Open 120 v circuit

[Scottzohere]

Im trying to locate an open in a circuit to second floor of a late 1940’s cape. 1 bedroom, bath and half second bedroom have no power at receptacles and ceiling fixtures. When I got to house no breakers were tripped and all circuits leaving panel are hot. It was reported that they may have heard a noise around time lights went out. I have removed and inspected both ceiling fixtures and all the outlets In the affected rooms. No signs of any heating/arcing. I have read continuity on the hots from the switches to the fixtures, and can read continuity to the hots on the outlets as well from the other outlets, switches and fixtures.
I tried using a Klein ET 450 tracer and a Greenlee CS 8000 tracer from the dead fixtures and outlets to try and find the BX armored cable in basement. I’ve tried using a ground prong from another circuit during my trace to strengthen signal, as well as same circuit. I’ve tried tracing from the neutral to the BX per suggestions in the individual tracers literature. All these have provided inconclusive results. ie; signal reading on multiple cables. I’ve opened as many junction boxes as I can get to in the basement, but all the hots down there are reading energized with NCV meter. Remodeling of basement many years ago for a commercial enterprise are making it extremely difficult to hand over hand the cables from breaker box to the point where they go upstairs. I’m trying to avoid dismantling drop ceiling/partitions to trace where cable I’m looking for is. I’m going to try a Bosch wall scanner tomorrow to see if I can find where the BX cable is going from second floor thru first and then to basement. In the hopes then I’d be able to trace the cable back to breaker panel.

Any thoughts or suggestions on how to locate would be greatly appreciated.

 

[hillbilly1]

I would look for a tripped or bad gfi, if it is bx, you should have a ground reference if everything’s continuous. Check for an open to ground on the neutral, if it is also open, it is a strong possibility that it is a gfi receptacle tripped a lot of gfi receptacles open the neutral too when tripped.

 

[Scottzohere]

I would look for a tripped or bad gfi, if it is bx, you should have a ground reference if everything’s continuous. Check for an open to ground on the neutral, if it is also open, it is a strong possibility that it is a gfi receptacle tripped a lot of gfi receptacles open the neutral too when tripped.

I’ll double check that tomorrow. There aren’t many Gfi’s in this house. The one I know of I installed last year when replacing an outdoor receptacle. I also went around entire house with an outlet tester the other day and didn’t find any issue. The only two I didn’t test were being used and the appliances were on at the time. That’s why I pulled all the outlets that are dead, I was looking for damaged outlet perhaps not feeding thru. Thx for the reply

 

[LarryFine]

Plug an extension cord into a working, known-properly-wired receptacle, and carry the female end around with you and use a solenoid tester to test for voltages between the cord hot and the circuit neutral, and between the cord neutral and the circuit hot.

 

[synchro]

I tried using a Klein ET 450 tracer and a Greenlee CS 8000 tracer from the dead fixtures and outlets to try and find the BX armored cable in basement. I’ve tried using a ground prong from another circuit during my trace to strengthen signal, as well as same circuit. I’ve tried tracing from the neutral to the BX per suggestions in the individual tracers literature. All these have provided inconclusive results. ie; signal reading on multiple cables.

I think you'd have more success by trying to trace the outside metal of the BX instead of trying to energize the hot or neutral inside of the BX, because they will be sheilded. To do this, you want the transmitter to send a test signal current through a closed loop that includes only the section of BX that you want to trace (instead of just a test signal voltage, without a closed circuit to provide a path for a test signal currrent). The test signal current will produce a magnetic field along the BX at the frequency of the test signal, but other sections of BX that are not within this closed circuit will not radiate as much test signal. You would create this closed circuit around the length of BX using a long wire or just one wire of an extension cord. And so this long wire, the section of BX being tested, and the transmitter with red and black leads would all be in series inside this closed circuit. You would want to space the long wire at least several feet away from where you think the BX is, because you don't want the their magnetic fields to interfere with each other.
This long wire would go down to the basement and connect to the outside of the BX that feeds the second floor dead circuit, if it's accessible. Otherwise, connect the wire to the panel ground bar or enclosure. On the second floor, connect the other end of this wire to the black lead of the transmitter. Connect the red lead of the transmitter to a ground on one of the receptacles, using another length of wire as necessary. Again, keep the wire and transmitter away from the BX. This will complete a closed circuit with the transmitter that includes the section of BX down to the basement so that you should be able to trace it.
Actually, I think you could reverse the red and black leads of the transmitter and it shouldn't make much difference when feeding a closed circuit.

To see how this closed circuit tracing technique will work out, you could first try it between two different receptacles upstairs. Just put the transmitter in series between the grounds of the two receptacles by using a length of wire routed at least several feet away from where you're tracing the BX. Hopefully, you should find that the received signal is noticeablly weaker for other sections of BX on the same branch circuit that are not within the closed circuit test loop between the grounds of the two receptacles.

 

[gar]

230414-1005 EDT

You can trace the path of a conductor, even in a magnetic conduit, by only passing current thru one conductor inside the conduit.

A 1500 W space heater puts about a 12 A current thru a conductor from a 120 V source. If the return path for said current is a sufficient distance away from the conductor being traced, then I can get a useful signal from the current carrying conductor. A 2000 turn coil, and an a millivolt meter, can trace that conducting wire behind walls and in conduit.

If there is too much noise, then add a tuning capacitor in parallel with the coil.

Do an experiment wit a 10 ft length of thin wall, and see what you get.

.

 

[mtnelect]

If they used the wiring devices for termination instead of "Pig Tailing" that could be the problem.

 

[kwired]

Did you figure out if you have lost the grounded or the ungrounded conductor at the dead outlets?

You can then hook tracer between an outside of the bad circuit and the good conductor of the bad circuit and at least find which breaker is supposed to be supplying it which will help determine if there is anything ahead of the bad spot that is still working.

Taking out the "first non working" outlet won't always be where the bad connection is, could very well be the outgoing conductor at the "last working" outlet that has failed.

Checking in J boxes with a NCV tester isn't necessarily a good test for this situation, capacitive coupling that they work off of can leave many things testing "hot" that normally wouldn't be or even leave grounded conductors giving you a "hot" signal in some conditions.