Troubleshooting fuel pump circuit

[tortuga]

Greetings group
We have a fuel pump circuit that occasionally trips the breaker, the breaker has been replaced.
The circuit ammeters fine when were there, and of course does not trip again till after we leave.
The trips seem to happen randomly and one was reported at night after the station was closed, this makes me suspect the underground.
Its not a very long circuit it goes from a dog house underground to the next fuel island over.

My next thought is to pull the disconnect for that island (or possibly the whole place), disconnect the pump and breaker and do a quick megger the circuit to verify the underground wiring is ok.
Are there any extra safety precautions / best practices to take when testing underground cables at a gas station ?
I imagine the megger can be set to the lowest setting like 500V as they are just 120V circuits.
Thanks

 

[LarryFine]

You could try the light-bulb trouble-shooting tip. Read this thread:

Hot to neutral short on knob and tube circuit

Hello all, there are multiple rooms on the first and second floors of this circuit. After tracing, it is lights and plugs only. I was able to trace and isolate one hot and neutral going from the basement up into a first-floor wall. I was able to reconnect with the other knob and tubes that were...

forums.mikeholt.com

 

[tortuga]

You cold try the light-bulb experiment. Read this thread:

Hot to neutral short on knob and tube circuit

Hello all, there are multiple rooms on the first and second floors of this circuit. After tracing, it is lights and plugs only. I was able to trace and isolate one hot and neutral going from the basement up into a first-floor wall. I was able to reconnect with the other knob and tubes that were...

forums.mikeholt.com

Thanks Larry, great idea.

 

[LarryFine]

Thanks Larry, great idea.

Welcome. In the old days, we would just screw a 100w bulb into the fuse socket.

 

[tortuga]

The update is my co-worker stopped by there and meggered the circuit and he thinks he got .045 meg ohms or .145 megohm, either way seems a bit low and thats not even correcting to 20C

 

[ptonsparky]

The update is my co-worker stopped by there and meggered the circuit and he thinks he got .045 meg ohms or .145 megohm, either way seems a bit low and thats not even correcting to 20C

A bit.