We just purchased a used boat with a magnum ms2000 inverter/charger. When the boat was removed from the water we had a small dehumidifier plunged in and we had the shore power connected and everything seemed to be working. We return to the boat a month later to discover the gfci at the pedestal was tripped. I unplugged the shore power reset the gfci and it trips instantly with all the boat breakers and switches turned off. I tested the shore power connection on the boat and the ground and neutral are linked together causing what seems to be a short? The inverter works fine but I wasn’t able to confirm the charger was working. The unit is not throwing any codes And from the logs it was serviced approx six months ago and a new board was installed. Im just not familiar with inverters and any help would be greatly appreciated. Should the nuetral and ground have continuity when everything is turned off on the panel including the invertor switch?