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Source wires must be connected to load to read voltage - Help T/S

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sjorlin

New User
Location
Simpsonville, SC
Occupation
Engineer
This issue has me going crazy, maybe someone can help me out. I have four duplex receptacles in my garage fed from a single breaker in the main panel. Two of these are in the ceiling and are in dedicated use, one for each garage door opener. The other two are in the back wall, and one of those is a GFCI. I have confirmed that the GFCI receptacle does feed the other non-GFCI in the wall, but NOT the ceiling receptacles. So it must be fed from one of them.

Now the issue. I disconnected one of the ceiling receptacles (closest one to the panel) to remove it because I want to branch off from this one to add a new receptacle for a wall-mount opener I am adding about 10 feet away. This receptacle has two hot and two neutral wires connected to it. I first turned the breaker off, then disconnected one hot and one neutral (from the same cable of course). Then I turned the breaker back on, and proceeded to measure voltage across the disconnected wires and then across the connected wires. To my surprise, no voltage on either, and the three other receptacles (one ceiling, two wall) were both dead! I was trying to determine which cable was the power source, but couldn't.

After many other checks, and with the receptacle now completely disconnected and removed, I connected both hots together with a wire nut, and both neutrals with a wire nut. Flipped the breaker back on, and the other three receptacles now all have power.

I can't think of any explanation of why I can't measure voltage across either hot-neutral pair going to this first receptacle box with the circuit breaker on, but can when they are connected together. Does anyone have any ideas? I am not an electrician but I have wired a complete panel and subpanel previously, so this is not my first time doing this or using my multimeter. I am using a Fluke 336 amp clamp set to AC voltage, and tested it across other uncovered receptacles to make sure it is working.
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician
I am closing this thread in accordance with forum rules. If you are not an electrician, we are not permitted to assist you in performing your own electrical installation or maintenance work.

If installing stuff is not your occupation, then we can’t help you install stuff. You would have had to agree with that rule during the process of registering on the forum.

The reason is that the forum’s owner does not want a person to get an answer to the question they asked, but not get answers to the dozens of other questions they should have asked and were unaware they needed to ask. An engineer is less of a risk in that category, still Mike doesn’t want anyone to get injured by any incidents related to electrical installations.
 
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