Reverse polarity

Jerrit1

New Member
Dec 18, 2017
14
Michigan
Boat Info
1988 Sea Ray 268 Sundancer
Engines
Single 7.4L Mercruiser with Alpha One (Gen 1) outdrive.
I bought a 30amp twist on to 15amp household adapter and when i plug it into my 1988 Sundancer 268 I get the reverse polarity light on the power panel.
Do these adapters come in different polarity options or is my whole garage wired wrong?

I am running an extension cord from my garage wall outlet to the adapter --> boat.
 
You got a bad connection, try spreading the prongs a bit. Use a short heavy cord.
Turn off all your boat breakers and fire them up 1 at a time.
 
I would start by checking the polarity at the outlet first. You can buy very inexpensive polarity testers at HD. You can also Google how to test for polarity.
 
I went to the hardware store and bought a polarity checker and it says i have an open ground at my garage outlet.

The boat already had all switches to off including the main switch.

I dont know if this mattets but the boat has no batteries in it now.
 
Good thing you found it. Not safe to have outlets not grounded properly.
 
Would an open ground in my garage outlet cause a reverse polarity fault on the boats power panel?
 
OK, more info found, after talking to an electrician friend we determined my outlets in my (1950's built) garage don't need to be grounded per code since they are all protected GFCI outlets. So my question still is "Would an open ground in my garage outlet cause a reverse polarity fault on the boats power panel?" ...he seems to think it should not but he is not a boat owner, if that matters. Thanks.
 
I bought a 30amp twist on to 15amp household adapter and when i plug it into my 1988 Sundancer 268 I get the reverse polarity light on the power panel.
Do these adapters come in different polarity options or is my whole garage wired wrong?

I am running an extension cord from my garage wall outlet to the adapter --> boat.
 
I have seen house receptacles wired incorrectly. That was an issue on one of my home inspections I had to correct before selling. Plug will still work too. You can buy a cheap tester that plugs in the receptacle.
 
I have seen house receptacles wired incorrectly. That was an issue on one of my home inspections I had to correct before selling. Plug will still work too. You can buy a cheap tester that plugs in the receptacle.
If you were to read this thread in its entirety you would see that this has already been addressed.
 
Sounds like you might have a neutral-hot reversed somewhere. Every thing will work, but "it ain't right"
 
I had an electrician friend look at it, no "neutral hot reversed" anywhere, just a couple outlets not properly grounded but its all been fixed. Should have a warm (45 deg F) weekend so ill try out the garage outlet to extension cord to adapter to boat then.
 
The reversed polarity light is simply a lamp connected between the boat's neutral and the boat's ground. As in most home's (or the marina's) main disconnect panel the neutrals are bonded to the ground there is then very little current difference between the neutral and ground conductors. Sometimes the lamp will flash a bit which is caused by high current on the neutral (a lot of devices running on your boat) and the resistance difference in the wire length between where the neutral and grounds are bonded together. Obviously then, if the hot and neutrals are reversed the reverse polarity light will illuminate. Now, if you don't have the boat's ground system tied to your power source as described then the neutral is providing current through the lamp to an alternant ground path and the lamp will illuminate. You should get a proper three wire path installed for safety sake.
 
The reversed polarity light is simply a lamp connected between the boat's neutral and the boat's ground. As in most home's (or the marina's) main disconnect panel the neutrals are bonded to the ground there is then very little current difference between the neutral and ground conductors......

Just want to correct this statement. I suspect it was a typo on your part but don't want anyone else to see this and assume it is correct.

You should have said there is very little VOLTAGE difference between the neutral and ground conductors.

There is a large difference between the CURRENT in the neutral and ground conductors. In a properly wired system there is no current in the ground conductor, all the current will be in the neutral and the line (hot) conductors.
 
Just want to correct this statement. I suspect it was a typo on your part but don't want anyone else to see this and assume it is correct.

You should have said there is very little VOLTAGE difference between the neutral and ground conductors.

There is a large difference between the CURRENT in the neutral and ground conductors. In a properly wired system there is no current in the ground conductor, all the current will be in the neutral and the line (hot) conductors.
Yes thank you!
 

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