400 SB- 30amp-to 50amp

Discussion in 'Electrical Stuff' started by Ray 40, Jun 7, 2009.

  1. The Bill Collector

    The Bill Collector Well-Known Member GOLD Sponsor

    Jun 2, 2008
    Tacoma, WA
    1998 450 Sundancer, Achilles dinghy w/15hp
    3126 Cat's
    Gentlemen, you are entitled to your opinion. Any further debate you can have with Marinco.

    Below is a reply from Marinco Marine Electrical.......


    Thank you for contacting us about the shore power pigtail adapters. The appropriate one for your application would be our part number # 110A (see attached). We do not sell direct, but these should be available through most marine dealers and online retailers.

    There shouldn't be any concerns with these products since they do not allow the dock receptacle to force too much power into your boat. They simply allow the boat to pull what it needs from the dock and the breaker on the boat would trip if too much power was drawn.


    Let us know if we can be of further assistance.

    Regards,

    David Colclough
    Technical Support
    Marinco Electrical Group
    technical@marinco.com
    (707) 226-9600 x298
     
  2. Sea Gull

    Sea Gull Well-Known Member

    Oct 19, 2006
    CT
    2019 Maritimo M64
    Volvo D13-1000
    The Bill Collector: It really is bad advice. It may be something you would do, but to publish it on an open forum as the answer to this problem is irresponsible.

    A breaker can only trip if there is a problem downstream. If a short develops in the wiring upstream of the ship's 30 amp breaker there could be issues. Is it likely? No. Are parts available to do it? Yes. But there is a right way and wrong way here and Frank x 2 are right about this one.
     
  3. fc3

    fc3 Just another eclectic geek TECHNICAL Contributor

    Nov 12, 2006
    Northern NJ
    1999 Sea Ray 330DA
    Twin 7.4 MPI (310 propshaft HP) V-drives
    Twin Mercury Marine marinized 7.4L L-29 V8s
    Cast iron block w 4-bolt mains
    National Electric Code.
     
  4. fwebster

    fwebster Well-Known Member TECHNICAL Contributor PLATINUM Sponsor

    Oct 6, 2006
    Middle Tennessee ; Panama City Beach, FL
    1996 450DA
    3116 Caterpillars
    Guys,

    The real problem here is that you have an area of the circuit that is unprotected by the boat's electrical system............all the wiring between the recepticle on the dock and the main power panel on the boat is only protected by the power pedestal breaker on the dock. If you are supplying a 30A entrance with a 50A shore service, then your 30A shore power cord, your 30A inlet on the boat and your wiring between the boat's inlet and the main panel breaker can be exposed to 60% higher loads than they are designed for.............irrespective of what Mr. Technical Support guy @ Marinaco says.
     
  5. PMC

    PMC Well-Known Member

    Apr 10, 2009
    Long Island, NY
    2001 40 Sedan Bridge
    Cummins 6CTA
    I see this as a similar equivalent

    In your home, you cannot change swap a 15 amp breaker with a 20A without first updating the wiring. The potential load throughout the thinner cable is simply not safe. Very bad will eventually happen!!!

    What is the recommendation for this? Is there a proper cable that has some sort of breaker or fuse that would blow @30Amps?
     
  6. earthmover17

    earthmover17 New Member

    706
    Jan 3, 2008
    land o lakes florida
    560 sedan bridge
    cat 3196
    Bottom line, He could use the pigtail adapter but the breaker in the pedestal MUST BE CHANGED TO A 30 amp breaker.
    That would be the only truly safe way to do it.
    Jack
     
  7. Hampton

    Hampton Air Defense Dept TECHNICAL Contributor

    Nov 26, 2006
    Panama City, Fl
    2008 44 Sedan Bridge
    Cummins QSC-500's
    Straight Drives
    Help educate me, please. What is it about the splitter, # 152AY, that protects me when I split 50A to two 30's too?
     
