Locate breaker

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springerjim

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electrician
I have many multi circuits (shared neutral) on single pole breakers (not next to each other) I don't what they are feeding. when I change receptacles the neutrals are hot.
I can locate the circuit I am working on but how do I locate the second circuit breaker?
 
Before we can answer your question, please tell us what your role is. Are you the homeowner? Are you an electrician and is this a work-related issue?
 
Easy, use one of these. One clip to the disconnected neutral, the other to ground, and it will tell you which breaker it is. But be forewarned if it is two more breakers, not just one, you will probably let the magic smoke out. A little more time consuming, but much less chance of letting out the magic smoke, is to plug the tracer into different circuits that are still live, and go back to the panel to see which neutral it is. This type of tracer draws a current off the line and returns on the neutral (only if connected to the neutral, this will not work if the other lead is going to ground)
 
springerjim said:
Electrician - work related
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Thank you for clarifying that.

I am sure you know that you have a dangerous situation in your hands. If two circuits share a neutral, and if their breakers are adjacent (as they are required to be), then you get two benefits. First, you can (and are now required to) install a handle tie that will force both to be open when you open either one. That would prevent the "neutrals are hot" situation that you are now experiencing. Secondly, this assures that the two are on different phases. With breakers that are not adjacent, it is possible that two circuits from the same phase could be sharing a neutral. That could overheat the neutral and neither breaker would be able to protect it.

So when you get this particular issue sorted out, I suggest that you (at least) inform the owner that the panel is not code compliant and that a safety risk does exist. I would certainly want this fixed.
 
200204-1721 EST
I have many multi circuits (shared neutral) on single pole breakers (not next to each other) I don't what they are feeding. when I change receptacles the neutrals are hot.
I can locate the circuit I am working on but how do I locate the second circuit breaker?
Click to expand...
Try the following:

Equipment required ---

Digital voltmeter with resolution of at least 0.1 millivolt, Fluke 27.

Three prong plug with neutral and EGC brought out to banana plugs to connect to the meter. As an alternative you might want to run your own wire (an extension cord) from the EGC ot neutral bus bar in the main panel to the meter.

A 1500 W space heater to provide about a 10 -12 A current.

#12 copper wire is about 1.5 ohms per 1000 ft, or 0.0015 ohms per foot. 10 A produces 0.015 V/foot.

Procedure ---

For your circuit in question measure the voltage from neutral to EGC out at the outlet you want to work on. On a random circuit of mine without the 10 A load I read 0.2 to 0.3 V jumping around. With the 10 A load added it increased about 1 V.

A 75 ft extension cord plugged into an outlet I have at my main panel reads 1.5 millivolts, jumping around a little. This is the voltage between the neutral and EGC bus bars. With the extension cord unchanged in position, and the input shorted out voltage is less than 10 microvolts. Thus, any stray magnetically induced voltage is insignificant.

With the above information can you figure out a way to find any other circuits that may share your neutral?

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springerjim said:
I have many multi circuits (shared neutral) on single pole breakers (not next to each other) I don't what they are feeding. when I change receptacles the neutrals are hot.
I can locate the circuit I am working on but how do I locate the second circuit breaker?
Click to expand...
If the receptacles are installed correctly you have a pigtail to receptacle and you don't have to worry about a "hot neutral" as long as you don't pull apart the wire nut. If you are downstream from the point where there are shared neutrals on a multi wire circuit then you won't have a "hot neutral" even if you don't have pigtails.

If you need to be sure put an amp clamp around the neutral and test for current, start turning off breakers till the current stops.
 
Would temping in a receptacle with the open neutral on the hot and the ground on the neutral allow you to use a circuit tracer to find the other breaker in the panel?
 
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