Help needed from the TGO electrician brain trust...

[G27]

We just recently lost power to an entire circuit of outlets (seven outlets, no lights) in our five year old house. I found the last one in the chain and disconnected them one by one tracing the circuit back via an external wire and the continuity setting on my DMM - there are six standard outlets with a GFCI outlet being the first (as far back as I can trace it, that is) in the circuit. After the GFCI I have no idea where the circuit may go, I assume back to the breaker panel as every other outlet, light, etc is accounted for on other circuits.

Unfortunately, the GFCI is at the front door entry way, so it is surrounded on three sides by brick and the the fourth side abuts the front door, so getting to the wiring behind the box to trace it is nearly impossible. At this point, I think there's an open in the wiring between the breaker (which is new and tests fine) and the GFCI outlet (which is also new). What do you, as electricians, do to find an open to repair such an event? Is there some sort of tracing rig that will work on a non-energized (open) circuit to help trace the wire in the wall?

Any help appreciated, thanks in advance...

[Raoul]

The obvious first question, did you reset the GFCI?

[Farman]

May seem silly, did you reset the GFCI, check the circuit breaker. Is there power to the line side of the GFCI outlet? Circuit breakers and GFCI do go bad more often than a wire breaking.

[titan14]

I have also seen SEVERAL GFCI's bad, right out of the box.

[mikegideon]

A broken wire is real unlikely. About the only problems I've ever seen with wire has been electricians that created shorts because of sloppy cable prep. The GFCI outlets in my house are wired to protect everything on the circuit, so if the circuit goes down, it's always a GFCI trip.

If it is a broken wire somewhere, you can do your continuity checks with a long extension cord. Kill power on the circuit, plug the cord into the outlet in question, and drag the other end to where you want to make your check.

[DWARREN123]

GFCI tripped or wired wrong?

[G27]

Replaced both the GFCI and the breaker to be sure, no go. Did just find that the disposal and dishwasher are on the same circuit and are working fine. Now I have to try to pull the outlet from underneath the sink to see if something has come loose...

[G27]

Hrmm, very strange - when the breaker is turned off, I'm still getting a 40vac reading on the line on my DMM (when it's on, I get the full 120vac).

[mikegideon]

Hrmm, very strange - when the breaker is turned off, I'm still getting a 40vac reading on the line on my DMM (when it's on, I get the full 120vac).

That's a little scary. Are you sure it's 40 volts? You could easily pick up 40 millivolts of stray on an auto ranging meter.

[Photoguy67]

I have a fluke and regularly get stray readings like that. I think its the current load on the neutral line but I am NO expert.

[mikegideon]

The neutral (white) is always connected to the neutral buss in the panel. The hot (black) runs thru the breaker. The ground (bare), is connected to the ground buss in the panel. The neutral and ground busses are connected together in the panel. In most cases, they're the same buss (shared).

[G27]

Turns out I was mistakenly reading the diff between a hot leg and a switched leg (for the disposal).

I know just enough about electricity to bring down the entire east coast...

[safeandsecure]

Is there some sort of tracing rig that will work on a non-energized (open) circuit to help trace the wire in the wall?

I'm no electrician, but there is a product that generates a tone, readable by a second instrument. Sold in a package with both "sender" and "receiver." Should be able to trace the tone from wherever you place the tone generator all the way back to the box. Seems that Home Depot or Lowes used to carry one or two brands of these. Sorry, but I can't remember the name. I've used one a couple times to trace telephone and security wiring when I was helping a bud do some work. It was old (or at least looked old), so I can't vouch that they are still available.

Edit: Both parts required batteries for power, so they worked with no line voltage.

[Guest bkelm18]

I'm no electrician, but there is a product that generates a tone, readable by a second instrument. Sold in a package with both "sender" and "receiver." Should be able to trace the tone from wherever you place the tone generator all the way back to the box. Seems that Home Depot or Lowes used to carry one or two brands of these. Sorry, but I can't remember the name. I've used one a couple times to trace telephone and security wiring when I was helping a bud do some work. It was old (or at least looked old), so I can't vouch that they are still available.

