Correct, either there or above the nav desk. Both are pretty obvious, and the OP indicated having “problems with shore power”, so I wonder if the question is whether or not there is another breaker or fuse somewhere between the ac/dc distribution panel and the shore power inlet. To my knowledge, the answer to that is no, there is certainly none on my ‘82 H30, but it’s anyone’s guess what a previous owner might have added. So, as dlochner said, start at the inlet plug and follow the wire.On some of the earlier h30s, the ac/dc breaker panel was located in the forward part of the q-berth near the sole just to the port of the companionway. These were often fuses instead of marine breakers. Go figure!