shellyp81 avatar image
shellyp81 asked

Installing the Isolation Transformer 3600/Auto on Boat


Per the installation manual figure 4a, when the boat is floating the connect the PE wire coming from the input PE terminal J34A to male push-on connector J34A1 so that the input and output are isolated from each other.

If the boat is on shore for maintenance, the PE connector in the boat needs to be disconnected from J34A1 and then connected to J34 (shown in green) For safety reasons.


I would like to understand the safety reasons for this wiring change? Can more information be provided? This is an annoying thing to remember to do when hauling/launching.

If it must be done, can I install a remote switch so we don't have to play with the wires in an inconvenient location every time the boat is on land and relaunched?

Isolation Tranformer
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1 Answer
boekel avatar image
boekel answered ·

This is because, if there is a live wire contacting the hull, the boat would be under voltage and anyone touching it could get shocked. With the hull connected to ground, a breaker should react.

If the shore power connection is protected by a 30mA RCD I think you don't need to connect it, as 30mA is a safe level, but don't quote me on this, local regulations can also make a difference.
(please correct me if this is wrong)

I know a lot of shipyards don't have 30mA rcd's because they would trip all the time, so your hull needs to be grounded to the shore power then.

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Pat Davitt avatar image Pat Davitt commented ·

I agree with Boekel. Once a vessel is hauled, it electrically is no longer a vessel, but a land based structure like your house. A proper ground must be assured.


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kai avatar image kai ♦ commented ·

While RCD may provide technically protection, I suspect regulations may also require earthing regardless of RCD.

fwiw, that's the case in australia.

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