random tripping of breaker troubleshooting help please

[mjf]

Well ? What did you fine and what, what, What ? ? > ? :happyyes:

:thumbsup::thumbsup::thumbsup:

 

[templdl]

I would certainly urge you to take Dave's suggestion. I would also move the circuit to another slot in the panel to see if there is something about the panel itself. It is possible that someone borrowed the neutral for another circuit, but that would not overload the breaker, I think.

It similar to keeping on replacing parts of an item that doesn't work until it finally work never really finding out what the actual cause is.
So often I have gotten complains that when a breaker nuisanse trips the breaker in defective an thee is a request for a warranty replacement. It's easy to do. Keep on moving the breaker, reconnecting the circuits until luck will have it that the problem goes away. All to often products that stopped working are taken apart to find a cause but finding none are put back together again and then it starts working. What was wrong with it, they have no idea.

 

[Sierrasparky]

Check for ground fault.
Put a GFCI breaker in.
could there be a moisture issue with a staple driven through?

 

[Galt]

Cad point nailed it but the radio needs to be on AM band.

 

[kevyank1918]

Sorry for the delay. I went back over there this weekend and disconnected at home run box and the breaker has not tripped yet (usually trips within 24 hours, 48 at most says customer), so time to go back and disconnect at a different junction. I've never used a megger before only know about it, can you give me some more information on it. What are the pros and cons in this situation? Would it definitely trip out the bad wires even though the regular tripping is intermittent? The customer is ok with the pace that we are going with the disconnecting of junctions as they do not use this room/bathroom, in that case would you prefer to go in with megger or disconnecting as we are currently doing? Still no patterns, weather, time, etc.; still nothing else off in house so still thinking staple, hungry mouse, etc. Thanks for all the awesome suggestions/input.

 

[GoldDigger]

Sorry for the delay. I went back over there this weekend and disconnected at home run box and the breaker has not tripped yet (usually trips within 24 hours, 48 at most says customer), so time to go back and disconnect at a different junction. I've never used a megger before only know about it, can you give me some more information on it. What are the pros and cons in this situation? Would it definitely trip out the bad wires even though the regular tripping is intermittent? The customer is ok with the pace that we are going with the disconnecting of junctions as they do not use this room/bathroom, in that case would you prefer to go in with megger or disconnecting as we are currently doing? Still no patterns, weather, time, etc.; still nothing else off in house so still thinking staple, hungry mouse, etc. Thanks for all the awesome suggestions/input.

The megger applies a controlled high voltage to the points under test. This allows measurement of very high resistances without having to measure excessively small currents and it also stresses the insulation to a point which a simple battery powered ohmmeter would not do.
But to help you with this kind of intermittent fault, you would have to either have a fault which showed up as a high but lower than normal resistance all the time and occasionally went to a low resistance or have a megger which applied more than the normal line voltage (120V times 1.414) but still less than the rating of the insulation (600V AC RMS or 850V DC).
The chances are pretty good that the fault would show up this way, but no guarantee.

 

[kevyank1918]

The megger applies a controlled high voltage to the points under test. This allows measurement of very high resistances without having to measure excessively small currents and it also stresses the insulation to a point which a simple battery powered ohmmeter would not do.
But to help you with this kind of intermittent fault, you would have to either have a fault which showed up as a high but lower than normal resistance all the time and occasionally went to a low resistance or have a megger which applied more than the normal line voltage (120V times 1.414) but still less than the rating of the insulation (600V AC RMS or 850V DC).
The chances are pretty good that the fault would show up this way, but no guarantee.

Thank you, this is also pretty time consuming as well, correct? Would you start at random points in the circuit and leave devices in or do you have to go ahead and pull out devices? I guess you can go device to device disconnecting until you find the problem instead of pulling out all devices, etc. in advance.

 

[GoldDigger]

Thank you, this is also pretty time consuming as well, correct? Would you start at random points in the circuit and leave devices in or do you have to go ahead and pull out devices? I guess you can go device to device disconnecting until you find the problem instead of pulling out all devices, etc. in advance.

The important factor is that the megger will apply a high voltage to the wire and anything connected to it. So whatever you do you must not have any electronic or motor devices, or even GFCI outlets attached to the wire(s) you are testing at any given time. Just having the devices switched off is not good enough, since the megger voltage may be higher than what the switch is rated for.

