Stardog wrote:
enblethen wrote:
It appears that you have a detachable cord. The twist lock end plugs into the rig.
If shutting off circuit breakers in the rig allows to plugged into shore power, the issue is in twist lock connector on the rig or the junction box adacent to it.
Using a meter set to ohms, there should be no continutity between any of the pins. Breakers off in rig and shore power cord disconnected.
Breakers off in the rig, shore power disconnected, I have almost zero ohms of resistance between these two spades.

How about between the hot side and the neutral or the grd... you should have zero there too with everything off.
I suspect either your adapter is bad/wrong or you don't have the cord attached at the trailer properly.