Reverse pol when air con in on?

[jeaneous]

This started happening after coming off the hard yesterday. I plug in to shore power, no rp light. I flip air con switch to shore power, I get rp light, but air con works. I flip inverter to
Shore power, inverter breaker trips. I turn air con switch from shore power to off, rp light is off. Now I can flip inverter to shore power.

Any thoughts?

[smac999]

Check the actual voltages at the panel. With and without load. (H-n , h-g, n-g).

A rp light coming on with load is nornally a bad/ lose neutreal. Not rp. Otherwise light would always be on.

[SailingHarmonie]

A reverse polarity light is simply a light wired from the neutral to the ground. The neutral and ground should be at (very close to) the same potential, so no light.

If the is a high resistance connection on the neutral back in the marina, then there is a voltage drop that raises the voltage of the neutral wire on the boat. If it rises high enough the light comes on.

[jeaneous]

Ok, so the air con switch is flipped to shore power. I hear a relay at the air con. Rp light turns off. I hear the relay again, rp light turns back on.

[hjohnson]

Originally Posted by jeaneous

Ok, so the air con switch is flipped to shore power. I hear a relay at the air con. Rp light turns off. I hear the relay again, rp light turns back on.

Yeah, there's a high resistance on the neutral somewhere upstream of your boat. The high current draw of your AC causes the voltage the voltage on the neutral conductor to rise high enough above the protective earth conductor that the light lights up.