You haven't said what the wire is feeding, or where it is (both of which may affect the right choice). The easiest chart I've seen so far is this one on the Blue Sea Systems website. It talks you through the various considerations, and allows an accurate result to be achieved. The only problem is that it gives the result as an AWG (American Wire Gauge) figure - look here on the Index Marine site for a conversion table to approx sq mm size.
Well, you can of course (and indeed should) use whatever wire you feel happiest with, but there's not much point using a wire calculator if you then ignore the results! /forums/images/graemlins/wink.gif
By the way, your claim that "Voltage doesn't matter....." isn't correct - if you don't know the voltage you can't calculate the percentage voltage drop, which is the factor most commonly used in deciding wire size.
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Well, you can of course (and indeed should) use whatever wire you feel happiest with, but there's not much point using a wire calculator if you then ignore the results! /forums/images/graemlins/wink.gif
By the way, your claim that "Voltage doesn't matter....." isn't correct - if you don't know the voltage you can't calculate the percentage voltage drop, which is the factor most commonly used in deciding wire size.
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Personally, I would use the calculator but then if it gave a very small min. wire diameter I'd probably increase that figure to boost its mechanical strength unless it was going to be in a very protected environment.
thank you all for your help iam fitting out a new charter boat from just the mouldings 3 half weeks in and all is going well bulk heads in console and tanks rendy to lay deck when weve done some of the fit out