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Some lights and outlets started going out intermittently in my home. Circuit breaker did not trip off but under inspection with a multi-meter, produced no voltage. I disconnected the load from the breaker (Disconnected the black wire from it) and checked again with the multi-meter. It produced 117 volts. I installed a new breaker and same deal - under load; 0 volts - disconnected from load; 117 volts. Neither breaker tripped. This circuit has worked for years without fault.
Recent work on home - the roof leaked through the ceiling a few months ago and we replace the ceiling. Could a drywall screw through a wire cause this issue? Any assist is appreciated.

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also check the amps going through, one leg to the breaker and the other to the black wire –  ratchet freak Mar 11 at 9:29
    
First reaction sounds like a cross feed of source voltage from another circuit. Try turning off breakers, one at a time until the voltage goes to 0. There is a starting point to help troubleshoot. –  shirlock homes Mar 11 at 10:05
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Where are you measuring from? You have one probe on the terminal screw of the breaker, where is the other one? –  Tester101 Mar 11 at 10:18

3 Answers 3

You might have a break in a wire, a loose connection, or corrosion. See http://diy.stackexchange.com/a/27285/82

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Sounds serious.

The presence of line voltage (117V) on the wire indicates a possible cross connection between two circuits. If you put an circuit tester between the disconnected black and your panel neutral, and it glows, you've got trouble. As @shirlock homes says above, turn off breakers one by one until that voltage goes away.

A drywall screw through an otherwise unchanged circuit would not produce the results you describe.

You can repeat the experiment with the breaker on and off: it should produce the same results as removing the wire.

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Also, check the neutrals. If some how a neutral got disconnected then you may have created a 208v circuit which requires both breakers on and two loads plugged in. Sometimes this situation, when engineered intentionally, is called 'floating neutral'.

Gotta check the neutral. Its a savior.

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Thanks friends. I'll try some tests based on your information and report back. –  Doug Mar 12 at 9:20

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