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zappy12 12-09-2012 09:46 PM

Dead circuit, couldn't find problem so tied into second circuit
 
My girlfriend lost power to several receptacles and lights in her home while using an old vacuum cleaner that pulled a lot of electricity. She told me that first the room lights and power to the receptacle she was using turned off, a minute or two later they came on, and then they shut off again for good and were off for the better part of a day until I got there.

I cycled all the breakers with no effect. I then removed the panel cover and checked each breaker with a circuit tester by using a tester on the circuit breaker screw and ground, and checked each hot wire while confirming I got a light on the tester.

So the breakers are all good, no broken black wires connected to the breaker screws, but no power to outlets and receptacles which are presumably all on the same circuit. I pulled every dead outlet as well as every live one that was adjacent or close to the dead ones and found no problems with any of the connections in any of the boxes or fixtures nor any power in the dead fixtures. The wiring is very strange in the home, there used to be two kitchens, 4 breakers do not seem to feed any outlets or lights in the home so I shut them off completely as I labeled the rest. The dead circuit (believe it or not) includes the garage, part of the basement, the boiler, and 3 gfi outlets in 3 separate bathrooms, one in the basement and 2 on the main floor. I checked each bathroom gfi, there's only one black and white in each box so that's not the problem.

After checking every possible fixture, box, receptacle, switch, etc, I figure that the bad connection is probably buried in a wall somewhere and not traceable or fixable.

So I found a nearby outlet from another circuit which is fed from a 15 amp breaker, and ran a 12-2 wire to a nearby dead outlet and all the lights and receptacles now work. They worked after only connecting the black wire indicating that the problem is definitely an open hot lead somewhere, but I connected the whites as well.

The circuit I tapped into powered only a few outlets in the basement as well as a half a bathroom and the only time the circuit tripped so far was when all the garage lights were on and using a vacuum so the amperage of the new combined circuit seems adequate.

My concern is that if the power returns to the formerly dead circuit now I have 2 circuits feeding to several receptacles and lights and also, I have effectively reversed the direction of the electrical flow to the circuit on at least some of the receptacles by tapping into one that is somewhere in the middle of the circuit that went dead.

What are the potential problems/safety risks of leaving it as is.

I have shut off 4 breakers that don't seem to provide power to anything in the home, so I figure 1 of them is the circuit that went dead but there's no way to be sure.

joecaption 12-09-2012 09:57 PM

May now end up with 220 volts going to that circut if it comes back and distroying anything that's pluged in.
Where the outlets back stabed? Or where the wires wrapped around the screws?
If back stabbed, change them to wrapped around the screws.
And you checked for a tripped GFI, right?
With that wiring it could be most anywhere.
If this is her house that she owns I'd suggest getting a real electricion out there to do some rewiring to get at least up to code.

zappy12 12-09-2012 10:05 PM

Joe, thanks for your fast response.

Some of the outlets were backstabbed but I checked for power coming in and going out on all live receptacles and found none where power went in and didn't come out on the backend so the problem is not a defective back stabbed outlet.

All the GFIs in the affected circuit only had one black and white in each box, so they're dead ends, with no outlets downstream and they had no power feeding into them from the one wire.

So if the power comes on, it wouldn't cause a short with both hot leads coming in contact with each other?

I thought if they were coming from circuits that were on the same phase it would do nothing except increase available amperage to the circuit, but if they were on different buses then it would cause a 240 volt short and throw at least one of the two breakers?

And yes, the way that house is wired the problem could be anywhere, most likely buried in a junction box behind a wall so what could an electrician do if the problem isn't in an accessible junction box?

jbfan 12-10-2012 06:37 AM

You need to call an electrician!
She own this house?

AllanJ 12-10-2012 07:30 AM

Do you know what breaker in the panel goes with the dead circuit?

You could run the cable from a live receptacle to one of the dead receptacles to re-energize the dead circuit provided you do at least one of the following:

1. Remove the hot and neutral of the dead circuit from the panel breaker and neutral bus respectively and withdraw those wires from the panel and tape them off outside. Label them as going to a circuit that now has another feed to the panel.

2. Unhook the feed, both hot and neutral (you MUST figure out which cable) from the receptacle on the dead circuit where you are hitching up the new cable. Tape off these wires and curl them up inside the box.

Jim Port 12-10-2012 07:45 AM

I suspect a loose backstab was missed.

kbsparky 12-10-2012 08:00 AM

ANY outlet that is backstabbed with aluminum conductors should be replaced ASAP!

