Dead Electrical Circuit Troubleshooting

[DerbyDad03]

re: " By the way, I've taken this opportunity to replace some old a/c outlets, and none of the ones I've worked on so far have been hot, with the breaker on."

Please don't tell us that this means you've been replacing outlets with the breaker on, even if the oulet read dead when you started the work. Since you don't know what's casuing the problem, you don't know what could make it go away.

A loose connection in a junction box could re-connect with something as simple as someone walking across the living room floor.

Besides, it rarely makes sense to make changes to a problem situation before you know what the problem is. This is a general statement, not just related to electricity. Making changes while troubleshooting a problem introduces variables that may mask the original problem or make the tracing of steps more difficult - especially if you are going to turn this over to someone else - like an electrician. Now you've got to tell him everything you changed from the original setup which just makes the whole situation more confusing

[noname87]

Trevor,

As I said before, you need to find out what is on this circuit. So check any outlets and switches that you haven't checked yet.

A few things to check for:

1) At the circuit breaker: Test the voltage (with the breaker on) between the hot terminal of the breaker and the neutral terminal strip. Is there 120V or does the lamp on the tester light? If no, replace. If yes, turn it off and verify that the power disconnects. For safety reasons, I would make sure that only ONE hand is in contact with the panel at a time. If you replace the breaker, turn off the main breaker before removing the breaker. The pros probably don't but they are use to working inside the box, you are not.

2) With the main circuit breaker off, verify that the neutral and ground wire screws in the panel are tight.

3) If the breaker is good, then you need to check each box on the circuit. Check for power coming into the box. If there is no power then the problem will be 1) bad wire (unlikely if you haven't been working around the wires) or 2) that the power never left the previous box. Go to the the previous box and check for loose connections, loose wire nuts, loose terminal screws. If the wires are pushed into the back or the receptacle instead of being wrap around the screws then I would replace the outlet and use the screw terminals instead. Back stabbed connection can weaken over time (or so I been told). If the wires are pushed into the back of the outlet and the outlet has power DO NOT assume that the wires leaving the outlet have power. You will need to check.

4) If after checking all the boxes and you still can't find the problem then there are a few possibilities. 1) that a wire is damage between two boxes, 2) That you missed a box, 3) That a box is hidden in the walls (against code but it happens) or 4) ?

Good luck.

Phil

[Joe]

FWIW, here are some of the things I would do: 1) Turn main breaker off. Exchange output of bad circuit with another breaker. Turn main breaker on. If the fault travels the breaker is bad. Replace. 2) Turn Main breaker off. Check and tighten all ground and neutral connections. Turn main breaker on and check system functions. If everything works you found the problem. Beyond this things get more difficult. From what you have described your system may no longer be code compliant , if it ever was. You may find there are multiple wires under a single screw, or neutrals and grounds on the same bus bar, This and other poor wiring practices will need some journeyman help to set right. Good luck.

Joe

[pcgeek86]

Phil and Joe,

Those are some excellent ideas. I will try them out in detail when I get home, and post back my results. Thank you very much.

Trevor

[HeyBub]

It's not a "meter;" it's a "tester." Do you know the difference between "accuracy" and "precision?" And if most meters are 100% accurate, as you claim, why the disclaimer on digital meters?

You don't know what it is or how it works or its method of indicating voltage. I despair of your advice.

But I think we have a teaching moment:

About $15.00

[Douglas Johnson]

Are you talking about the switch loop? You're right about that. But a box with a switch in it can be carrying current to downstream devices. You can even use the hot lugs on the switch to do it. I know the gold standard is to pigtail the hoots, but it is certainly proper to have wires on light switches carrying current to downstream devices.

-- Doug

[RBM]

re: " By the way, I've taken this opportunity to replace some old a/c outlets, and none of the ones I've worked on so far have been hot, with the breaker on."

Please don't tell us that this means you've been replacing outlets with the breaker on, even if the oulet read dead when you started the work. Since you don't know what's casuing the problem, you don't know what could make it go away.

A loose connection in a junction box could re-connect with something as simple as someone walking across the living room floor.

