Reverse Polarity when hooked to shore power

LimpetMine

LimpetMine

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2002 Grady White Express 33 reverse polarity

Has anyone had any experience with the reverse polarity light coming on the AC panel?

I have tried several different shore power locations and tried different shore power cables. I removed and inspected the shore power inlet on the boat for obvious scorching etc, looks clean. I removed the 30a breaker box under the gunwale to inspect, looks good. That is as far as I went taking things apart looking for scorching.

The symptom is as follows: after plugging into shore power, the voltage meter on the AC side of the panel reads 110v with only the shore power breaker on the "on" position. At this time there is no reverse polarity light.

If I turn on any of the other breakers (battery charger, etc.) the main breaker immediately trips, and the reverse polarity light comes on.

Anyway, I'll have an electrician look at it, but was wondering if anyone had a similar experience and if they had a common issue that was identified to resolve.

This boat is new to me, and very clean, no extra wiring except for the MFD plotter/fishfinder and a small bluesea fuse block.

Thanks![album][/album]
 
LimpetMine said:
2002 Grady White Express 33 reverse polarity

Has anyone had any experience with the reverse polarity light coming on the AC panel?

I have tried several different shore power locations and tried different shore power cables. I removed and inspected the shore power inlet on the boat for obvious scorching etc, looks clean. I removed the 30a breaker box under the gunwale to inspect, looks good. That is as far as I went taking things apart looking for scorching.

The symptom is as follows: after plugging into shore power, the voltage meter on the AC side of the panel reads 110v with only the shore power breaker on the "on" position. At this time there is no reverse polarity light.

If I turn on any of the other breakers (battery charger, etc.) the main breaker immediately trips, and the reverse polarity light comes on.

Anyway, I'll have an electrician look at it, but was wondering if anyone had a similar experience and if they had a common issue that was identified to resolve.

This boat is new to me, and very clean, no extra wiring except for the MFD plotter/fishfinder and a small bluesea fuse block.

Thanks![album][/album]
Click to expand...
 
Although it is possible for a breaker problem or wiring issue in the boat to cause a false 'reverse polarity' alarm, the first place you have to look in the actual power source, the outlet you are plugging into. It may be wired in reverse with respect to line and neutral or the neutral and ground may be swapped. An electrician can easily check that
 
My electrician verified that the shore power and cable are good to go. Something on the boat...
 
My boat DOES have a galvanic isolator, I am suspicious of it as well...
 
The isolator is for your ground wire.

Something has the hot wire swapped with neutral. That is what the reverse polarity is indicating.
Try turning AC devices on one at a time to isolate the culprit.
 
There was a bad breaker in the breaker panel leaking current to the neutral. Replaced the breaker and all is good again!
 
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