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Mike, Master Electrician
Category: Electrical
Satisfied Customers: 1425
Experience:  Licensed Master Electrician - OnQ Certified Data Voice Audio Video Installer
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I have a detatched garage. I started my small air compressor

Customer Question

I have a detatched garage. I started my small air compressor and the power was cut off, as if the circuit breaker had tripped. It hadn't, but I was still without power. The garage is on a 20 amp breaker with 2 romex cables entering the garage via an underground conduit. I replaced the breaker having had a spare, with no change. There is a gfci outlet upstream of 2 other outlets and a light switch which I also replaced, having a spare. Still no change. There is an outside wall light on the garage, controlled by two 3 way switches, one in the garage and one in the house, and that DOES work. Where the 2 lines enter the garage there's a junction box with 4 wire nuts connecting the hot and neutrals, and one connecting the grounds. Using a common outlet tester with the orange led light, when testing between the hot and neutral (black and white) connections, only one neutral connection failed to light the test light. I've also redone all the connections downstream of the house panel, and those within it that I can access. The load line in the garage passes through a triple switch box, and I've replaced the two simple switches but not the 3 way (didn't have a spare handy). I'm stumped. Help!
Submitted: 2 years ago.
Category: Electrical
Expert:  Mike G. replied 2 years ago.
Hi, I'm Mike and I'll be glad to assist you. What isn't working besides the compressor outlet.
Customer: replied 2 years ago.
The only thing that does work in the garage is the outside light controlled by two 3way switches. There's also an outside mercury vapor light, two inside light switches/fixtures, two standard dual outlets and one GFCI outlet upstream of the other two outlets and one light.
Expert:  Mike G. replied 2 years ago.
With a 2 wire voltage tester, you need to test the first junction ahead of the non working items. We need to know which wire is open. Test hot to neutral,hot to ground, neutral to ground for voltage. Then test neutral to ground for continuity. Let me know the results.
Customer: replied 2 years ago.
I already have done all that and tried to describe it in my initial inquiry. Where the power enters the garage from an underground conduit is a junction box that has two romex cables connected by five wire nuts (one for grounds, two each of the neutral and hot wires). I get no continuity from only one of the neutral(white) wire nut connections. I'm assuming this is the line that feeds the bulk of the garage loads, all of them but the outside light (on the two 3 way switches, one in the garage on a triple switch panel, and one in the house).
Customer: replied 2 years ago.
Anywhere downstream of this junction box has no power, other than the outside light and the 3 way switch.
Customer: replied 2 years ago.
I wish I had a Fluke (and knew how to properly use it!).
Customer: replied 2 years ago.
My apologies!
I hadn't checked the continuity to the ground yet. If I number the connections 1-4, odd #s being neutrals, evens hot, 1to 2 is good, 2 to 3 (and ground) is good, 4 connects to nothing.
Customer: replied 2 years ago.
(Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Mike G. replied 2 years ago.
I'll make arrangements for the phone. Stand by.
Customer: replied 2 years ago.
"I'll make arrangements for the phone. Stand by."
That didn't happen, and you don't need to bother. I fixed the problem without your help, fortunately. Honestly, you started off asking for details I'd already provided. I have a better than average understanding of most household systems, but I'm no expert. I'd hoped for more input from one, however.

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