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6 AWG wire melt down

Discussion in 'Technical Discussion' started by Pascal, Jul 16, 2021.

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  1. Capt J

    Capt J Senior Member

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    Maybe you had a brown out on the shorepower and voltage dropped and you started drawing a lot of amps too fast for the breaker to trip. #4 wire is safer anyways.
  2. d_meister

    d_meister Senior Member

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    It could be that some strands inside the group broke when the extreme bend was made. When needing to shape heavy cable in tight spaces or areas where space is a problem, it is best to leave the cable long and then shape the bend before cutting and fitting a terminal. After bending a turn, it's interesting to see how different the lengths of strands are at the bitter end.
    There's a lot of science on current conducting capability of stranded wire. A great deal of the current is passed from strand to strand laid alongside. Think in terms of the conducting taking place from the terminal to the outer strands.
    Welding cable is famous for it's supple nature compared to battery cable, but that is because the strands are not continuous. Just a lot of shorter lengths laid alongside like bricks, only longer and bundled by insulation. Yes, the rubber is also more supple than Vinyl covering, before anyone protests.
  3. SplashFl

    SplashFl Active Member

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    The ABYC E-11 standard is quite clear that “solder shall not be the sole means of electrical connection”. Crimp and then solder yes. Straight solder. NO.
  4. Slimshady

    Slimshady Senior Member

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    I wasn't saying to solder the connections on a vessel, I'm acutely aware of the reasons not to do so. I'm simply responding that the least resistive connection is solder.
  5. mapism

    mapism Senior Member

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    I keep learning something new on US electrical components.
    Here you could only find that connected to a terminal strip (hence my suggestion of heat dissipation on that side), 'cause breakers are designed to take the bare wire directly.
  6. Capt Ralph

    Capt Ralph Senior Member

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    Stepped in What??
  7. mapism

    mapism Senior Member

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  8. Pascal

    Pascal Senior Member

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    Some US builders use similar breakers. Lazzara for one used Merlin Gerin breakers
  9. Capt Ralph

    Capt Ralph Senior Member

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    Many years ago I found a few of these mounted on a Din Rail.
    One went to the ships A/C pump.
    It was a nice installation and I thought it was a cheap fix added after factory.

    It was Hidden behind a beautiful and proper breaker panel in a Viking Sport Yacht (Princess).

    Now you show me the same, reflecting a tude that this is a normal marine breaker?

    Oh gad I need to retire from this madness,,,,
    Oh wait,, I did!!
  10. SplashFl

    SplashFl Active Member

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    All of the breakers in my last Bertram had wires screwed or pressed on from crimps. Never had a problem with any of them in 42 years of ownership but a number of breakers had to be replaced. Have you put an amp probe on the wire ?
  11. Pascal

    Pascal Senior Member

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    I have digital amp/volt/freq meters on the panel visible from the salon and helm so I know how many amps it s pulling. Typically during the day with both chillers running I m pulling about 45 amps total .

    Loads are pretty well balanced since the chillers are 240v, about 33 amps with the 240v pumps. The rest of the loads are split equally between 2 120v subpanels.

    As mentioned all the wiring and breakers are about 4 years old
  12. SplashFl

    SplashFl Active Member

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    How many amps the breaker rated ?
  13. Pascal

    Pascal Senior Member

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    As I said it s a 120/240- 50amp shore power. Dockside breaker is 50 amp and so is the breaker on the panel to which this wire is attached to.
  14. mapism

    mapism Senior Member

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    Well, I've seen boats built with breakers like these 30+ years ago and still working with all the original ones as I'm writing.
    I'm not reflecting anything, though. You asked, I replied.

    Besides, you recently posted in another thread an impressive list of breakers faults that you are used to live with, which I never heard of before - and some of them would trigger penal responsibilities for the component producer on this side of the pond, BTW.
    So... Your point is, exactly?
  15. mapism

    mapism Senior Member

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    Interesting.
    Obviously neither Lazzara nor the builder of my own tub asked CR approval... :)
    [​IMG]
  16. v10builder1

    v10builder1 Senior Member

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    Pascal,

    You are overloading the circuit. Google the 80% rule for an explanation. The continuous load for a 50 amp circuit should not exceed 40 amps. To your credit, you know what the actual load is. Many boaters have no idea. This overload contributed to the problem you cited, but the crimp was probably loose anyway - solder solidified after cooling and made the crimp appear OK. The overload condition is also hard on other components in the circuit - especially the plug and receptacle terminals in the shore power cords. I suggest you rebalance loads if possible - if this is successful, you might not need a larger wire size - the larger wire size can't hurt, anyway.

    Joe Wharton
  17. Pascal

    Pascal Senior Member

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    Yeah that’s the theory. Unfortunately pretty much every boat runs close to 100% load in the summer down here. On the 84 I was running we d often trip the 100 amp breaker and pretty much always pulled 90 to 100 amp. Same on the 116 I m running now... with two 3 phase 100, I usually have one of the cords pulling 90 to 100

    At some point I m going add a second 50 amp cord on my 53. It’s just a pita having to deal with two cords everytime we go out
  18. Capt J

    Capt J Senior Member

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    Winter run 1 cord, summer run 2 when you're running 2 chillers maybe.