Hi, I am having some issues with a cellar cooler....basically the unit originally would only run for a few seconds then trip the breaker. I changed the electric kit and since then will run for long periods but for no apparent reason will trip out. I found the oil to be a tad low so topped it to the correct level and still having the same problem, as far as I'm aware the problem started through the heat wave we've been having and is still doing it. The gas pressures seem fine as it's running with a full sight glass and has on a couple of occasions got down to temperature. I've checked all wiring and can't find any waring or arching, the maintenance guy has swapped the breaker to check it's not that, the condenser coil is clear as a whistle so very confused on what could be causing it as I've never seen a system do anything like it before. The only other thing that has been found is, when the maintenance guy was swapping the breakers over to test, the live and neutral wires for a relay dropped out and looking at it closer the live has been arching on the terminal. Was considering swapping it for a new one to see if the loose wires may have damaged/weakened the relay and perhaps this could've been causing the unit to trip.
I'm hoping someone may have some clues or come across something similar and perhaps give me any ideas on what the issue could be.

The compressor is a maneurop MT 18 compressor and running on r22.

Thanks