Wire Gauge Ampacities

**anonim** · 07-11-2007, 10:44 AM

I'm looking to run a wire from the battery to the trunk to power a device which draws 5A at 15V = 75w.

It seems like every AWG ampacity table I find online has differing numbers as far as how much current can be carried per gauge. I'm looking for the minimum gauge wire that will safely handle 10A up to a distance of 15 feet.

As an example:

10A => 18AWG
http://xtronics.com/reference/wire_gauge-ampacity.htm

10A => 12AWG
http://www.powerstream.com/Wire_Size.htm

100RMS at 16-feet => 8AWG
http://www.the12volt.com/info/recwirsz.asp

There's quite a large difference between a 8AWG and 18AWG wire. I want to make sure I don't fry anything (or myself).

**gsd_racing** · 07-11-2007, 11:03 AM

While I cannot directly answer your question, I can give you some input. The current handling capacity of the wire is VERY dependent on how its constructed. The stranding, both the number of strands and how its twisted can both improve and hinder current handling. I'm sure someone will chime in on this, so I hope it was a start for you

**DarquePervert** · 07-11-2007, 11:18 AM

Assuming you're talking about 12v, 10awg should be fine for for that short a run.

**anonim** · 07-11-2007, 04:07 PM

Okay thanks. I thought 8awg was a bit overkill too.

**JimmyFitz** · 07-11-2007, 04:56 PM

Some guys on here will disagree with me, but you would be safe with 18AWG as well. If you are only going to draw 5A and only one device, you don't need fatter wires. If you think you might add amps or anything else back there later, go ahead with bigger wire now.

Whatever size wire you use, fuse it up by the battery so that if you ever get a short to ground, you will blow the fuse instead of setting the car on fire.

**turbocad6** · 07-11-2007, 05:25 PM

yeah, 5 amps is a light load, I'd use a 16ga or so, 18 would be ok too, anything bigger than 16ga is overkill... check out the factory wire size that runs your brake lights... similar load, usually a bit longer than just a straight run considering all the harness routing & still maybe 16 gauge... a 10 gauge would run like a 40amp load really

**Defiler** · 07-12-2007, 11:51 AM

Here is a good doc on power ratings and what you would need. Bottom of first page.

http://www.knukonceptz.com/assets/pdf/PowerWireSpec.pdf

And BTW...Knukonceptz.com rocks.