Reverse Polarity One Sub Panel

[Thomas1985]

I have two AC panels… one with my AC and water heater is lighting up reverse polarity. The other with everything else is not.

Why is this occurring?

It did coincide with heavy AC use yesterday and I awoke to find the reverse cycle iced over. Temp dropped a lot overnight if that matters.

[Turtle Blues]

Believe it is multiple issues. What is the power feed from the dock to your vessel? Multiple or single feed? Does shutting down and reenergizing make a difference? I would check the condition of cord ends and the pins inside the connection sockets for heat damage.

The icing over, is it just ice build up? or are you saying the reversing valve changed position? Ice build up would not be that unusual, actually driving the reversing valve would be a problem.

[Thomas1985]

Just covered in ice.

[Thomas1985]

I’ll pull panel and check the connectors.

The main AC panel with everything else on it is fine. The separate AC panel that has the air conditioner on it is dead with reverse polarity lit up.

[Turtle Blues]

So the freezing is just due to extended running.


For the power issue I was focused on the visible connections. Recent heat levels have caused a lot of cord and plug connection overheating issues.
Some older systems have neutral breakers that can trip without tripping the hot leg. this can show up as a reverse. Suggest reset of all main breakers, Dockside and Panel as a first step and then checking connection points for discoloration and damage.