Hello all

I have a dedicated 20 amp circuit that feeds 4 outdoor recepticals spaced
around my yard. There is probably a total of 300 feet of 12 AWG Romax
underground wire used, burried about a foot deep in our (very) sandy soil.
This setup has been working fine for years, until the other day when the
circuit breaker popped. We reset it, and things were fine until the middle
of the next night...I thought we had a power failure... turns out the
circuit breaker popped again, along with the upline main breaker that has
all the 110v stuff going through it for the whole house. The only time I've
ever seen this upline breaker go was when we had a lightning strike a few
years back. Since then, the upline breaker has not popped again, but the 20
amp breaker pops about once every 24 hours. When the breaker is reset,
things appear normal. A clamp on AC ammeter shown 0 amps when nothing is
plugged in, and reads correctly (4 amp) when the normal load is connected (a
couple of pond pumps that run 24-7). I've checkec the voltage at all the
outlets with a volt meter and all looks fine. I even swapped the circuit
breaker with another thinking maybe it was just a bad breaker.

Anyone got an idea of what could be going on? I'm stumped.

Thanks

Dan