Reverse polarity

Discussion in 'General Discussion' started by Jerrit1, Jan 20, 2018.

  1. Jerrit1

    Jerrit1 New Member

    6
    Dec 18, 2017
    Michigan
    1988 Sea Ray 268 Sundancer
    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.
     
  2. scoflaw

    scoflaw Well-Known Member SILVER Sponsor

    Aug 10, 2011
    cape cod mass
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    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.
     
  3. hottoddie

    hottoddie Well-Known Member

    Jan 11, 2012
    Boston/Cape Cod
    1986 Sea Ray 390 Express
    Garmin 4212 Chartplotter
    Garmin 24 HD Radar
    Garmin GSD 22 Sounder
    Garm
    454 Crusaders
    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.
     
  4. Jerrit1

    Jerrit1 New Member

    6
    Dec 18, 2017
    Michigan
    1988 Sea Ray 268 Sundancer
    Single 7.4L Mercruiser with Alpha One (Gen 1) outdrive.
    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.
     
  5. Creekwood

    Creekwood Well-Known Member GOLD Sponsor

    Apr 26, 2009
    Oakville and Georgian Bay, Ontario
    '97 330 Sundancer
    2X 454 w/ vDrives
    Good thing you found it. Not safe to have outlets not grounded properly.
     
  6. Jerrit1

    Jerrit1 New Member

    6
    Dec 18, 2017
    Michigan
    1988 Sea Ray 268 Sundancer
    Single 7.4L Mercruiser with Alpha One (Gen 1) outdrive.
    Would an open ground in my garage outlet cause a reverse polarity fault on the boats power panel?
     
  7. Jerrit1

    Jerrit1 New Member

    6
    Dec 18, 2017
    Michigan
    1988 Sea Ray 268 Sundancer
    Single 7.4L Mercruiser with Alpha One (Gen 1) outdrive.
    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.
     
  8. MickT

    MickT Member

    58
    Aug 5, 2016
    australia - newcastle
    2006 sundancer 300
    twin mercruiser 5.0 mpi w/bravo III
    Yes, needs a ground - probably also needs a MEN link at the fuse box too
     
  9. 5Weeks

    5Weeks New Member

    15
    Jul 16, 2017
    Lake Guntersville
    2002 SeaRay 360DA
    Twin Mercruiser 8.1 Horizons
     
  10. 5Weeks

    5Weeks New Member

    15
    Jul 16, 2017
    Lake Guntersville
    2002 SeaRay 360DA
    Twin Mercruiser 8.1 Horizons
    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.
     
  11. Jerrit1

    Jerrit1 New Member

    6
    Dec 18, 2017
    Michigan
    1988 Sea Ray 268 Sundancer
    Single 7.4L Mercruiser with Alpha One (Gen 1) outdrive.
    If you were to read this thread in its entirety you would see that this has already been addressed.
     
  12. wayne0

    wayne0 Member

    269
    May 4, 2014
    Newburyport, Ma.
    2000 340 Sundancer
    Twin 7.4 ltr.V-drives
    Sounds like you might have a neutral-hot reversed somewhere. Every thing will work, but "it ain't right"
     
  13. Jerrit1

    Jerrit1 New Member

    6
    Dec 18, 2017
    Michigan
    1988 Sea Ray 268 Sundancer
    Single 7.4L Mercruiser with Alpha One (Gen 1) outdrive.
    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.
     
  14. ttmott

    ttmott Well-Known Member GOLD Sponsor

    Apr 3, 2012
    Space Coast Florida
    2006 52 Sedan Bridge
    Cummins QSM11
    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.
     
  15. Westie

    Westie Active Member

    Oct 16, 2008
    Calgary
    2001 260 Sundancer towed with the power of an IFORCE V8
    7.4 L Bravo III
    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.
     
  16. ttmott

    ttmott Well-Known Member GOLD Sponsor

    Apr 3, 2012
    Space Coast Florida
    2006 52 Sedan Bridge
    Cummins QSM11
    Yes thank you!
     

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