Receptacles: low voltage troubleshooting

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Old 06-07-15, 01:21 PM
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Receptacles: low voltage troubleshooting

I have a little outbuilding next to the house I want to fix up, and the lights & wall plugs stopped working at some point. There is a motion sensitive light above the front door that does work. I tested it with a multi-meter and it shows 120 or so. When I test the wall plugs, they give me readings around 25. The "attic" is filled with nasty insulation and mouse droppings, and various junction boxes.

The motion light is wired back to one of the junction boxes in the attic. Strange that it's the only thing that works.

Another strange thing. I found the circuit breaker on the panel in the house for the motion light. I turned it off, but the wall plugs still show 25 when I test them.

I am an electrical noob, so please use simple words & short sentences !!
 
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Old 06-07-15, 03:01 PM
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Welcome to the forums.

You haven't given us much to work with.
You'll need to determine if there are one or two circuits feeding that building.

If it's only one then you need to check the splices that incorporate the front door light.

You're going to have to be a Sherlock Holmes and investigate.
We can't help you with what we can't see.
 
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Old 06-07-15, 03:12 PM
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What are some possible, general causes of low voltage at an outlet ??

I will do some more crawling around and see what I can figure out.
 
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Old 06-07-15, 04:10 PM
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A loose wire or connection. Check for voltage from hot to ground as well as hot to neutral. Report back.
 
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Old 06-07-15, 04:14 PM
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Another strange thing. I found the circuit breaker on the panel in the house for the motion light. I turned it off, but the wall plugs still show 25 when I test them.
There can be only one circuit to the detached building if it has no subpanel. There might be a code loophole to allow the light on the outside to be powered by a second cable from the house if so that means it isn't relevant to your problem.

Lets start with the basics. Does the shed have a subpanel? How does power get to the shed?
 
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Old 06-07-15, 04:56 PM
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Another strange thing. I found the circuit breaker on the panel in the house for the motion light. I turned it off, but the wall plugs still show 25 when I test them.
Are you using a digital meter? Sounds to me like phantom voltage
 
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Old 06-07-15, 06:30 PM
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Yes, digital meter, set to 200. I get 120 in the house outlets and at the outside light of the "cottage".
I will try to do some more "detectiving".
 

Last edited by homebrew01; 06-07-15 at 07:13 PM.
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Old 06-07-15, 07:04 PM
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Please tell us how power gets to the shed. We are stalled out till you tell us that. Is that the detective work?
I get 120 in the house outlets at the outside light of the "cottage".
Doesn't prove anything really. A cheap digital that works correctly can still easily be fooled by phantom voltage. That's why we recommend a cheap analog multimeter.
 
 

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