The Stovebolt Site Forums The Shop Area The Electrical Bay Wire size question

I'm replacing a short length of wire going from the ignition to the + side of the coil, and the short piece of wire from the coil to the distributor. The original wire is 18 AWG; however I have some 14 AWG wire that I'm wondering if I can use.

Is there any issue with running wire that is a little thicker than original? The 14 AWG is flexible enough, and I can't think of a reason why it shouldn't work. Thanks in advance.

Greg,

Using larger wire has no effect on current flow. It's like a freeway...it can't be too big, only too small. If you have ever driven in southern California at rush hour you will know exactly what I'm talking about.

Stuart

Thanks Stuart--good analogy. I found the right guage and right color wire at the FLAPS, but the price was through the roof, and much more length than I needed. I was considering McMaster-Carr but they didn't offer enough color selection.

So, does anyone out there have a good source for automotive wires (preferably by the foot) of varying sizes and colors? A few places I've seen require you to buy a LOT of it.

I'm just not at the point where I feel I need a whole new wiring harnass, and it would be nice to keep the original guage and color.

Greg,

Harbor Freight has a little wire caddy that has various sizes and colors on small spools. A neat deal EXCEPT, I have been told by a few folks that the insulation isn't very durable. If the wire is made to standard AWG gauge, and the strands are copper, then the biggest other concern would be the toughness and cut resistance of the insulation. The Chinese wire might all flat on its face in this regard.

Ace Hardware has THHN and THWN insulated wire on spools in my area. This is the Cadillac of insulation's and a excellent wire. The drawback for automotive purposes is that it tends to be a little less flexible than standard automotive wire.

I like the stuff and have a unlimited supply in a bazillion colors and gauges...so guess what my old truck is getting wired with. Good luck on your search.

Stuart

All you need to use is a heavy guage wire. try lowes or home depot. they charge by the foot.

I'm an electrician and a good rule of thumb is bigger is better. On your vehicle a good 14 gauge is all you'll really need for just about anything. Most THHW or THHN wire is gas and oil resistant, perfect for automotive use. The insulation is usually thicker than automotive grade wire. The only downside is that it is a litter stiffer and likes to curly cue. Some tape or tie wraps should take care of that though.

Wire sizing chart:
14 gauge: 15 amps
12: 20 amps
10: 30 amps
8: 45 amps
6: 55 amps

I redid the wiring in my truck, just finished yesterday, and I'll agree with everything that has been said here. I ended up buying several 50-ft spools of 18 gauge wire in various colors to replace what was originally 20 gauge and some 16 gauge and 14 gauge wire to replace the wires shown as 18 gauge in the shop manual. I don't have all of the colors exactly correct, but I don't think the truck minds.