Reverse polarity on a boat

Hello,

My question is regarding boat electronics.

I have a boat, and I'm using isolation transformer in order to transform 220V to 110V. Recently, the boat's reverse polarity indication light is on. I've opened the circuit to see how this indication is measured and saw that there is a diode and led connected between the neutral and the ground.
Then, I've realized that in the current situation the output of the transformer is basically floating, therefore the neutral line can have any voltage. One of the solution that I've seen online is connecting the neutral line at the output of the transformer to the boat's ground. So I have several questions about it:
1. Is there advantage in connecting the neutral to the boat's ground over working with floating voltage?
2. Is it ok to make this connection?
3. For about a year, the indication was off, what can be the cause for it to be on now?

Thanks in advance,
Ilia

what is the voltage between 'neutral ' and 'ground' when 'reverse polarity' indicator is ON?

one possible reason is , somewhere in the wiring ' a discontinuity in ' neutral ' line.

srizbf said:

what is the voltage between 'neutral ' and 'ground' when 'reverse polarity' indicator is ON?

one possible reason is , somewhere in the wiring ' a discontinuity in ' neutral ' line.

Click to expand...

Actually I didn't measure this voltage, I will do it.

Why discontinuity in the 'neutral' can cause voltage on the 'neutral' line?

You need someone who knows what boat wiring should[\B] be like. My guess would have been that is should be fully isolated, not with a grounded neutral like house wiring, but I have no boating knowledge. The non-zero voltage indication could indicate a leakage current from one of your distribution wires. This could be from water getting in the wiring.

Keith

When using transformer, is there any reason to work with floating voltage instead of grounded neutral? (except for safety issues)

If you have a fully floating system (like they use on building sites) then you won't electrocute yourself if you touch either of the wires (but not both!). If you ground the 'neutral' then you will electrocute yourself if you touch the other one.

Keith

The European Recreation Craft Directive states that the earth should be connected to the metal hull. The earth must not be connected to neutral on the boat. Not sure how that applies to an isolation transformer though.

This might be worth a look: **broken link removed**

Boat electrics are a serious matter (obviously due to the water) and I won't give any other advise (other than be careful!) because I'm not an expert. I do know that even a low voltage leakage into the water can paralyze and drown a diver.

My idea was that when I connect isolation transformer, I'm working in a different operation mode than the boat is intended to, because if the boat was in a marine in the US, it would have worked on a 110 V directly from the shore, where the neutral is actually zero. Therefore, when connecting the neutral at the output of the transformer to the ground of the boat (that is not connected to the shore's ground when using the isolation transformer) I'll create the same situation as if there is no isolation transformer. I see different approaches online and can't decide if there is a problem in wiring it in such way…