Sewer Light

[sjones]

We have a new 1980 25' International, in the final stages of restoration, really enjoy the forums and all the advice. We have a sewer light on the back of our AS. I can't find a switch any where. We went on a trial run this weekend. Setting around the camp fire we noticed the sewer light was on. Don't know how it turned on. Can't turn it on now. What did we turn on to make that light on the back of the trailer work? Any suggestions?

Thanks

[A W Warn]

Are you sure what you are seeing is not a reversed polarity warning light?
Could you post a picture?

[sjones]

It is the small light on the back of the trailer about the size of your thumb, I'll try to get a picture of it tommorrow. It was hooked up to the Tow Vehicle at the time and also connected to shore power. I have tried every switch with lights on them and the water pump to see if that turned it on. I can't find a switch that is connected to this light. More curious than anything.

[wkerfoot]

I am fairly certain that it is the reverse polarity light. It only comes on when the polarity on the 120V feed is reversed.

Bill

[richinny]

does it look like this?
http://www.airforums.com/forums/f37/...his-61304.html

[idroba]

Yes, most likely the reverse polarity light. AS discontinued using it some time ago as in certain situations it can cause a shock when you touch the trailer. See zeb's response in the listed "does it look like this" post. I have one on my Argosy's and removed it from both to eliminate that shock possibility, which is very real.

[sjones]

Yup, that's the lights..thanks for the responses...

[A W Warn]

Originally Posted by idroba

Yes, most likely the reverse polarity light. AS discontinued using it some time ago as in certain situations it can cause a shock when you touch the trailer. See zeb's response in the listed "does it look like this" post. I have one on my Argosy's and removed it from both to eliminate that shock possibility, which is very real.

You did not eliminate the hazard, you eliminated being aware of the hazard.

The reverse polarity light is a warning light, a safety device, not a hazard. If it is glowing it is telling you that the polarity in the trailer is reversed because of incorrect wiring. The reversed wiring causes the shock hazard.



Two common conditions that will cause this light to glow.

1. (in the trailer) It could be if the wiring in the trailer's power cord or inside the trailer's breaker box has been changed when the end has been replaced or repaired, if the neutral and load wires are reversed
2. (in the shore power) It could be that the inside of the campground's breaker box, where the trailer is plugged in, is wired incorrectly, if the neutral and load wires are reversed.

Either of these conditions cause electricity to flow through the neutral wire to the ground wire. All metal skin and frame on the trailer are attached to the ground wire. When you stand on the earth outside the trailer and touch the trailer you complete the electric circuit to the ground from the trailer skin. The more conductive (wet) the earth is the more voltage you will receive.

If the polarity is reversed you can also get shocked through anything that is grounded inside the trailer if you touch and complete the circuit, like the water lines, stove, fridge door, or plumbing fixtures.

[idroba]

Originally Posted by A W Warn

You did not eliminate the hazard, you eliminated being aware of the hazard.

The reverse polarity light is a warning light, a safety device, not a hazard. If it is glowing it is telling you that the polarity in the trailer is reversed because of incorrect wiring. The reversed wiring causes the shock hazard.



Two common conditions that will cause this light to glow.

1. (in the trailer) It could be if the wiring in the trailer's power cord or inside the trailer's breaker box has been changed when the end has been replaced or repaired, if the neutral and load wires are reversed
2. (in the shore power) It could be that the inside of the campground's breaker box, where the trailer is plugged in, is wired incorrectly, if the neutral and load wires are reversed.

Either of these conditions cause electricity to flow through the neutral wire to the ground wire. All metal skin and frame on the trailer are attached to the ground wire. When you stand on the earth outside the trailer and touch the trailer you complete the electric circuit to the ground from the trailer skin. The more conductive (wet) the earth is the more voltage you will receive.

If the polarity is reversed you can also get shocked through anything that is grounded inside the trailer if you touch and complete the circuit, like the water lines, stove, fridge door, or plumbing fixtures.

This partial post from Zepp is the hazard and reason for my statement:

"If the RV park is wired backwards AND their ground is bad at your receptacle, the reverse polarity light will energize your shell and give you a nasty shock if you step onto wet ground while holding onto any part of the shell. Check out your wiring schematic and you'll see how that can happen.

Low probability, yes. Has it happened? Yes, at least a couple members have posted about this. The real probability is unknown, but if the person who wired the hot/neutral backwards was that inept, then not having a good ground is more likely, which makes this more like a single failure than a dual failure. By the way, when the ground is bad, the light doesn't come on, it just waits quietly to shock you."

Airstream eliminated the "polarity warning light" as it had the potential to actually cause problems, as well as making you aware of them. It also gave false security that all was OK, when it might not be due to a bad ground.

[A W Warn]

Originally Posted by idroba

"If the RV park is wired backward AND their ground is bad at your receptacle, the reverse polarity light will energize your shell and give you a nasty shock if you step onto wet ground while holding onto any part of the shell. Check out your wiring schematic and you'll see how that can happen.

The above statement is correct. But, this backward wiring and bad ground situation is the real problem, if it exists. Something plugged up or turned on in the 120v circuits inside the trailer might do the same thing. In this situation you can get shocked with the warning light installed or you can get shocked if the warning light has been removed.

Don't have a false sense of security if the reversed polarity warning light has been removed.