FAQ:12v Wire sizes and Fuses Made Easy

[GerryS]

Not intending to be troll....I'll keep my mouth shut...

[Bogo]

http://www.gmupfitter.com/publicat/elec ... df#page=22

It explains why all my GM vehicles end up needing their ground wires replaced with heavier ones.

Yes, I'm saying I think they are skimping on wire size.

[Bogo]

If the wires are large enough and not fused you can weld with DC.
If the wires are small enough and not fused they act like resistance heating element wires.

Depending on what yer trying to accomplish the above can come in handy.

You can even do some playing around like I did for one project and push 200 Amps through a 22 AWG wire. Just don't try to do it for extended periods like for more than a tenth of a second. It takes some time for the heat to build up enough that it acts like a fuse. Actually, that's all fuses are. A small piece of wire meant to burn up if to many amps try to pass through it. Usually they contain the wire in something, like a glass sleeve, that will keep the molten metal from damaging other things.

[eamarquardt]

If the wires are large enough and not fused you can weld with DC.
If the wires are small enough and not fused they act like resistance heating element wires.

Depending on what yer trying to accomplish the above can come in handy.

You can even do some playing around like I did for one project and push 200 Amps through a 22 AWG wire. Just don't try to do it for extended periods like for more than a tenth of a second. It takes some time for the heat to build up enough that it acts like a fuse. Actually, that's all fuses are. A small piece of wire meant to burn up if to many amps try to pass through it. Usually they contain the wire in something, like a glass sleeve, that will keep the molten metal from damaging other things.

I have about a 12 gauge cable that is designed to carry about 250 amps. I've pushed it to about 300 amps on a couple of occasions. It only works well when I've turned on the water cooling system though. Ask me how I know it doesn't work well with the cooling system not turned on. I have, though, fabricated a couple of SST (Special Service Tools) and can repair a damaged cable for about $15 versus buying a new one for $60.



Cheers,

Gus

[teddy]

I was a bit bored at work today, so i made this chart. Based on metric, so the feet are not well rounded numbers, and AWG may not be the most used ones. But it may provide a handy comparison between the 2 systems.



PDF version here