Son bought a house that is several years old and is updating outside light fixtures. On the far side of the house is a GFCI that has no power. On a brick column near it is a light fixture that I was going to change. Using a voltage detector I found no voltage. I removed the fixture and in the process 2 wires touched and arced. Testing again the wires showed no voltage. I replaced the fixture and then checked the breakers. None tripped. I checked all the receptacles on that side of the house and found that they all worked. Checked every GFCI in the house and they all worked. Checked all switches and they work on all fixtures. I am unable to find the power source for the GFCi and fixture. Any idea on finding the power source. The brick column was added by the previous owner. Unable to find any buried wiring coming from brick column because concrete was poured around it. My next step is to pull cover plates on receptacles on that side of the house to check to see if additional connections are added but I would think that the light should have a switch. I can understand that the GFCI may be wired to the in house receptacle on the opposite of the wall.I have thought of turning all breakers off except one and using that breaker to back feed the light fixture to see if it returned power to a breaker that has no power. Any ideas?

I'd start w/ getting a new voltage detector,...could have kilt you !!

Buy a Circuit Tracer. Put a Socket to Outlet Adaptor in the light socket. Plug in the tester's transmitter. Take the detector to the breaker box and it will show you EXACTLY which breaker is powering that circuit. I use mine all the time.And I second RJsfishin's suggestion.

It is likely a previous owner had problems with the GFCI and simply bypassed it. Thats why you had hot wires outside at the light.

I'd say you either need a new voltage detector, or a new operator. Something is not right. Even when not hot, you never let 2 wires touch each other, put a twist cap on on all the hot wires, neutral too, when working on them.

Identify power source-UPDATE | Good Sam Community

Bobbo
Explorer II
Dec 31, 2014
Glad it worked for you. Thanks for the followup. This may help someone else in the future.
Charlie_D_
Explorer
Dec 31, 2014
Bobbo_Bought the tone generator and it worked great. Has a very strong tone anywhere on the property. Found the power source as a switch outside his back porch that has a cover over it. That switch had another switch in the same box that supplied power to his pool light. Both were protected by GFCI.
Bobbo
Explorer II
Nov 09, 2014
If this suggestion doesn't work, I am out of ideas.

Sometimes, when a breaker trips, it doesn't LOOK like it tripped. Did you try turning every breaker completely off then back on? If a breaker tripped without a visual appearance, that would reset it and put power back to the light fixture.

Personally, I don't like back feeding a circuit. But if you only do it for testing purposes, it should be harmless. I definitely don't like backfeeding one and leaving it live, but that is not what you are comtemplating.

Here is a Tone Generator. It does not require a circuit to be live, like the circuit tracer I mentioned earler. You hook the clips to the wires and activate the tone generator. The tracer then lets you follow/find the wires at least up until the break in the line. It may be safer than backfeeding the circuit. I have a tone tracer, but have never had a need to use it so I can't give any personal feedback on how useful it really is.
Charlie_D_
Explorer
Nov 08, 2014
Bobbo-No power to the GFCI prior to the arc at the lamp fixture. Checked it before opening the fixture up. When I found no power at the fixture-same fixture that my voltage detector incorrectly said was no live-my first thought was a tripped GFCI.

I did pull the GFCI from the box and there is only 3 wires to it so it does not feed anything. Been busy the last few days but will check the receptacle directly behind the GFCI on the inside wall to see it it was/is hooked to the GFCI. It would make sense that it would be.

My original question to all was my idea to turn all breakers off except one. Run a live wire from the breaker to the light fixture and see if any receptacle or switch became live. If it does I should be able to back track the feed location. As I said earlier, all breakers are on and none tripped. No GFCI's are tripped. Every switch in the house has been flipped on and off and never any feed to the light fixture.
Bobbo
Explorer II
Nov 08, 2014
Did the GFI outlet have power BEFORE the light fixture arced? If so, maybe the GFI outlet feeds the light fixture, and the arc destroyed the GFI outlet. The only way to check is to take the GFI outlet out and see what is in that box. Be careful, because there may be hot wires behind the outlet, even if the outlet, itself, is dead.

Come to think of it, that would be a very useful piece of knowledge, even if the GFI was dead before the arc. My next step would be to take that outlet out and see what is going on in that box. It is very possible you have power TO that box, but no power out of it.
Charlie_D_
Explorer
Nov 07, 2014
Bobbo-The wires did arc and then there was no power to the light fixture. Also have a GFCI located on the outside wall near the fixture is no power to it. Tried to trip it but won't trip or reset without power.
Bobbo
Explorer II
Nov 07, 2014
Charlie D. wrote:
Bobbo wrote:
Buy a Circuit Tracer. Put a Socket to Outlet Adaptor in the light socket. Plug in the tester's transmitter. Take the detector to the breaker box and it will show you EXACTLY which breaker is powering that circuit. I use mine all the time.

And I second RJsfishin's suggestion.

That only works with a powered circuit. The GFCI and light does not have power.

My mistake. You said the wires arced when you touched them. I took that to mean it had power since power is required to create an arc.
Charlie_D_
Explorer
Nov 07, 2014
Niner-Has a sub panel dedicated to a hot tub. 240 V with one Ground Fault breaker to hot tub and another breaker in same panel dedicated to the clock timer for the pool and Polarus vacuum. They work fine.

fcooper-Same as one posted by bobbo-requires power at breaker and receptacle/light. to work. Do not have power to light.

Neighbor is a master electrician and co-worker of a residential and industrial business. Will ask him when he is available.
NinerBikes
Explorer
Nov 07, 2014
Any sub panels on the property?
fcooper
Explorer
Nov 07, 2014
Charlie D. wrote:
....text deleted....

7)WA8XYM-Got a better description? Can not find item you describe.

The Harbor Freight item that WA8YXM referenced can be found by searching on their web site for "circuit breaker tracer".

Fred

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