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  1. #1
    Petty Officer 3rd Class
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    Default Windlass Cable Size, 2-AWG or 4-AWG

    Hello, I am installing a Lewmar 700H Pro Series Windlass on a 21' CC. My batteries are in the console, so the wire length will be approx 18' to 20'. I am planning to use ANCHOR tinned wire in the 4-AWG size. The installation guide recommends to use 8-AWG size, but West Marine recomends to use 2-AWG size.

    Do I really need to go to a 2-AWG?...as a 4-AWG is already doubling the manufacturers recomendations...thanks.

  2. #2
    Moderator JB's Avatar
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    Default Re: Windlass Cable Size, 2-AWG or 4-AWG

    With that long run I would use #2, gg.

    #4 would probably be okay if the batteries were close, but 18-21' is a long run.

  3. #3
    Petty Officer 1st Class PondTunes's Avatar
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    Default Re: Windlass Cable Size, 2-AWG or 4-AWG

    Quote Originally Posted by JB View Post
    With that long run I would use #2, gg.

    #4 would probably be okay if the batteries were close, but 18-21' is a long run.
    Agreed you're running a very long way and operating a high draw accessory you should use #2. Not saying #4 wouldn't work but it's in the gray zone imo.

  4. #4
    Lieutenant Commander wire2's Avatar
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    Default Re: Windlass Cable Size, 2-AWG or 4-AWG

    What's the current stamped on the name plate?

  5. #5
    Lieutenant Commander wire2's Avatar
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    Default Re: Windlass Cable Size, 2-AWG or 4-AWG

    Length of conductors is 40 ft (2 x 20 ft
    Resistance per foot of #4 copper is .000292Ω
    Resistance of 40 ft is .01168Ω
    Current is 35 amps.

    Voltage drop (E = IR)of #4 is .40 volts or 2.9%

    Voltage drop of #2 is .3 volts or 2.1%

    Voltage drop of #6 is .7 volts or 5%
    In other words, with battery at 13.8v, windlass will receive 13.1v. No problemo.

    Personally, I'd go with #6 as it's a very intermittent load.
    Mercruiser trim pumps are also 35 amps, I believe they get only a #10 wire. At 5 ft + 5 ft it's a 5.7% drop.

    West Marine is covering their butt. Extremely.
    Last edited by JB; October 3rd, 2007 at 05:55 PM. Reason: deleted forbidden commercial link. See rule #10

  6. #6
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    Default Re: Windlass Cable Size, 2-AWG or 4-AWG

    Thanks alot guys, lots of great information. Wire2, Lewmar also recomends going with AWG 6 for my application....impressive calculations BTW.

  7. #7
    Lieutenant Commander wire2's Avatar
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    Default Re: Windlass Cable Size, 2-AWG or 4-AWG

    Quote Originally Posted by gearyg View Post
    Thanks alot guys, lots of great information. Wire2, Lewmar also recomends going with AWG 6 for my application....impressive calculations BTW.
    It comes easy for a licensed electrician.

    You're welcome.

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