Reverse Polarity Light came on?

danielgoldberg · #1 (**permalink**) 08-21-2009

L'll help.

We're on a mooring in Huntington running the genset to charge batts, heat water, etc. All of the sudden the reverse polarity light comes on. We actually have two AC banks, one for the house and one for the air conditioning (no sneers please). The reverse polarity light is on for both. It's sort of odd (at least to me), but the light is sort of "just" on, so to speak, meaning it is not very bright, but gets brighter if we put an AC load on that circuit.

I'm not tied to shore, so I don't know if I have the same issue when on shore power, though I was plugged in last night at my home dock and I don't remember seeing the RP lights on.

Any quick thoughts on how to find and fix the problem?

danielgoldberg · #2 (**permalink**) 08-21-2009

The light does NOT come on when using the inverter for AC power, FWIW.

CharlieCobra · #3 (**permalink**) 08-21-2009

Check your ground at the plug. Loose connections can cause it. The last time I got a RP signal, the circuit shorted and burned through a wire. It did throw the breaker though.

danielgoldberg · #4 (**permalink**) 08-22-2009

New facts, for those following along and for those who might have some insight:

1. RP light does NOT come on when using the inverter or shore power. So, the problem is when getting power from the genset only.

2. Using a plug-in polarity tester, I checked the polarity of all the outlets when under genset, shore power and inverter, and they all are fine (polarity not reversed, and neither ground nor neutral is open).

3. The individual circuits turn off and power off when I throw the breakers for them (outlets, water heater, AC and battery charger), so I really don't think the problem is a reversed wire somewhere.

4. The RP light, when on, is very faint and you can't really discern it in daylight unless you cup your hands over it. Um,

(sheepish grin), it is possible that this has been going on since we took delivery of the boat and we just didn't notice because it's so hard to see. I noticed it yesterday because we were using the generator after dark, which we normally don't do.

From the above, I conclude that either (1) I have no problem (some learned folks have written that a faint RP light may not be an indicator of a problem depending on how the charging source is wired), or (2) I have a loose or bad neutral or ground wire somewhere in the genset line between the switch choosing between shore/off/gen and the generator itself. I've looked and I can't find anything, but I don't feel all that comfortable dealing with A/C issues, so I'm going to have an electrician check it out Monday morning. I always wanted to spend a few days in Huntington anyway.

danielgoldberg · #5 (**permalink**) 08-23-2009

So I guess folks don't care about RP. Let me try this. Ignore this post.

badsanta · #6 (**permalink**) 08-23-2009

I have see the same thing on Island Packet boats. It is described as a faint glow in the RP light only when the gen set is running. It is considered NORMAL on there boats and a result of a slight back feed of the gen set. Has this ever happened before? is this new? I have no testing advice for you and have never experienced this myself. I am only passing along what I have heard. Sorry to be so vague.

JohnRPollard · #7 (**permalink**) 08-23-2009

Quote:

Originally Posted by badsanta

I have see the same thing on Island Packet boats. It is described as a faint glow in the RP light only when the gen set is running. It is considered NORMAL on there boats and a result of a slight back feed of the gen set. Has this ever happened before? is this new? I have no testing advice for you and have never experienced this myself. I am only passing along what I have heard. Sorry to be so vague.

That's interesting. It sounds very similar to the situation Daniel is describing.

Daniel, I don't have much knowledge about RP issues (only that if the RP light comes on, something's wrong

). All I was going to offer was that I have noticed on our boat that the RP light sometimes catches some of the glow from the battery meter backlight. So I was going to ask if there's any chance it is being faintly illuminated by another light somewhere behind your panel? Shot in the dark...

danielgoldberg · #8 (**permalink**) 08-23-2009

Quote:

Originally Posted by JohnRPollard

That's interesting. It sounds very similar to the situation Daniel is describing.

Daniel, I don't have much knowledge about RP issues (only that if the RP light comes on, something's wrong

). All I was going to offer was that I have noticed on our boat that the RP light sometimes catches some of the glow from the battery meter backlight. So I was going to ask if there's any chance it is being faintly illuminated by another light somewhere behind your panel? Shot in the dark...

Thanks John. I sure hope you know I was joking re: complaining about a lack of responses.

Anyway, I had thought of the backlight possibility, but that's not it. When you compare the difference between the light when using shore power v. generator, there's no doubt I'm getting some light when the genset is running. Too bad too, obviously. My situation is very much like the one you quoted, and I suspect my circumstance is the same. Nevertheless, I'm having an electrician look at the boat tomorrow morning, so we'll see what he says.

Thanks for ignoring.

ronbo1 · #9 (**permalink**) 08-26-2009

Dan,

So what did the electrician find?

Ronbo

danielgoldberg · #10 (**permalink**) 08-31-2009

Quote:

Originally Posted by ronbo1

Dan,

So what did the electrician find?

Ronbo

Nuttin'. I'm having the guy who did the genset install via the dealer come take a look. We'll see.