet A, outlet B, outlet C, outlet D, outlet E, and outlet F.

And black and white wires going from outlet to outlet.

A good troubleshooting trick is to disconnect the wiring in the middle and see which direction the short is going...

So disconnect the wires going to outlet C and test the wires going both directions.
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Old 11-23-2009, 07:17 PM   #6
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Quote:
I'm guessing there shouldn't be continuity.
What about the rest of the circuit in the other rooms?

You say the fan/light was added. Was there a ceiling light originally?

Too many questions to do over the internet. This would take 5 minutes in person.

Start from scratch. Take the receps out and unwire them.
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Old 11-23-2009, 07:59 PM   #7
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Could be a ground wire touching a hot when receptacles pushed back in box. Could be a receptacle touching side of box if mis installed in box.
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Old 11-23-2009, 08:28 PM   #8
 
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Found a half-switched outlet - with no switch - no wonder I thought there wasn't one. Broke the tab and it's sort of fixed, and I can turn the breaker on now, but despite how I try to wire it, I keep getting hot/grd reverse on the switched part, and all of the outlets after that receptacle (and lights in the circuit won't turn on - I'm thinking I might have blown them). Right now, all hots are pigtailed together to the "top", and the neutrals are connected to the other screws (and ground to the appropriate one).

Working on figuring out how to wire that receptacle up right, but haven't asked google yet. Thanks to everyone who replied!

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Old 11-23-2009, 09:29 PM   #9
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What do you mean by a half switched outlet and no switch? Is there a cable daisy chaining off the other half and you don't know where that cable goes? Perhaps to a switch somewhere?

Can you take a picture of that "hafl switched" outlet and post it?
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Old 11-23-2009, 09:33 PM   #10
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Sounds like you had a split wired receptacle. Is there a black and a red wire connected to receptacle? How many breakers are involved?

You should only split the gold side not the silver side. Hot ground reversed is usually an open neutral.
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Old 11-23-2009, 09:47 PM   #11
 
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Allan J - There's a switch loop in the receptacle box, but there's no corresponding switch. There were also four wires going to the outlet (two white, two black), which is why it didn't register with me that it was half switched. My guess is that in the past, someone decided that they didn't want that outlet switched and removed the switch - and closed up the box with drywall (I have a suspicion as to where it is, but I'm not about to punch holes in my newly painted drywall to find out). There are now three white wires (one marked "hot" with black electrical tape), and figuring out which was the correct "hot" white wire was what was causing my open neutral. Everything's wired up so that it's working. Thanks to Billy_Bob who made me think to look at the "middle" outlet - which is where the problem was, and everyone else for making me think about what was going on and figure it out.

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Old 11-24-2009, 07:14 AM   #12
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Both of the switch loop wires (white with black tape and the black wire from the same cable) should not be connected to anything, have their ends taped individually, and curled up in the box out of the way.

They may be used by the next homeowner after he finds the switch box and chips the wall open to install a switch or possibly something else.
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Old 11-24-2009, 05:58 PM   #13
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Quote:
Found a half-switched outlet -



Disconnect switch loop, both black and white. Leave them capped off in the back of the box.

Hook up the other blacks and whites without breaking the tab.
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