#8 wire in Van's wiring kit?

13brv3 · #1 06-30-2006, 03:39 PM

Greetings,

I'm closing in on my wiring adventure, and am trying to get everything pre-planned. I've got the wiring kit that Van's sells, and see that it shows 35 or 60 amp alts, but both show a #8 wire.

According to the article on Electric Bob's site, #8 isn't large enough for 60 amps. Are people commonly using this without any difficulty, or are you upgrading those wires to #4 or so when using a 60 amp alternator?

http://www.aeroelectric.com/articles/wiresize.pdf

Thanks,
Rusty

Captain_John · #2 06-30-2006, 04:17 PM

If I were to do it today, I think I would go #6.

CJ

mlw450802 · #3 06-30-2006, 04:53 PM

http://xtronics.com/reference/wire_gauge-ampacity.htm

-mike

13brv3 · #4 07-01-2006, 07:26 AM

Thanks for the comments. It looks like #8 is the bare minimum that you can make work, but not necessarily the safest choice. I think I'll use #6.

Cheers,
Rusty

rv8ch · #5 07-01-2006, 01:35 PM

Van's has a nice chart that I use regularly. It's in the early part of the preview plans - can't recall which page. I have a post-it tab on there, I use it so much.

It has current on the Y axis, wire length on the X axis, and you can read the AWG wire size inside the chart.

I have not compared it to the calculations in Bob's book, but knowing Van's, it is probably conservative.

Using smaller wire size can generate extra heat, and as a result, extra losses.

I used AWG#6 welding cable from McMaster-Carr to hook up my 55 amp alternator to the batteries in the tail. Works great in the shop, and I'll bet AWG#8 would work fine, too.

13brv3 · #6 07-01-2006, 02:10 PM

Hi Mickey,

I just took a look through the front section material in my preview plans book, and don't see a chart that goes up to 60A. The highest it lists is 40A, and that can be used with up to about 15 ft of #8 wire. It still looks like 60A with 6' of #8 wire would be pretty miminal, though it must work if Van's keeps putting it in the drawing.

You'd really have to know the criteria used to generate the chart in order to make it more useful. Bob sets max current to create 10C and 30C temp rise in the wire, then sets max length to lose 5% of the starting voltage. Most charts don't give you any info like this.

The good news is that I won't ever be pulling that much current for any length of time. I don't imagine my entire system could pull more than 30-40 amps, so once the battery is charged back up from cranking, I'll be well below 60A. I'll probably still change it to #6 just for peace of mind.

Cheers,
Rusty