What guage wire for battery switch?

[Saffie]

Going to put a battery selector switch in my boat. Looked on the manufacturers site and can't find what guage wire I should buy to make the connections between the batteries and the switch. Looking at some sites to order the wire and the selections are confusing.

Thanks

[LittlePech]

Heavier the better, I'd go at least one gauge higher then the largest existing wire on your output.
So if your largest existing output wire is 8 I'd go 6.
If your batteries are not side by side, depending on the distance between, and if its for starting I'd go with an even lagger wire.

[Marshfly]

I would never run less than 4 gauge from the battery to the switch no matter the distance. However 4 will be enough in the distances in a bass boat. Make sure your negative cable is an equal size. It is just as important as the positive cable. Think of the cables as hose and the battery a pump with the system being a big loop. If you restrict the negative by using too small of cable, it's exactly the same as using too small of a positive lead.

BTW 8 gauge is only rated by ABYC to 80 amps and 4 is rated to 160. That is on the shortest runs for the shortest time period. Your starter will draw considerably more than 80 amps.

[Saffie]

Thanks gentlemen. That helps me alot. From what I read it seems the 6 guage is the way to go for my application. Thanks again.

[Marshfly]

Thanks gentlemen. That helps me alot. From what I read it seems the 6 guage is the way to go for my application. Thanks again.

If you are running your outboard through that switch, 6 gauge is not enough. It won't take much of a discharged battery before you don't have enough juice to start the motor. Frankly, I have never even seen an outboard installed with less than 4 gauge. if you are just running electronics, lights and pumps then 10-8 gauge would be enough.

[Saffie]

Will go with the 4 guage. Was thinking 4 and for some reason typed 6. Thanks for the advice.

[Marshfly]

Will go with the 4 guage. Was thinking 4 and for some reason typed 6. Thanks for the advice.

Do it right. Do it once.

[Jonestrollingmotor]

If the outboard is part of the selector, check the battery cable size on the outboard and match that size.

[LOSTTEXAN]

#4 minimum, #2 will cost another dollar or two.