Customer has a detached garage, two circuits are run underground in 10/3 underground cable. Two pole 15 amp breaker in house trips maybe once a day for no apparent reason, I checked connections on both ends, replaced breaker, but it still trips, there is no load on when breaker trips. I,m thinking the underground cable might be damaged, but I don't know. I don't have time waiting around the house waiting for it to trip. How would you guys troubleshoot this problem, thanks for any replies.

I had the same problem sometime ago. Finally i came to the conclusion that it would be the UF cable feeding the BBQ section. So, I hooked up a FLUK 88 meter in series with the circuit and put the setting on the MIN/MAX/AVE setting. Then about evry 5-10 minutes the meter would register 150A,225A or some very high amps like that.(cant remember the exact number but it was very high without any load connected) Any way, I disconnected the UF cable and waited for another 10 Minutes nothing tripped. Reconnected the UF cable after 2 minutes it tripped. So the problem was from the cable somewhere.


Good Luck
Edward

[This message has been edited by Edward (edited 09-29-2004).]

I would use a megger. Ground faults can show on an ohmmeter, but it's a little unreliable.

Sounds like you have a fault.
We usually go out and locate the line and paint it.
We then use a fault locater.Isolate both ends,hook up one end to the fault locater voltage output,Adjustable up to 1700 volts.We have a meter with 2 insulated probes connected to it . we poke into to ground on top of the circuit. and follow the needle until we are right on top of the center signal.Dig down and walla,hole in cable. repair it with a heat shrink connector kit,and your ready to reconnect and energize. Works everytime.