Finally time to wire my truck. I am re-installing the Haywire brand harness but need to buy some bulk wire too. I assume there are different grades of wire. Is hardware store wire OK or would it be better to go take some clippings from the salvage yard. I need a lot of different colors and would like to keep the cost of this phase reasonable. Just this once.

fenders

 

Man, I don't know fenders. I've been reading about the various wire stranding arrangements, flexibility, plating on the copper, and insulation ratings for smoke, temperature, abrasion resistance, and a bunch of other stuff. It seems like you could get by with premises wiring like THHN or THHW but I don't know if it's all that simple.

There's GPT (General Purpose Thermoplastic) SAE J1128 rated at 176 F, SXL J1128 rated at 257 F, GXL SAE J1128 rated at 275 F, and several others. I've been zeroing in on the SLX grade wire since it has all the properties you'd like in an auto wire like oil resistance, etc. and it has a high temperature rating for under-hood use. I haven't finished searching for suppliers yet but I found

http://order.waytekwire.com/CGI-BIN/LANSAWEB?WEBEVENT+L744CA16A5F900500819A00M+M36+ENG

and the wire doesn't seem too expensive and comes in at least a few colors.

Good luck and let me know what you decide to do. I need all the help I can get!

George

 

George

Thanks for the assist. Your link wasn't cooperating tomight. I don't know a thing about wire ratings. I know the stuff at the hardware store seems like it is more brittle than automotive wire. I'll make sure I use relays where appropriate and not skimp on the wire guage to keep the heat issues less likely to cause problems. Is the heat rating an issue for underhood temps or is it for the higher amperage accessories?

I think I will get a least some of my wire from a salvage yard harness so I don't have to buy 20 spools of wire in different guages and colors. I have worked on cars where everything is red or black. No fun when you are trying to troubleshoot a problem later. The Haywire harness is plenty long enough to reach the switches. I do have to wire into the doors for my PW where they will have to constantly flex everytime doors are opened. Abrasion resistance shouldn't be too big an issue as I will meticulously route and use conduit.

fenders

 

The problem with getting wire from the salvage yard is that its' 50 years old as well, unless you're talking about filching some late model wiring, that would work I guess. Automotive type insulation is designed to be gas, oil, and heat resistant, not all hardware store wire is up to the task, not for long term anyway.




Keep 'er between the ditches.

 

Sacramento Vintage Ford ( 1-888-FORD-100) sells the same wire that they use in their wiring harnesses in bulk by the foot, and it comes in many colors including those with a different color stripe on it so you can keep the color coding on the project original if you like. That would make it easier to trace if you develop a problem later.

 

I have done a lot of this thing. I always collect useable wire on spec. I work in a shop that builds heavy sawmill equip with lots of wiring! I collect what I can, mostly 16 guage. Any equipment manufacturer will likely have excess to unload, you just have to talk to the right person. I know this is not the best wire technically, as there are some very sturdy insulations now, but it is vastly better, when installed properly, than stock. Flea markets can be a marvelous source of wire, too. Be very careful what you buy, you will need lots of 16 ga and far more 10 and 12 ga than you think! Don't use rubber insulated wire-Do run your wires in conduit wherever possible. You can buy plastic tubing from a good hardware store that can accomodate from one wire all the way up to as many as you need. Certainly use conduit in the roof for your dome light. I put in conduit through the post all the way from the dash to the light and then fished the wire through. The dome light is the most dangerous circuit in the truck (next to the dreaded ammeter). Either one will burn your truck down! It is a good idea to wire slightly heavy provided you don't compromise your connections. Always wire from the dashboard out and use lots of twist-ties to group and route your wires as you go. Don't make your final cuts until the wires are properly routed. Use lots of heatshrink-it's cheap. Always remember this-if it looks bad, it is bad!

Good Luck,
Todd.

 

First and foremost you have to look at the ampacity of the wire. If it is too small, you will lose voltage and power in it in the form of heat. Too much heat and you can have fire! 12 gage wire is basically good for 20 amps. 14 gage is good for 15 amps. 16 is good for 10 amps. I wouldn't go any smaller because even if you have low amps, you start getting too flimsy. I plan on using almost all 14 gage for my repairs, with only a few exceptions.

The insulation's voltage rating is not too important. I don't think you can buy insulated wire that can't handle 6 or 12 volts, except varnished wire used for motor or transformer windings.

The stranding of the wire is very important. You can get solid wire but it won't bend easily and will break easily. THHN or XHHW house wire is something like 7 strands and the insulation is very stiff. I would look for more stranding such as what comes in appliances and light fixtures. I would also look for very flexably wire. Machine tool wire, type MTW would be a good choice. Good for oil, moisture, temperature and abrasion. I think it has something like 28 strands.

Running the wire in split plastic tubing is a great idea. All the harnesses in my RV are done in a black rippled tube that is split lenthwise. You just have to use your finger to open the slit and feed in the wire. It is then taped up at the ends. Seems to last and it is easy to pull open to troubleshoot. I plan to use this approach also.

Johann

 

 

>Sacramento Vintage Ford ( 1-888-FORD-100) sells the same
>wire that they use in their wiring harnesses in bulk by the
>foot, and it comes in many colors including those with a
>different color stripe on it so you can keep the color
>coding on the project original if you like. That would make
>it easier to trace if you develop a problem later.

Thanks viking for the SVF source! Only problem is that SVFs price is about 2-1/2 times what the folks at http://www.waytekwire.com are asking for the SLX grade. Course you don't have to buy whole spools from SVF so that's a big plus.

I've contacted SVF and asked them what specification(s) their wire meets. If it's SAE rated at a reasonable temperature it's a good source for the various original colors I need.

Thanks again.

George