240v Inverter to feed 240v ship service

[CapnBazza]

Interesting problem that I haven’t been able to figure out. I have a 240v sine wave inverter which powers everything from iphone chargers to the steam and dry iron. Currently connected to shore power, everything appears functioning normally - good voltage, no reverse polarity etc. But when I feed the main board with the inverter output (extension cable from inverter socket to ship input socket) the inverse polarity warning light is on, I measure 237v between active and neutral, 173v between active and earth and 76v between earth and neutral. Anything trips the ELCB as soon as switched on. The extension cable plugged into the inverter shows no reverse polarity problem. Does anybody have any suggestions as to what the issue might be?

[smac999]

You have a floating ground inverter. Pretty common for cheap inverters. .

I don’t Know the rules there. But in North America every Mairne rated inverter has a ground to netreal bond switch that engages while inverting.

[CapnBazza]

Originally Posted by smac999

You have a floating ground inverter. Pretty common for cheap inverters. .

I don’t Know the rules there. But in North America every Mairne rated inverter has a ground to netreal bond switch that engages while inverting.

Thanks mate, I understand the floating ground but when I test the inverter output there are no reverse polarity problems and I have 237v between Live and Neutral and negligible voltage between Live and Ground or Neutral and Ground. When I plug in an appliance, all works well. What is it about a boat (perhaps just mine) that makes the boat float at different voltages? I am not surprised that the ELCB trips with readings I am getting. Is there a solution or should I just use cords plugged into the inverter (it has three sockets) when not on shore power?