Half voltage on neutral, sometimes

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  #1  
Old 09-18-13, 10:39 PM
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Half voltage on neutral, sometimes

I have been replacing old duplex outlets with new ones. After working on one 20A circuit in the living room, none of the outlets work. After investigating, I have disconnected all outlets except the first one from the panel (wires out and not connected to anything). When nothing is plugged into the plugs, I have 120v hot to ground, 0.5v hot to neutral, and 0.1v neutral to ground. I us a no touch tester and it shows the same thing, just the hot is hot.

I then plug in anything (lamp, cell phone charger, outlet tester) and the voltages change. The outlet tester has all three lights on. The Lamps don't work. Hot to ground is 120v, hot to neutral is 70v, and neutral to ground is 60v.

When taking the old outlets out, one of them had the neutral and ground pigtailed together, which seemed odd and I have not done.

I'm stumped here. Any help with the cause and the solution is greatly appreciated. TIA.
 
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Old 09-18-13, 10:50 PM
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Welcome to the forums!

Remove all devices and test directly on the wires. Use an inexpensive analog multimeter, or a digital one that adds a small load to override induced voltage. Use your squawk stick only to determine whether you have the power on or off.

It sounds like you have an open neutral between the panel and the first outlet (box). You should be reading 120V hot-to neutral, 120V hot-to-ground and 0V neutral-to-ground.

one of them had the neutral and ground pigtailed together, which seemed odd and I have not done
I suspect someone did that to bootleg a neutral. It's a good job, and a close thing, that this hasn't caused a fire.

You need to trace the wiring from the first device location back toward the panel until you find and repair the open neutral. A tone generator can be a big help with that.
 
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Old 09-18-13, 10:58 PM
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Welcome to the forums.

one of them had the neutral and ground pigtailed together, which seemed odd and I have not done.
You've lost the neutral to your circuit. That I'm almost 100% sure of.

You've been changing out old duplex "receptacles".
1) Where there grounded ones in there that you are replacing ?
2) Where there any two slot non grounded type receptacles in the house ?

If your house was wired in old style two wire cable with no ground then there would be no ground at each box. Many people erroneously thought that since the neutral and ground were connected together at the panel......they could just tie the ground from the receptacle to the neutral and all would be ok. That is a disastrous mistake. Never tie the neutral and ground together.

There is another thing I've seen done that is more of a disaster. The neutral in the circuit was lost so they tied the neutral wire to ground so the the ground would replace the neutral. Another disastrous wiring method.

You need to back up and find out where you lost the neutral. There may be other receptacles that are working on that circuit.....the problem can be in one of those.

stereo.....................
 
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Old 09-19-13, 06:59 AM
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Thanks for the welcome and the help!

All other receptacles have been grounded and there are no 2 hole receptacles.

It looks like I need to trace back the neutral and see where it is open.
 
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Old 09-19-13, 09:01 AM
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All other receptacles have been grounded and there are no 2 hole receptacles.
So your house is wired with 3-wire cable and has a ground wire in each box? If so, carry on.

It looks like I need to trace back the neutral and see where it is open.
Yes. An open neutral can create hazardous voltage conditions. See Troubleshooting a dead receptacle or light,...
 
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Old 09-19-13, 09:22 AM
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One thing i don't understand is why the 3-light outlet circuit tester showed all three lights on for an open neutral, instead of the the one light that specifically designates and open neutral...
 
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Old 09-19-13, 09:34 AM
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One thing i don't understand is why the 3-light outlet circuit tester showed all three lights on for an open neutral, instead of the the one light that specifically designates and open neutral...
Those testers are almost useless and can be easily fooled. Your tester was fooled by the neutral being attached to ground.
 
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