  8. boatmailster

    boatmailster Well-Known Member

    May 13, 2007
    NY
    none to share
    none to share
    I do understand that you probably thinking worst case scenario when main breaker on distribution pane fails and welds itself, but when failure occurs even 5A faulty in-line fuse holder can cause fire on boat, or lightning can strike.
    What about scenario: 30A pole service (with faulty breaker - those are outside all the time) and 30A main distribution panel with also faulty breaker. It is almost impossible to make it failure free - it is just bad luck
     
  9. Westie

    Westie Active Member

    Oct 16, 2008
    Calgary
    2001 260 Sundancer towed with the power of an IFORCE V8
    7.4 L Bravo III
    No I’m thinking of a case where because of corrosion or chaffing a wire between the shore power connection on your boat and the main panel causes a fault. Now that wire is only designed to handle 30 amps but it is being protected by a 30 amp breaker. What happens to this wire? It heats up and eventually causes a fire. Some will say “but if you have a short it will draw more than 50 amps and trip the breaker”. But most issues with wiring do not cause a direct short but a low impedance path which may not be enough to cause the breaker to trip.

    Or how about someone drops something on your 30 amp shore power cord causing an issue with it. Again you have 30 amp rated wire being protected with a 50 amp breaker.

    The properly sized breaker is there to provide a level of protection against conditions that can and do occur.

    The bottom line is: trying to protect a wire rated for 30 amps with a 50 amp breaker or fuse is unsafe and just plain foolish.
     
  10. fwebster

    fwebster Well-Known Member TECHNICAL Contributor PLATINUM Sponsor

    Oct 6, 2006
    Middle Tennessee ; Panama City Beach, FL
    1996 450DA
    3116 Caterpillars
    John,

    Nothing wrong with a splitter.......go to it!





    This discussion if full of what ifs, but here is the most likely scenario for a problem:

    In the 90's to early 2000's Sea Ray had some problems with the wiring on the power inlets and on the main panels. Whoever stripped the wire ends on the wiring harnesses did not strip enough insulation or perhaps the wires were inserted too far, but the wire lugs on some Marinco entrance fixtures and on some main panel main breakers were tightened down on insulated wire or on partially insulated wire. This worked a while, but after some useage, the increased resistance caused the connections get hot and the insulation burned away leaving a loose lug holding the wire. I've seen this happen on 400DB's (the boat owned by the original poster), on 400DA's, on 410DA's on 450DA's.....all boats with 2-30A inlets. With 30A, it usually burned up the inlet fixture, the wire between the inlet and the main panel and the end on the cord set. Several boats required fiberglass repairs to remove the damaged area around the Marinco inlet.

    This is the section of the boat's 120V wiring I described earlier that is not protected by an onboard breaker. I don't even want to think about the damage 50A would have caused..................
     
    Last edited: Jun 8, 2009
  11. Hampton

    Hampton Air Defense Dept TECHNICAL Contributor

    Nov 26, 2006
    Panama City, Fl
    2008 44 Sedan Bridge
    Cummins QSC-500's
    Straight Drives
    Frank,

    I have been using one, just trying to understand the electrical circuitry that makes it work.
     
  12. mistercomputerman

    mistercomputerman Active Member

    Jan 6, 2008
    Virginia Beach, VA
    410 Sundancer - 2001
    Twin 8.1L Mercruisers - 2009
    OK guys, help me understand this.

    I have a 50amp breaker on the dock pedestal. I have a Marinco 152AY adapter that splits the 50 amp service into two 30amp connectors. I have a boat with two 30amp shore power cords that I plug into the 152AY.

    Am I to understand that the 152AY is sending 50amps down each leg of the 152AY splitter to each of my respective 30 amp cords? And if that be the case, I am sending 50amps down each of my 30amp shore power cords all the way to the boat? And if THAT be the case, I have a 2001 boat where some bozo at Sea Ray might not have wired the Marinco inlet properly so said configuration may catch the boat on fire?

    And the solution (if I want to use the 152AY splitter) is to have the marina install a 30amp breaker on the pedestal?
     
