Ditto resqcapt. You need the info.
I had to troubleshoot a sign fed by an underground conduit that tripped sometimes. When it did, the current rapidly(2-3 seconds) increased from 16-17 amps to 60,70,80,trip. The underground j-box had become exposed and, depending on the weather(dry, damp, or wet ), the breaker would either hold or not. It was interesting that once the current started to flow to ground, it started low, but rapidly increased to the point of tripping . Had to re-feed overhead.