Batboard

I used to have a chart that said for any given run length and a current draw, it gave the correct wire gauge. Only I can't find it, so if anyone has a chart or equation I can borrow, I wanted to run [email protected] 18 feet.
Thanks.

For this legnth, I'd use NO LESS THEN 4ga wire. IF you can, use 2ga or 1/0ga. The larger the wire, the less resistence you will have.

This is really to settle a disagreement with a friend, he thinks only #4 is required and I think that sounds pretty marginal and that he should use #2.

You need more information to give a correct answer,
you could, under different conditions both be correct.
You need to know the type of wire, # of strands, type of
insulation, and ambient temperature.
All the information can be gleaned from the manufacturers websites.
Or article 310 and tables 310-16 through 310-19 of the
National Electrical Code.
J.B. AD6WX

Using automotive ASE grade wire if you are using an appliance that is drawing 110 amps at 13 volts you should use 4 gauge wire....anything less is overkill and anything greater is too little. Just out of curiosity how did you arrive at 110 amps, what equipment are you running....Is it a mobile radio???

What in the hell are you doing that needs 110 AMPS at 13.8v ????

Did you put 2 FS Visions and a signalmaster on your SUV?

Just curious, but did you mean a 110 WATT mobile radio?[/b]

I build vehicles all of the time that draw 110+ amps current. A police car with MX7000, grille flashers, deck flashers, 90W corner strobes, dash light, wig wags, backflasher, arrowstick, video, MDT, cellphone, 2 Maglights, 2 radios, scanner will pull 110 amps easily on their single power feed.

Don't pay attention ot the National Electric Code- you are working on a vehicle and not a building. This is VERY different.

Follow SAE guidelines for automotive use and also, make sure all of your materials are SAE approved.

#4 "battery cable" will work at 110 amps with only a slight voltage drop or heat shed.

WELDING CABLE IS NOT SAE APPROVED, so if your installation fails or the car burns up, YOU are the one that used a non-approved cable in the installation! Although welding cable is a high quality "high strand" cable, it is not intended to be used in a vehicle.

check out the westmarine.com website, they used to post charts for 12-14 volt marine use, but I don't recall them going that high -- maybe in their inverters section.
110 sure doesn't leave much alternator left over! suggest a high idler.

Go here:

http://www.wattco.net/

Open Web Page

Click on "Installer/OEM Information" on left side

Scroll down to "Wire Gauge Size Reference Chart"

It goes up to 100 Amps.

Yikes, that last table says I can run 12AWG for
three feet @ 100A. Makes my butt pucker just
thinking about it.
BTW, I understand that the NEC is for buildings,
just thought that it was a good source to compare,
my bad.
J.B. AD6WX

who is a good inexpensive vendor of SAE wire?

Del City @ 1-800-654-4757
TSD @ 1-800-428-4449
American Terminal Supply @ 1-800-826-4697

As always, there are several types of wire. Some rated for one use, some rated for others. There are also some that aren't SAE rated at all and some that are SAE rated for certain locations such as high heat.

For general SAE wiring, the "crosslink" is a good quality and inexpensive wire.