another Reverse Polarity light question

Charlie98117

Charlie98117

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Jul 1, 2014
262
Hunter 34 Seattle
I recently replaced the burned out 110V indicator light on my panel and after doing that the Reverse Polarity light comes on. It goes out when I turn on the 110 main breaker. The old indicator light was neon and the new one I got from Paneltronics was LED so I thought it might be LED polarity or something so I switched the connections but get the same result. Just to be sure I checked with a multi tester and confirmed the hot leg was indeed still the black wire.

I don't know how the reverse polarity detection circuitry works so I'm wondering if the LED is could be causing this or what else it could be.
 
J

JohnShannon

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Jan 4, 2010
1,037
Farr 30 San Francisco
I think the reverse polarity light is place between neutral and ground. If things are correctly wired there should be no voltage between neutral and ground. If hot and neutral are switched, then you have 120V across the lamp to gnd and it lights up. Do you have a galvanic isolator? Is the polarity lamp just as bright in both directions?

It sounds to me like things are correctly wired. When the breaker is open then the hot and neutral are floating (well mostly) it sounds like you have a little bit a leakage from i dunno what onto the neutral that is enough to light up the polarity LED but maybe not a polarity neon. When the breaker is closed, then the potentials are correct and the polarity light goes out.

So the polarity light is indicating some other issue. You could start turning off 120V loads and see if the light goes out.
 
Brian D

Brian D

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Feb 17, 2006
5,274
Lancer 27PS MCB Camp Pendleton KF6BL
On my boat, the line (hot) is the only one of the three (line-neutral-earth) that is switched so when you throw the breaker to off there might be residual voltage between the neutral-earth. It is possible that the reverse polarity indicator you installed is too sensitive. With the AC breaker off you can measure for a voltage with a DVM between the neutral-earth and see if there is a voltage. I read that anything between 0~15 vac should be acceptable. Anything above that is a problem.

IMHO
 
X

Xanthus

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Feb 9, 2015
11
Ericson E-34 Lk Champlain
The neon lamp needs a high voltage to turn on where the LED doesn't. It will light with a very small voltage which is likely available between the neutral and ground lines under normal conditions.
 
Charlie98117

Charlie98117

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Jul 1, 2014
262
Hunter 34 Seattle
Just to be clear, the bulb I replaced was the 110 V indicator, not the reverse polarity bulb. With the breaker off, the indicator light is off and the RP light is on. With the breaker on the indicator light is on and the RP light is off.
 
X

Xanthus

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Feb 9, 2015
11
Ericson E-34 Lk Champlain
Sorry I jumped to conclusions at first.
Does the RP lamp operate normally without the LED in the circuit? Is there any change if you kill your inverter? Disconnect shore power cable?
With the breaker open and the LED connected what is the voltage across the neutral to ground read with a digital meter. An analog meter may not read correctly.
 
Charlie98117

Charlie98117

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Jul 1, 2014
262
Hunter 34 Seattle
Xanthus said:
Sorry I jumped to conclusions at first.
Does the RP lamp operate normally without the LED in the circuit? Is there any change if you kill your inverter? Disconnect shore power cable?
With the breaker open and the LED connected what is the voltage across the neutral to ground read with a digital meter. An analog meter may not read correctly.
Click to expand
Good questions. The RP light does not come on until the shore power cord is plugged in, I'll have to get back with a meter to check voltage between ground and neutral. I'll snip the 110 indicator light to see if the RP light comes on when it is not in the picture. Somehow I thought the new light has to be contributing since prior to changing it I've never seen the RP light come on.
 
Charlie98117

Charlie98117

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Jul 1, 2014
262
Hunter 34 Seattle
I think the RP light is neon as are the other ‘83 bulbs so its sensitivity shouldn’t have changed. Could the LED indicator be allowing some sort of leakage the old neon bulb didn’t? I didn’t think diodes would leak.
 
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