Talonewo
Senior Member
Let me start with my priorities are; Safety then corrosion THEN ABYC standards.
In an effort to constantly learn and understand my boat I have been reading Nigel Calder and John Payne books on marine electrical and neither of them suggest a system like mine, Charles Industries isolation transformers has some diagrams that are close.
We all know previous owners of our old boats have been known to do wacky stuff and everything should be suspect. But on my boat, 40 year old steel hull (aluminum house)DeFever, based on what I have seen and the receipts I have found, for the most part he did an excellent job and nothing gives me any reason to doubt his work. The only reason I'm questioning it is because it doesn't match any of the books, the white neutral and green ground are not used.
My boat has 100 amp service, two of the standard marinco 50 amp plugs side by side(they are mounted to an isolating material, i.e. don't make contact to the aluminum house), immediately behind the shore power receptacles the 8 wires are all combined into 4 (red to red, black to black, etc) and the white and green terminate there. The red and black feed into a 100 amp circuit breaker the out put of that CB splits in two directions, one goes to the 240v distribution panel the other goes to a transformer, single phase, 8KW, two wire 240v in three wire 120v out, the standard white black green. The transformer output feeds the 120v distribution panel. In addition, the transformers white neutral is connected to the green bus bar which connects to the DC negative bus bar.
I have searched the web and can't find any information about the brand or make of the transformer I assume it is an isolation transformer, is a transformer an isolation transformer construction? From what I read in ABYC it would mater where the green is attached to the shield. The identification label is difficult to read but I think it says manufacture date of 12-97.
This setup is basically "method 2" of the recommended installation of Charles Industries current 50 amp isolation transformer. The difference is that the 240 supplying the boats distribution panel does not go through an isolation transformer, it is straight shore power 240v red and black.
As for the lack of using shore power green, I don't see that as a problem because all 120v load green wires on the boat are connected to the white natural out of the transformer.
Am I safe using the 240v shore power without the shore power green?
Is the green bus bar only associated with 120V? is there any relation to the 240v circuit?
I understand for 120v loads you should connect the case of the item to the green bus bar, I installed several 240v air conditioners, is there any purpose or value in grounding the case of a 240v load to the boats green bus bar?
In an effort to constantly learn and understand my boat I have been reading Nigel Calder and John Payne books on marine electrical and neither of them suggest a system like mine, Charles Industries isolation transformers has some diagrams that are close.
We all know previous owners of our old boats have been known to do wacky stuff and everything should be suspect. But on my boat, 40 year old steel hull (aluminum house)DeFever, based on what I have seen and the receipts I have found, for the most part he did an excellent job and nothing gives me any reason to doubt his work. The only reason I'm questioning it is because it doesn't match any of the books, the white neutral and green ground are not used.
My boat has 100 amp service, two of the standard marinco 50 amp plugs side by side(they are mounted to an isolating material, i.e. don't make contact to the aluminum house), immediately behind the shore power receptacles the 8 wires are all combined into 4 (red to red, black to black, etc) and the white and green terminate there. The red and black feed into a 100 amp circuit breaker the out put of that CB splits in two directions, one goes to the 240v distribution panel the other goes to a transformer, single phase, 8KW, two wire 240v in three wire 120v out, the standard white black green. The transformer output feeds the 120v distribution panel. In addition, the transformers white neutral is connected to the green bus bar which connects to the DC negative bus bar.
I have searched the web and can't find any information about the brand or make of the transformer I assume it is an isolation transformer, is a transformer an isolation transformer construction? From what I read in ABYC it would mater where the green is attached to the shield. The identification label is difficult to read but I think it says manufacture date of 12-97.
This setup is basically "method 2" of the recommended installation of Charles Industries current 50 amp isolation transformer. The difference is that the 240 supplying the boats distribution panel does not go through an isolation transformer, it is straight shore power 240v red and black.
As for the lack of using shore power green, I don't see that as a problem because all 120v load green wires on the boat are connected to the white natural out of the transformer.
Am I safe using the 240v shore power without the shore power green?
Is the green bus bar only associated with 120V? is there any relation to the 240v circuit?
I understand for 120v loads you should connect the case of the item to the green bus bar, I installed several 240v air conditioners, is there any purpose or value in grounding the case of a 240v load to the boats green bus bar?
