How big of a wire on a one wire 100 amp alt? To go to a cut off switch then to battery?

I have a 66 Chevelle that has a one wire alt. 100 amps I beleive. THe wire goes to the cut off switch on my fire wall which feeds the line back to the battery. I also had a wire feeding the main harness. It has fried a couple of times. Smoked a wire completely. Most of my other powered wires either come from the fuse block or they come from the switched side of the main switch. The radio is on the hot side to keep the stations in memory and clock.

Do I need a bigger than 10 gauge wire feeding back to the switched side.

Do I still need the horn relay?

Can too large of a wire cause too much pull or push to get the needed amps through? Or is bigger better? Does it matter?

I have several in line fuses to things like my electric fan and other accessories. One in the wire to the amp gauge.

Do I just need to run the return line to charge the battery through the amp gauge?

Or is it better to run it separate.

I put in a new battery after it had been sitting and it fried a bunch of wires.

Thanks
:confused:

I'm running a pair of 8ga wires from my 100 amp alternator to the main junction. It splits off from there according to load requirements.

10 gauge is definitely too small, and a single 8-gauge wouldn't be up to the full capacity of the alternator either.

The biggest factor, though, is the load. How many amps are you drawing? Your wire needs to be able to handle the load, not the alternator.

If you're able to run everything, including bright lights, brake lights, horn, stereo equipment, electric fans, fuel pumps, wipers, etc., without the wire getting warm, you're in good shape. If it gets warm, it's too small.

ttt

Let me take a crack at this. I am a little unclear on a few things, so let me know if I get them wrong.

For the cut off switch, it should have the main battery cable coming in then going out. Next run the wire from the Alt back to the Battery side of the cut off switch. 10 gauge will be too small. I would use atleast 8, 4 gauge for anything more then 8feet. Now run a wire from the Starter side of the safety switch back up to the horn relay, or where ever your power the fuse block from. Once again use the same gauge wire you used for the Alt.

If it's the normal NHRA battery cutoff switch, then you don't need a seperate wire from the switch to the battery, because the battery cable will always be live up to the switch.

Also remeber that the wire from the alt has to be anywhere before the cut off switch and the wire power the fuse block has to go after the switch. If not the car won't shut off when the switch is turned off.

Later
Steve

How big should the wire that goes to the horn relay, and I put on a battery cable 4 guage from the alt to the cut off (switch) side of the main switch. If it is on the other side I still have power going to the fuse block from the 2nd wire on the alt that connects to the fuse block.

It runs and Not wire smoking or hot. The fan is disconnected. I'm going to wire it in with a proper relay and replace the horn relay while I'm at it. It has had very hot wires to it recently.

I used a 6ft 4 guage battery cable like I said from the Alt to the Batt, switch. Should be plenty big especially the extra size will help since the battery is in the trunk.