Have RV Questions? Ask an RV Mechanic Online.
It may be you shorted out the water heater element if no water was hooked up. Which fan did you turn on? The A/C or some other?
What is on that circuit that is tripping all the time? Do you have a schematic in the load center that would tell you? If this is the A/C circuit, I would get up on the roof and take the cover off the A/C and see if there are wasp's nests on the fan blade. A common problem in units that have been sitting a long time. Clean them all out and spin the fan blade (WITH THE POWER OFF) and spray some WD40 on the shaft where it goes into the motor and spin it a few times to make sure it isn't bound up. Let me know what happens.
Just checking back in to see if you were able to track down the problem in that circuit and if you need more input from me on this?