Besides, it rarely makes sense to make changes to a problem situation before you know what the problem is. This is a general statement, not just related to electricity. Making changes while troubleshooting a problem introduces variables that may mask the original problem or make the tracing of steps more difficult - especially if you are going to turn this over to someone else - like an electrician. Now you've got to tell him everything you changed from the original setup which just makes the whole situation more confusing

I agree completely, You have an obvious open circuit, which can just as easily close and become energized, so caution should be taken. Also, why potentially complicate the existing problem by making more changes? First find and correct the problem, then move on. There are times when I have to replace all the outlets and switches in a house, and even though I am a "professional" and do this for a living, and have for over 35 years, I do it room by room, killing the power then turning back on and testing. If you take too big a bite, and something goes wrong, it just takes that much more time to find it

[Stormin Mormon]

Couple friends of mine had dead outlet in the kitchen. The problem turned out to be where the wire came from the (live) outlet, going to the dead one.

Sorta like this, crudely illustrated:

Breaker========[outlet]========[outlet]-=========[intermittent outlet]

This may not relate to your problem, but their house had back stab outlets.

[Terry]

Swap a known working breaker with the suspect one.

Changing the GFI shouldn't be necessary. Your tester will tell you if the wires in the box are hot. You can replace the receptacle for the test, but you need a GFI there when you are done. One the GFI there are "line" terminals and "load" terminals. I would put a piece of black tape on "line" piece of Romex. A piece of tape on the black and white. If you change it to a standard receptacle all the blacks go on one side and all the whites go on the other. The darker color screws is for the black wires.

I think the tester you are using is a good choice. All you need to know at this point is....is it hot.

When you are tracing the wire inside the panel make sure the white wire is tight at the bus bar.

Maybe you will have access to the attic and will be able to visually find the first box in the run.

[pcgeek86]

Alright, so I swapped two breaker lines with each other, and the problem still prevails. I think that it must be a wiring issue somewhere, but I still can't find the first item in the grouping. I know that the line going out from the breaker is hot.

I tested the garage switches, and outlets, and they area all dead too.

A co-worker of mine has a son-in-law who's an electrician in my area. I think I'm going to just have him come out and look at it. I assume it would be safest to disable the breaker for the bad circuit at this point?

You guys have all been very helpful. Thank you so much.

Thanks,

Trevor

[dpb]

[e-mail] wrote: ...

That's logical conclusion.

Did you do the exhaustive test of anything that is switched off by turning off that breaker? There are only two possibilities -- nothing on the circuit is live or one or more items are. If the former, you have basically identified the disconnect is before or at the first; if the latter, then you have at least a candidate for the starting point.

Looking at the location of the feed and the location of the dead outlets, it should be relatively straightforward to figure out what is the least linear feet of wire direction in which the run could have been made. That would be the most probable way it was done (assuming this is original wiring--if it's an added circuit, it would be more likely to be the easiest access way, not necessarily the shortest.)

If you're retiring from the field, I would recommend that, yes...

--

[David Nebenzahl]

On 4/7/2008 12:35 PM Douglas Johnson spake thus:

Yes, yes and yes. Sounds like you pretty much know how this stuff works.

[pcgeek86]

Right, so ... earlier in another post, I mentioned that I traced the wire from the breaker panel, through its conduit, and as best I can tell, it's going up, and out to the back, outdoor receptacle. I checked that outlet with my tester, and the wire is dead. I have checked all other outlets, and switches, on that side/area of the house, and have come up with nothing hot, except what's on the other, good, 1st floor breaker.

Thanks,

Trevor

[pcgeek86]

Gents,

I just discovered, with the help of a guy fixing my fire alarm this morning, that there was indeed a broken, disconnected wire. After restoring this wire, everything is working again.

Thanks again for all the input! You guys have been most helpful.

Trevor

[Terry]

Sounds too convient that the fire alarm guy found the "broken" wire.

Was the fire alarm on that breaker?

[David Nebenzahl]

On 4/9/2008 12:14 PM Terry spake thus:

Sometimes--just sometimes--one can assume good faith. Why not give the guy the benefit of the doubt here?