Edit: Both parts required batteries for power, so they worked with no line voltage.

Circuit tracers/breaker finders are great little tools. However, I'm not sure how well they work through walls. Well, since the GFI and the breaker aren't the cause, and you say certain things on the circuit are working while others do not, that definitely points to a loose broken connection somewhere. Lines don't "just break". Unless you have rodent issues then I'd be willing to bet that the line is fine. Check around for loose connections, including the neutrals in the breaker box. Corrosion can also lead to these types of things though I rarely see that indoors. Another nifty little tool is an outlet tester. They cost less than $5 at the home improvement stores. It's little thing you plug into the outlet and it's got three lights. Depending on which lights light up, it tells you if the circuit is wired correctly and if not, what wires are at fault. Of course this only works if you've got line voltage at the outlet. Best of luck.

[mikegideon]

Circuit tracers/breaker finders are great little tools. However, I'm not sure how well they work through walls. Well, since the GFI and the breaker aren't the cause, and you say certain things on the circuit are working while others do not, that definitely points to a loose broken connection somewhere. Lines don't "just break". Unless you have rodent issues then I'd be willing to bet that the line is fine. Check around for loose connections, including the neutrals in the breaker box. Corrosion can also lead to these types of things though I rarely see that indoors. Another nifty little tool is an outlet tester. They cost less than $5 at the home improvement stores. It's little thing you plug into the outlet and it's got three lights. Depending on which lights light up, it tells you if the circuit is wired correctly and if not, what wires are at fault. Of course this only works if you've got line voltage at the outlet. Best of luck.

Circuit tracers will work thru a wall. I've never seen a rodent chew through a solid #12 wire. They may chew the insulation off and cause a short. My bet is that a wire came loose in an outlet box, either off the back of a plug, or out of a wire nut.

[Guest bkelm18]

Circuit tracers will work thru a wall. I've never seen a rodent chew through a solid #12 wire. They may chew the insulation off and cause a short. My bet is that a wire came loose in an outlet box, either off the back of a plug, or out of a wire nut.

I have.

[jgrauman]

First things first. turn off power, remove "line" side from GFCI. cap the neutral and hot and turn on the power. remove nut on hot (black) and check volts to ground. if no power, do the same for the "load" side of the GFCI. The "Line" side should be your hot. a lot of electricians get this wrong and ruin the outlet. it will not reset, if you put in the new GFCI like the first, wrong, then it will not reset properly either.

if neither wire has voltage then you can test continuity by wire nutting the hot and ground on one side (with power off) and checking at the panel to make sure you don't have a break. check again by wire nutting the neutral and ground.

Let me know from here if all is well, my credentials are 6 years of trouble shooting electrical systems in residential and commercial.

[mikegideon]

I have.

That's one helluva critter Usually, their little heads will start smoking before they get all the way through. I've found lots of electrocuted mice over the years.

[Photoguy67]

That's one helluva critter Usually, their little heads will start smoking before they get all the way through. I've found lots of electrocuted mice over the years.

Cause of many "electrical" fires.

[Guest bigbovine]

remove nut on hot (black) and check volts to ground

Please do not remove that nut, As he says it is hot. You can easily stick the tester into that nut. Wouldnt wanna accidentaly touch that open wire would you?

[hardknox00001]

That's one helluva critter Usually, their little heads will start smoking before they get all the way through. I've found lots of electrocuted mice over the years.

Working electric signs, I have found petrified mice before in restaurant neon transformer boxes in ceilings..................Or crispy baby birds in spring time in outside neon stuff. Nothing like trying to pull one of those out of the box and they break in half..............

[nightrunner]

try replacing the GFCI receptacle with a standard outlet.