Northern Lights Genny, reverse polarity ?

I have Northern lights genny with 1100 hrs on it. This past weekend when I started it up as we were leaving the dock the reverse polarity light came on. A few of my GFCI outlets started popping. I turned the genny off, checked some things, turned on the inverter to see if the 120 vac system was ok and it worked as normal. Started the genny and the fault occurred still.

We waited about :30 and started the genny again and everything seemed fine now ? I have had no changes to any part of the system, no new wiring or circuits. Any ideas ?

I would be checking the transfer switch. That's the only thing that would have changed.

The reverse polarity light compares voltage on the neutral side of your distribution panel and the green ground. You have a lot of inspecting to do because it's intermittent.
Question, were all of the gfci receptacles that tripped have something plugged in and in use?

Archie:
The GFCI outlets that tripped did NOT have items plugged into them.
One in the Galley I was able to "reset" by pressing the reset button, the outlet in the forward cabin would not reset and kept popping (red light on the outlet stayed on).
I plugged in a little yellow circuit tester into each outlet and the illuminated lights indicated reverse polarity as well.

I would guess the problem is related to the forward cabin circuit. If not, then the transfer switches, or the generator leads box. Make sure shore power, generator, and the inverter are de-energized!!!

I wonder if you've lost your ground to the generator?

Check that neutral and gnd are tied together in the gennie control box. The should be.

I am betting you have a loose neutral connection. GFIs are popping because the ground is carrying current causing an imbalance between the hot and neutral. If it does not happen using shore power then the problem is isolated between the transfer switch and generator or the transfer switch itself.

You may actually have visual evidence if it has been happening for a while. When you go looking the cabling insulation may be discolored from running hot. Check all the easy places first but you really need to go from beginning to end and also consider checking and tightening the other AC electrical connections as a precaution.

TJM said:

I have Northern lights genny with 1100 hrs on it. This past weekend when I started it up as we were leaving the dock the reverse polarity light came on. A few of my GFCI outlets started popping. I turned the genny off, checked some things, turned on the inverter to see if the 120 vac system was ok and it worked as normal. Started the genny and the fault occurred still.

We waited about :30 and started the genny again and everything seemed fine now ? I have had no changes to any part of the system, no new wiring or circuits. Any ideas ?

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Ski is correct about this too. You can prove it is easily with a plug in three light tester with the GFI check button. When you are using the generator as the power source a three light tester will not trip GFIs if the neutral is not grounded. When initially plugged in you will get the normal two yellow lights but when you hit the GFI test button all the lights will come on and the fixture will not trip.

The reason a tester will not trip GFIs if the neutral is not grounded at the power source is the tester creates a fault using the ground path. No path no trip. The GFI outlets themselves measure imbalances between the hot and neutral whether a ground is present or not. If an imbalance occurs they trip.

Ski in NC said:

Check that neutral and gnd are tied together in the gennie control box. The should be.

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Excellent advice. Through all of the explanations I feel much more confident to diagnose tonight when I return to the boat.