Reverse Polarity light on Scheiber panel

Apr 14, 2010
195
Jeanneau 42DS Larnaca Marina
The reverse polarity panel light is on. This usually means that the hot and neutral wires are reversed so I reversed the hot and neutral wires on my dock power extension cord thinking it should solve the problem if the dock supply has reversed polarity. The RP light is still on. Anyone has any ideas?
Lee
 
May 1, 2011
4,189
Pearson 37 Lusby MD
This happens to me periodically, and is usually because I didn't get the plug into the pedestal on the dock quite right.
 
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Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
The reverse polarity panel light is on. This usually means that the hot and neutral wires are reversed so I reversed the hot and neutral wires on my dock power extension cord thinking it should solve the problem if the dock supply has reversed polarity. The RP light is still on. Anyone has any ideas?
Lee
You can get a circuit tester for 30-amp outlet. Like the 110 volts version. maybe SBO has them?
 
May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
Actually it means hot and neutral reversed or the neutral is sufficiently above ground to light the led.
 
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Jan 19, 2010
12,362
Hobie 16 & Rhodes 22 Skeeter Charleston
I have a tester like this...


You can get them at Lowes or Home Despot. It will tell you what sort of problem you are having. Very easy to use and easy to interpret the data.
 
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DougM

.
Jul 24, 2005
2,242
Beneteau 323 Manistee, MI
I have a tester like this...


You can get them at Lowes or Home Despot. It will tell you what sort of problem you are having. Very easy to use and easy to interpret the data.
Those are good for telling what the problem is...Won’t help determine the cause.
I had a hot/neutral reverse indication on one circuit in my house and still have not been able to track it down. Oddly, nothing has been changed on that circuit in 20 years except maybe a light bulb.
 
Jul 12, 2011
1,165
Leopard 40 Jupiter, Florida
This happens to me periodically, and is usually because I didn't get the plug into the pedestal on the dock quite right.
I had the same problem when using an 30-amp to 20-amp adapter to plug my battery charger into a normal extension cord when she's on the hard. Turns out the adapter was not fully turned / seated to the boat terminal, so something was not fully engaged, causing the reverse-polarity fault. Those 1920's-era connectors are absolutely terrible for bad connections.
 
Jul 12, 2011
1,165
Leopard 40 Jupiter, Florida
Not to hijack, but the SmartPlug is on my Christmas list and will be installed before launch. Not happy that they removed the thermostat as an extra safety feature, but I'll put one in anyway. I love buying gifts for the girlfriend!
 
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Apr 14, 2010
195
Jeanneau 42DS Larnaca Marina
Not to hijack, but the SmartPlug is on my Christmas list and will be installed before launch. Not happy that they removed the thermostat as an extra safety feature, but I'll put one in anyway. I love buying gifts for the girlfriend!
What's a smart plug??
 
Oct 26, 2010
1,883
Hunter 40.5 Beaufort, SC
Clean/sand the connection spades on your shore power cord very well. I had a dim reverse polarity light and that cured it. Try the simple things first. However, a +1 for the smart plug. Just wish marina's would have the shore side smart plug too.
 
Oct 22, 2014
20,993
CAL 35 Cruiser #21 moored EVERETT WA
@Lee Hadjiosif it is a piece of wizardry developed in the Pacific NW to keep you safe on your boat while plugged into shore power...

https://smartplug.com/our-shore-power-features-are-sure-to-impress/
Here is a unbiased review of the fire risk that is inherent in the design of the the old plug design.
https://marinehowto.com/shore-power-cords-smartplug-vs-1938/
You can find them sold here on SBO to help fund these forum pages...
https://shop.sailboatowners.com/search.php?brand=sailboat&kw=smart+plug
 
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Apr 14, 2010
195
Jeanneau 42DS Larnaca Marina
It is a new type of hair plug that connects your brain directly to the internet.



or this....

View attachment 158190
Thanks for the response but I was really looking for a more technical answer than a pic! Is it the same as the three-light fault diagnostic plug sold everywhere for household outlet testing? That's not so smart and was around for over 30 years. Does the smart plug tell you why your polarity light is on? I checked the boat outlets and the hole to the right (with the ground up) is the HOT which is how it should be but the panel RP light still shines very bright!
 
Last edited:
May 17, 2004
5,028
Beneteau Oceanis 37 Havre de Grace
Thanks for the response but I was really looking for a more technical answer than a pic! Is it the same as the three-light fault diagnostic plug sold everywhere for household outlet testing? That's not so smart and was around for over 30 years.
No, it's not for testing, it replaces the shore power connection to the boat. It overcomes many of the design problems of the traditional twist and lock style plug. Check the links in jssailem's post for more info.
 
May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
What is the voltage (both AC & DC)
neutral to. Ground
Neutral to hot
Hot to ground

Find those three voltages and we can tell you why the light is on.

@rgranger those plugs assume no DC is present on the line. This might be a bad assumption on a boat.
 
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May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
@Lee Hadjiosif you also should check your power cord is pin correct (you said you reversed hot & neutral in post 1 above). if the reverse is at the marina end it will be fine at your dock but cause big problems when you dock elsewhere. If the problem is in your boat wiring then loaning you cable to someone else would be a problem

I think you’ll find there is a big DC component on one of the lines. This can be your “fault” or some one else in the marina. To check see if the DC voltage is on you power cord when not plugged into your boat.

Don’t delay on this, you could be eating up your prop, thru hulls, shaft.....

Galvanic Issolators help your boat be isolated from power issues like this.

Les
 
Jan 19, 2010
12,362
Hobie 16 & Rhodes 22 Skeeter Charleston
What is the voltage (both AC & DC)
neutral to. Ground
Neutral to hot
Hot to ground

Find those three voltages and we can tell you why the light is on.

@rgranger those plugs assume no DC is present on the line. This might be a bad assumption on a boat.
Thanks @LeslieTroyer

I had overlooked that point. You are right, of course. In a former life, I was the HAZMAT/Lab inspector at work and one of my regular tasks was to check all of the outlets in the labs once each year. I used a plug like the one above. But that was a true AC only circuit.
 
Apr 14, 2010
195
Jeanneau 42DS Larnaca Marina
The reverse polarity panel light is on. This usually means that the hot and neutral wires are reversed so I reversed the hot and neutral wires on my dock power extension cord thinking it should solve the problem if the dock supply has reversed polarity. The RP light is still on. Anyone has any ideas?
Lee
The problem is finally solved!! I first had the marina electrician verify that the dock was providing me with the right polarity. After that was verified, I took apart the power entry point setup on the boat which included an updated connection with new breakers with Ground Fault protection. And what do you know...the hot and neutral wires were reversed at the female receptacle. I quickly reversed the wires and walla...the Reverse Polarity light went out. Which proves my theory that 90% of the effort is to identify the problem, and 10% to solve it.