shore power problem

I had some work done on my 94 bounder pusher.where the batteries where discounted. rear main seal ,work by cummins. to what extent I don't know if they discounted all of them or just the 1 battery.but now when I go to plug into shore power it blows the c/b.so I traced the power cord and it seems to run to the inverter under the bench seat .has any body else have a problem with their shore power. I cant find a correlation between undoing the battery vs blowing the c/b any thoughts