What type of wire?

My SC is in desperate need of some new wire. There are several frayed wires, the battery dies overnight if left hooked up, the lights don't work and my alternator is only putting out 12V. I am off tomorrow and plan on rewiring everything.
I have been thru the archives and have a note book full of advice. I have bob M's diagrams. I have a chart on the different types of 10SI alternators. I have a pile of parts (connectors, switches etc.) and I have all my tools ready.

Butt I have one more question before I begin...
What kind of wire should I be using. The wire in the auto store is not marked, comes in small rolls and is rather expensive. Especially when compared to the local hardware store which has THHN and SO by the foot. Are these wires the same or interchangeable? What wire type would be best?

I dont have my book handy, so im not sure what SO and THHN are off the top of my head. I like to think im electronically inclined, tho I have only rewired one antique tractor, I've built a couple model railroads, installed fog lights, etc on cars, and done a few competition subwoofer installs.

For anything like what your about to do, I personally go for the rolls of wire from the auto store or similar. Roughly 20 to 25 feet in length, in a variety of gauges and colours. If your only going to do this once, your only going to need a couple spools, more if you want to colour code, or get complex with lights, etc. If you have a dozen tractors to rewire, look into buying that same wire on spools. I know my local NAPA, and a buddies shop locally, can supply me with wire on spools ranging from ten feet to five hundred feet. Where I tend to do this sorta thing semi-frequently, I've learned that buying wire in 100-foot rolls is cheaper, but it doesn't make much sense for you, if your only going to use 15-feet and have the rest sat in the shop.

To make a long answer a bit longer...I dont think that wire type matters, so long as its a suitable gauge (If you have Bob's great diagrams, the gauges needed are listed) and is stranded copper (solid copper is suitable, too, just avoid anything else).

Cheers, and I hope this was of some assistance!
AR

Use the THHN. Its insulation is rated for high temperature. SO cord is like extension cord with multiple conductors in one sheath. The letters SO describe what the sheath is resistant to but I can"t recall right now.

SO is sunlight & oil resistant jacket. If you have a 10SI, you really only need 1 length of #9 wire to go from the alt. "hot" terminal back to the ammeter.
Sounds like you have a bad voltage regulator [internal] &/or a shorted diode in the rectifier. Prove this out by disconnecting the wires at the alt. overnight. You would be better off with stranded wire for hook-ups.

The THHN will work fine, you can use #12 for everything except use #10 or #8 for the alternator. Be sure to properly crimp your connectors, pinching them with pliers or a makeshift crimper will cause problems. Use a Klien or Ideal brand crimper if you can.

The SO cord you referance is called Portable Cord. The letters have the following meanings...

S = 600 Volt Service Cord

J = Junior Service - 300 Volt

T = Thermoplastic

E = Elastomer - thermoplastic that looks and feels like rubber

O = Oil Resistant Outer Jacket

OO = Oil Resistant Outer Jacket and Oil Resistant Insulation

W = Weather and Water Resistant (approved for indoor and outdoor use)

Portable cord is good for lots of things but tractor wiring isn't one of them, in my opinion. I had two runs of SO on my baler wiring between the cab and the baler and the sunlight just destroys the outer covering. Switched to MTW (THHN approved for Machine Tool Wire) in expandable sleeving and have no problems since.

The automotive wire is more flexible and easier to work with. I've used THNN and it's like trying to work with a slinky.

Whatever you do, secure the wire so that it can't vibrate around and rub through. Encase the wiring in some sort of loom. You can get corrugated plastic split looming from auto parts stores, Harbor Freight, maybe even Home Depot and Lowes.

If you want to just buy one roll of wire for convenience, Id use 12 Gauge fine strand copper THHN or THWN automotive "hook up" wire as opposed to SO cord which is more for drop and extension cord use having two or three conductors in a single jacket. You could get by with 14 gauge for some or all of the wiring but it wouldnt hurt to use 12 just to save buying two rolls of wire.

ON 6 volt applications I like at least 0 better yet 00 Gauge Battery and Starter and Ground Cables or 0 or 1 Gauge on 12 volt.

Or try Jim up in New York at Agri Services www.wiringharnesses.com for a whole new wiring harness

John T

You need #10 fro the one wire off the big post of the alternator and all others can be #12 or #14 I prefer #12 because it is heavier then the #14 so holds up better over time.

I went to the local electrical supply place and got solderable connectors and got dual-wall heat shrink from harbor freight when I wired my trailer. Everything is sealed.

I got the stiffer stranded wire from Home Depot and used it where the wires don't bend a lot and it's been working good for 3 years now.

if you are not going to use the wire from the automotive shop then get MTW wire from the electrical supply house. I would not use THHN. It is too stiff.

THHN is definitely too stiff. Makes it hard to avoid contact with the metal inside the dash because it does what it wants. I redid my 140 with NAPA 12 (plus 10 for the alt.) gauge about 25 years ago with a NAPA split plastic loom from dash to the alt., distributor and lights. Updated easily when I went to alt. from gen and added more and bigger lights. I did brown for ground, red for 12+ to coil and alt-to-batt, purple for lights, and yellow for alt light. Five colors should do it for most basic setups.

I also used basic round appliance cord for the combo rear light (black/white/green becomes tail/white/ground). Been on there 25 years--holds up great.

Do not use solid THHN wire from the home store. Not only is it hard to work with because its stiff, but vibration will cause the copper to work harden & break.

SO would probably work, but I can't imagine it being cheaper than automotive wire. For a given wire gauge, finer strands = more flexibility and less likely to break.

Soldering connectors is a good idea, just don't get carried away with the amount of solder. Heat shrink tubing does a good job of sealing connections.

For what's probably a trivial difference in price for the small amount of wire you need, use the right wire and the appropriate terminals. You'll have a lot less trouble later.

Keith