wiring question

Reply Subscribe

Thread Tools

Search this Thread

Jan 4, 2009 | 09:40 PM

fredbuilt

Thread Starter

Junior User

Joined: Jan 2007

Posts: 69

Likes: 0

From: Boothbay Harbor Maine

wiring question

I want to run a positive and a ground coming from the battery to run some accessories. Will 18 gauge wire be enough to run 20 amp accessories?

Jan 4, 2009 | 10:14 PM

Franklin2

Moderator

Joined: Jan 2001

Posts: 56,992

Likes: 2,741

From: Virginia

I don't think so. The factory pushes the wiring sizes to the limit, and they accept the voltage drop that goes along with it. After all, copper is expensive, and if you can save a buck on several thousand cars and trucks, well....

I go by the old house wiring standards. It seems to be a little bit bigger than the factory used, but you can be assured there will be minimal voltage drop.

16 gauge-10 amps

14 gauge-15 amps

12 gauge-20 amps

10 gauge-30 amps

Jan 4, 2009 | 11:29 PM

ReAX

Post Fiend

Joined: May 2006

Posts: 10,007

Likes: 4

From: Central Florida

I am going to disagree a tiny bit. Pick you wire by length and gauge, there are a lot of calculators available. I use something similar to this, http://www.rbeelectronics.com/wtable.htm

Jan 5, 2009 | 12:55 PM

Franklin2

Moderator

Joined: Jan 2001

Posts: 56,992

Likes: 2,741

From: Virginia

Quote:

Originally Posted by ReAX

I am going to disagree a tiny bit. Pick you wire by length and gauge, there are a lot of calculators available. I use something similar to this, Wire Gauge Tables

That's an example of running the wiring closer to it's rating, which is fine. What I listed is just what's in my head from doing electrical work and although it's a little overkill, it will always work and probably go any distances you will see in a vehicle.

Jan 6, 2009 | 11:56 AM

jimdandy

Posting Guru

Joined: Feb 2006

Posts: 1,448

Likes: 1

Here is another handy site. No more than 16amps for 18ga.

American Wire Gauge table and AWG Electrical Current Load Limits

Jan 15, 2009 | 07:21 PM

Fandini

More Turbo

Joined: Aug 2006

Posts: 598

Likes: 5

From: Burlington, NC

Quote:

Originally Posted by ReAX

I am going to disagree a tiny bit. Pick you wire by length and gauge, there are a lot of calculators available. I use something similar to this, Wire Gauge Tables

That can't be right.........can it? This is saying that if I have two 120 watt driving lights that it is pulling 40 amps at 12 volts. That can't be right. To figure amps in household current you divide the watts by the voltage or you can multiply the amps by the voltage to get the watts. There has got to be a more accurate way of calculating what your chart shows. Am I way off base here?