 

[kevyank1918]

The important factor is that the megger will apply a high voltage to the wire and anything connected to it. So whatever you do you must not have any electronic or motor devices, or even GFCI outlets attached to the wire(s) you are testing at any given time. Just having the devices switched off is not good enough, since the megger voltage may be higher than what the switch is rated for.

Thanks again. How often do you use the megger, what situations does it come in handy, troubleshooting only? Never really though much about the megger, but know it's on my mind, I was reading through the general specs on a new project I was starting the other day, and one of the specs calls for all circuits to be tested with non-destructive megger, which is a generic spec know that I think of it on a lot of projects that I do, but I've never done it.

 

[gar]

131014-1905 EDT

kevyank1918:

When you break the circuit looking for the problem do a binary search.

This means first break it in the middle. If it still fails then break at the 1/4 point. If it does not fail with the 1/2 point break, then reconnect the mid point and break at the 3/4 point, and retest. Repeat this procedure until the problem is found.

You will need to look for parallel paths.

Also possibly stress the circuit with a 1500 W heater at the end of the circuit. This also provides a means to map out the path of the circuit.

.

 

[kevyank1918]

131014-1905 EDT

kevyank1918:

When you break the circuit looking for the problem do a binary search.

This means first break it in the middle. If it still fails then break at the 1/4 point. If it does not fail with the 1/2 point break, then reconnect the mid point and break at the 3/4 point, and retest. Repeat this procedure until the problem is found.

You will need to look for parallel paths.

Also possibly stress the circuit with a 1500 W heater at the end of the circuit. This also provides a means to map out the path of the circuit.

.

Thanks, I didn't think about the heater that is a good idea. Know that I have ruled out the homerun I will continue with binary search. Typically this is the way I do it, however I was liking the idea of staple on floor joists maybe walking through the house tripping. Not much on the circuit so it shouldn't take to many tries. Thanks for the help

 

[nicholaaaas]

looking for a few ideas to help with troubleshooting breaker tripping....customers house breaker is tripping at random times (never while on sight) here's info I have done so far:
-breaker feeds bathroom exhaust fan, bathroom vanity light, 1 bedroom light and receptacles in that bedroom
-breaker is not arc fault or gfi standard square d qo load center snap in breaker
-breaker trips at random times with nothing plugged in or lights on with this circuit, sometimes while thay are at work; sometimes in the evening while they are sleeping, sometimes while they are at home
-I have changed breaker in the panel and checked panel connections and bus bar where breaker snaps in (also moved to different location)
-14/2 wiring, not sharing neutral with another circuit
-checked devices, lights, fan for wiring problems
-took amp draw with circuit on and everything turned off to make sure no other load on circuit that I am unaware of
-spot traced wire from panel to 1st entry point does not appear to have any junctions underhouse (when I say spot traced I followed group of wires from under panel to where they enter walls under house and there were no junctions I did not actually follow that wire all the way knowing for sure that was right, this was on my 1st visit I probably need to 100% verify)
-my next idea is to break joints at halfway point, or somewhere along the line and see if it trips and go about with that way of process of elimantion

would like some ideas/advice/questions on stuff I've checked to see anything I am missing or am not thinking to check

thank you

No mention of an ohm meter. if it's intermittent you are probably going to need a sensitive one. love my 289 for situations like these

 

[Little Bill]

Thanks, I didn't think about the heater that is a good idea. Know that I have ruled out the homerun I will continue with binary search. Typically this is the way I do it, however I was liking the idea of staple on floor joists maybe walking through the house tripping. Not much on the circuit so it shouldn't take to many tries. Thanks for the help

I forgot who, but someone suggested putting in an AFCI breaker. If its a staple, the AFCI will probable never even set/latch. This is one time I'm actually in favor of an AFCI breaker.
Or try just a GFCI breaker. Either option could be a lot cheaper than all the labor you could be charging in the search/re-search you are doing now.

Of course, if either of the breakers fail to latch you still have to find where the fault is but at least you will know what is causing it.

One more thing, you might try and put an amp clamp on the line in the panel if you have one that records high/low readings. Just make sure you have fresh batteries and leave it in place until the breaker trips. That would let you know if it is tripping on overload or not.

Keep us posted!

 

[cadpoint]

A Stitch in Time

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