TTW 12-10-2012 08:46 AM

This OP never mentioned aluminum...

zappy12 12-10-2012 09:58 AM

Quote:

Originally Posted by jbfan (Post 1070055)
You need to call an electrician!
She own this house?

Yes she owns the house.

Quote:

Originally Posted by AllanJ (Post 1070080)
Do you know what breaker in the panel goes with the dead circuit?

I am not certain which breaker goes to the dead circuit. I think I have it narrowed down to 4 breakers which do not appear to supply power to anything in the home but they could have been used for one of two kitchens that apparently used to be there and they could lead to junction boxes that are buried behind sheetrock for all I know. I have flipped those breakers off. There is another breaker that appears to feed only one socket that one has only one wire going into it's box and there's yet one more breaker that feeds two sockets and I have checked the connections in those boxes. For all I know one of those could be on the dead circuit and the break is somewhere after them.

Quote:

Originally Posted by AllanJ (Post 1070080)
You could run the cable from a live receptacle to one of the dead receptacles to re-energize the dead circuit provided you do at least one of the following:

1. Remove the hot and neutral of the dead circuit from the panel breaker and neutral bus respectively and withdraw those wires from the panel and tape them off outside. Label them as going to a circuit that now has another feed to the panel.

I don't know which circuit it is.

Quote:

Originally Posted by AllanJ (Post 1070080)
2. Unhook the feed, both hot and neutral (you MUST figure out which cable) from the receptacle on the dead circuit where you are hitching up the new cable. Tape off these wires and curl them up inside the box.

That won't work, the wires that were originally "feed" wires from the now dead circuit are now acting as "load" wires to carry the current from the live receptacle back up the circuit in the reverse direction from before, that's how the circuit is now being energized.

Quote:

Originally Posted by kbsparky (Post 1070112)
ANY outlet that is backstabbed with aluminum conductors should be replaced ASAP!

The wiring is all copper.

AllanJ 12-10-2012 10:51 AM

It is not permissible for there to be more than one path (either hot or neutral) from any receptacle, light fixture, etc. back to the panel. The cable you have installed, as you described it, is totally unsafe.

zappy12 12-10-2012 11:14 AM

Quote:

Originally Posted by AllanJ (Post 1070232)
It is not permissible for there to be more than one path (either hot or neutral) from any receptacle, light fixture, etc. back to the panel. The cable you have installed, as you described it, is totally unsafe.

Well at the moment there is only one path back to the panel on the hot because the original hot circuit is broken somewhere. I suppose I could disconnect the neutral from the circuit I tapped into to energize the dead circuit, which is pretty much why I posted this thread, to find solutions to the problem.

Telling me that "it's unsafe" isn't really all that helpful especially since you really don't say "why" it's unsafe other than it's not permissible.

mpoulton 12-10-2012 12:15 PM

It's unsafe because one of two things can happen, depending on whether the two breakers are on the same leg or opposite legs. If they are on the same leg and the loose connection reconnects itself (which is pretty likely at some point), then the circuit would have twice the allowable current available, and also would require that both breakers be turned off to be safely de-energized. This is bad. Also, current flow through the loose connection may cause severe heating and start a fire. You'd never notice the problem until it's too late, since there would be no apparent malfunction (flickering lights, loss of power) because the second breaker would continue feeding the circuit in parallel.

If the two breakers are on opposite legs, then spontaneous re-connection of the loose connection will cause a 240V dead short. That's obviously not good.

TTW 12-10-2012 12:22 PM

You might be able to figure it out with a tone tracer, after, of course, killing the main. Possibly using the neutral and ground, but you would have to do some serious neutral disconnecting.

zappy12 12-10-2012 12:51 PM

Quote:

Originally Posted by mpoulton (Post 1070288)
It's unsafe because one of two things can happen, depending on whether the two breakers are on the same leg or opposite legs.

If the two breakers are on opposite legs, then spontaneous re-connection of the loose connection will cause a 240V dead short. That's obviously not good.

Thank you.

This is a very useful post and gives me information I didn't have before.

dougp23 12-10-2012 07:59 PM

Not an electrician, but have seen similar "mysteriously no longer working" outlets, and a couple MONTHS later, mysteriously start working again.
I also think you may have had a loose back stabbed connection, and when you pull the outlet out for testing, it snugged in. when you pushed the outlet back into the box, it unsnugged - breaking the connection.
Don't fool around with what you have done. Definitely call a professional. You could burn your house down. Seriously.
Again, not a pro here, but some things are better left to the pros.


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