Reverse Polarity

[Terry Forshier]

When I first brought the boat to my dock I plugged in the shore cord(s)and the "reverse polarity " lights came on. I went to the dockmaster post and reversed wires on the main supply connector and they went out. I have a splitter for two 30 amp cords. (One to the boat and one to the AC unit)Today I attempted to see if my AC unit would run with my little HONDA 2000 generator. It did run it, but the "reverse Ploarity" light came on when plugged into the generator. I then plugged the main boat shore power cord into the generator and got the same readaing on that pannel."reverse polarity"
The instructions under the light on the "board" say to disconnect immediatly if the light come on. So what is going on here? Ideas?

[Ted Pounds]

Terry,

Reverse polarity is a very dangerous situation.  There is potential for electric current to leak into the boat's grounding system electrocuting someone on the boat or in the water near it.  If you had to reverse the wires on the main supply connector initially, it sounds like your dock may be miss-wired.  My initial recommendation is to hire a good electrician to sort the whole thing out.  It may cost a few bucks, but electrocuting somebody is a lot worse.

[Mike and Joanne Stimmler]

Terry, I agree with Ted, You really need to get an electrician involved. From your discription it sounds like the dock wiring is good and your boat wiring is reversed since another source of power(your generator)shows a reverse too! Is the boat new?If you are coming from another marina, that wiring may have been reversed to wrongly correct the situation.Proceed cautiously!
Good Luck,
Mike

[Ron Hill]

Terry : I agree with Mike.  You need to get your AC wiring checked out. 
Many electronic items of equipment are VERY sensitive to polarity - you could do permanent damage to items such as battery chargers, inverters etc.   

[Stu Jackson]

Terry

You wrote: "I went to the dock-master post and reversed wires on the main supply connector..."

This sounds to me like YOU switched the hot and neutral wires yourself at the dock box, so the reverse polarity lights went out.

Then, when you used your generator, the reverse polarity came back on.

This means that there was nothing wrong with the dock box power before you switched it, because the generator showed your boat wiring to be wrong.

There is a very simple fix to this: check the wiring connection at the back of your shorepower inlet and trace it to the electrical panel.  Black is hot, white is neutral.  The black wire should go to the main AC breaker and the neutral goes to the terminal block glued to the side of the hull behind the panel.

Somewhere, someone wired those two wires backwards onboard.

Once you figure that one out, go back and switch the dock box power back to where it was to begin with.

Also check the individual outlets with an inexpensive polarity tester (only a few bucks from a hardware store -- avoid a marine store).

Also check this post where I updated the AC wiring diagram from an earlier discussion on reverse polarity which I found with a search on the word "diagram:"  http://c34.org/bbs/index.php?topic=2620.0 

This diagram is very small and hard to read unless you download it and up size it.  I'd be glad to email to anyone who is interested, email me at mraquaq@aol.com.  I'll also send it to Mark Elkin to get it posted full size on the Projects page.

This post also includes pictures of the reverse polarity lights on the 1986-era electrical panel, AC side.  We have three lights.  This link may help you.

Please let us know what you find.

[Terry Forshier]

I had an electrician come today to check this "reverse Polarity" situation. It appears that the problem was in the HONDA generator. (if it is a problem) HONDA does not have a set up putting 110 volts on one side and a ground on the other. Instead it separated the voltage into 55 volts per side. (each plug in side containing roughly half the volts needed to make the 110).
The plugs ins on the boat are fine and work ok when plugged into the shore power whether on the post or an adaptor plugged into a extension cord from the house>)
I am told that I am good to go using the HONDA 2000 to run the AC. Also I am told the Coast Guard is now frowning on people carrying portable generators on board. The main problem, being improper ventilation.
Terry in NAples

[Ron Hill]

Terry : If I were you I'd call Honda.  I've had a Honda for 3 years and have NEVER had the reverse polarity light come on. 
Think you've got something strange going on.   

[Stu Jackson]

Terry

Hmmmmm..........

The solution you described sounds VERY suspicious.

Remember what we said in the posts above?  Did you re-reverse the wiring on your dock connector???

NONE of the answers EVER questioned the generator.

I do NOT own a generator.

I DO know about electrical systems.

I think you got the WRONG answer.

PLEEEEZE  -  for your safety, reread the posts above and DO YOURSELF A FAVOR, go trace AND UNDERSTAND the wiring yourself.

There are ONLY three wires to deal with, after all.

"Good to go" is a phrase, from someone who will NOT be sailing with you,  that ALWAYS is of concern.  Easy for "them" to say...

The Coast Guard is now being known to frown upon boats having people aboard.

[Footloose]

Terry

You need to figure out what is wired backwards and as Stu said it isn't that hard.  I would get a plug in tester for  the hardware store and start at the dock out let and work to the boat.  If you don't have a 30-20 amp "converter" borrow one and plug it into the dock outlet.  If it checks out OK plug in the shore power cord.  Use the tester at each step.  These things have lights that tell you good or bad so you don't have to be an electrical engineer to use one.  Keep adding things until you find the culprit.  Also look for a bad ground.

[Terry Forshier]

The electrician is my cousin is an owner of one of the largest electrical companies in Naples. He has worked on boats for years. He will be sailing with me. We did check polarity on all the circuits and checked with the post I switched and with the feed from the house. We removed the pannel and checked those circuits. We tested using the shore power cords in all the recepticals as described above.  All were ok. The generator was checked and found to send the electricity as explained above. The HONDA 2000 IU is an inverter/generator. I do not know the big differences but it clearly sent out about 60 volts on the meter from each side of the plug in making a 110 amp outlet.
One thing we found is the little red battery switch light always stays on blinking. This light is below center on the panel. Also with the Perko switch on OFF, shore power unplugged and all circuit breakers off I was getting some electrical bleed off and showing 4 amps on the indicator. Does this mean the switch is bleeding current?
always something (Roseanna sanna danna)
Terry

[DEMERY]

I'd just like to second, that I use a Honda EU2000i generator and do not experience reverse polarity. As suggested above, I'd follow up with Honda before I'd continue to use the generator.

PS: If you're truly drawing four amps with everything turned off, you need to have your cousin come back out or another qualified electrician to correct the problem.

Good Luck,

Dave

[Stu Jackson]

Terry

Much good news, glad you're being thorough, our only concern is your health and welfare.  Good luck with gremlins and grinches!

[Phil Yates]

TERRY,
I HAVE THE SAME PROBLEM AT TIMES, ALL I HAVE EVER  DONE IS GO OUT TO THE DOCK AND REVERSE MY PLUG, AND THE RED LIGHT GOES OUT AND I HAVE THE GREEN ONE SHOWING....... HOPE I'M DOING THE RIGHT THING AS I HAVE BEEN DOING IT FOR 10 YRS WITH THE ECLIPSE..

[Terry Forshier]

I emailed a Honda rep and he agreed with our findings that there was 60 volts per side and that makes 120 V. He said it would light the reverse polarity light.( as it did)  He also said that it shouild work fine and not cause any damage.
As far as I am concerned "case closed"
Thank you all for the input.

[Ron Hill]

Terry : I know the case is closed, but I also of about a dozen Honda owners that DON"T get a reverse polarity light!!
In 1987 ABCYA changed their electrical rules and Catalina changed their wiring.  I have a single throw double pole 30 amp breaker. 
FYI - the few times that I've experienced REAL reverse polarity -  the light comes on, that breaker will trip and will NOT stay on !!!!