  13. fc3

    fc3 Just another eclectic geek TECHNICAL Contributor

    Nov 12, 2006
    Northern NJ
    1999 Sea Ray 330DA
    Twin 7.4 MPI (310 propshaft HP) V-drives
    Twin Mercury Marine marinized 7.4L L-29 V8s
    Cast iron block w 4-bolt mains
    Almost there. Rick. Think of a firehose. You don't send 50A of current down the wire you just make it available. But if something allows sucking 50A of current, the breaker will allow it. Too bad the wiring will only carry 30A safely without overheating.

    Best regards,
    Frank
     
  14. mistercomputerman

    mistercomputerman Active Member

    Jan 6, 2008
    Virginia Beach, VA
    410 Sundancer - 2001
    Twin 8.1L Mercruisers - 2009
    Thank you Mr. Frank.

    I have a grip on it now. Guess I'll double check the power pedestal to see if I have a 50amp breaker or a 30amp breaker.

    What's the best way to keep from burning my boat or the Farley State Marina to the ground on July 4th while delivering twin 30amps to the boat?
     
  15. fwebster

    fwebster Well-Known Member TECHNICAL Contributor PLATINUM Sponsor

    Oct 6, 2006
    Middle Tennessee ; Panama City Beach, FL
    1996 450DA
    3116 Caterpillars
    Wait........

    If you are using the 152AY splitter, it separates the legs on your 240V 50A service and supplies 120V 25A to each of your power cords......that approach is perfectly safe.
     
  16. Hampton

    Hampton Air Defense Dept TECHNICAL Contributor

    Nov 26, 2006
    Panama City, Fl
    2008 44 Sedan Bridge
    Cummins QSC-500's
    Straight Drives

    Frank (FC3),

    I'm getting the impression that this is not the case. If so, why would it be safe to use a 152AY and not the 115?
     
  17. Hampton

    Hampton Air Defense Dept TECHNICAL Contributor

    Nov 26, 2006
    Panama City, Fl
    2008 44 Sedan Bridge
    Cummins QSC-500's
    Straight Drives
    OK - there is our answer. Simultaneous postings. Thanks again, Frank W.
     
  18. Westie

    Westie Active Member

    Oct 16, 2008
    Calgary
    2001 260 Sundancer towed with the power of an IFORCE V8
    7.4 L Bravo III
    Not true.

    You get 120 V 50 amp on each circuit.
     
  19. elreyos

    elreyos New Member

    179
    May 5, 2007
    Lake Mead
    2002 510DA
    3196 CAT
    I agree with fwebster. Take a look at your pedestal. If it's wired correctly it will have two 2 25amp breakers. One for the A feed(120v) and one for the B feed(120v). All the adapter does is split the feeds into two 120v feeds. Shouldn't be problem. If any thing draws more than 25amps on either leg the matching breaker will open.
     
  20. 1stSeaRay

    1stSeaRay New Member

    375
    Aug 25, 2008
    Lake Lanier, GA
    boatless
    boatless

    If you are correct then that would be a 25A 240V service and this entire debate is moot.

    If we are indeed talking about a 25A 240V service, with a 3 Pole, 4 wire connector, consider the following:

    As stated above the splitter separates the 2 hot legs (one for each outlet), and the ground and neutral are common
    50A Socket: (L1 - L2 - N - G)
    Outlet 1: (L1 - N - G)
    Outlet 2: (L2 - N - G)

    In the adapter, the second hot leg is not used
    50A Socket: (L1 - L2 - N - G)
    Outlet 1: (L1 - N - G)
    L2 is unused!

    So, this means that the maximum power available at the 30A outlet would be 25A.


    That said, I suspect your marina has installed 25A breakers with a 50A connector, likely as a cost saving measure in construction (25A breakers and wire are cheaper) and to limit the amount of power drawn by a single vessel. (figure they don't want you running all your appliances all the time on their dime)

    So, in the case of 25A breakers, both the adapters and splitter would both be considered "safe", however being that it is a 50A connector being used, it is possible that the OP may be in a marina that has 50A breakers installed, which would then make both "unsafe".
     
    Last edited: Jun 9, 2009

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