tmiller1116
Veteran Member
I imagine that somehow this has been covered before... but here goes... I am not an electrician.. I understand enough to get by...
When I am hooked to 30amp120v shore, I can put a multi-meter on my power transfer switch connections and see 115vac. Start some item on the boat like a heater or microwave and it drops to 111vac. Start another thing and it drops to 108vac. plug in a lamp and it drops to 104... (all numbers are rough and vary but you get the idea). I can also plug in a device called a kill-a-watt and watch the same thing happen....
Testing also shows all AC outlets have an open ground.
When running the gennie, this problem does not occur. Even the open ground is gone.
At first I thought it was in the transfer switch, since this is the meeting point of the power sources... so got a new one and the problem still exists... double checked all my grounds.. everything is tight...
(side note: previous owner survey 3 years ago also showed an open ground... I thought it might be the electrical socket on the side of the boat, but he replaced that a few months ago.)
thought it might be the shore power cable, so brought over another one and the problem is still there...
I cannot put a load on the dockside plug in to see if the issue is there and if voltage drops at that point....
so what the heck do I do now?????
This boat has one piece of equipment that I am unfamiliar with and that is a 120/240 step up transformer or some such item.. I understand it was originally installed to run the 240vac oven, but that was removed and propane installed instead.. the transformer is still there and there is still some 240v lines up in the electrical box... the shore power runs through the transformer and up to the transfer switch... it has a ground that seems solid though...
When I am hooked to 30amp120v shore, I can put a multi-meter on my power transfer switch connections and see 115vac. Start some item on the boat like a heater or microwave and it drops to 111vac. Start another thing and it drops to 108vac. plug in a lamp and it drops to 104... (all numbers are rough and vary but you get the idea). I can also plug in a device called a kill-a-watt and watch the same thing happen....
Testing also shows all AC outlets have an open ground.
When running the gennie, this problem does not occur. Even the open ground is gone.
At first I thought it was in the transfer switch, since this is the meeting point of the power sources... so got a new one and the problem still exists... double checked all my grounds.. everything is tight...
(side note: previous owner survey 3 years ago also showed an open ground... I thought it might be the electrical socket on the side of the boat, but he replaced that a few months ago.)
thought it might be the shore power cable, so brought over another one and the problem is still there...
I cannot put a load on the dockside plug in to see if the issue is there and if voltage drops at that point....
so what the heck do I do now?????
This boat has one piece of equipment that I am unfamiliar with and that is a 120/240 step up transformer or some such item.. I understand it was originally installed to run the 240vac oven, but that was removed and propane installed instead.. the transformer is still there and there is still some 240v lines up in the electrical box... the shore power runs through the transformer and up to the transfer switch... it has a ground that seems solid though...