Rewiring

[ron]

Hi Guys,
Information please this coming weekend I intend running new wiring through the conduits, can any one tell me what size wire that I will need for the job, I want to wire it for 12 volts, I am prepared to change the coil starter moter and generater and any othe bits that I might have to, but its the wire size that I need,
Regards,
Ron,

[jim sewell]

Ron
Have posted a wire chart .
To work out the amp draw of say the lights etc use the formula that Watts = volts x amps
Example 100 watt light would draw approx 8.5 amps in a 12volt system .
Ignition draws 4 amps
Generator may charge 40 amps
By working out the amp draw you will be able to select the correct size wire .
All the best
Jim S.

[Grant Bowker]

Assuming that the conversion to 12 volts is from 6 volts, you could use the same wire guage as was originally used. This has the benefit of less voltage loss in the wiring so that lights will be somewhat brighter and the starter should seem more powerful. Use of "oversize" wire and relays is common in rally cars for maximum light output. The gains of doing this will be most visible on systems that were originally wired with conductors at near their maximum capacity. I don't know of any problems with using "oversize" wire except that it weighs more which isn't much of an issue on a carrier/CMP and costs more per foot which again shouldn't be a large issue given the relative simplicity of carrier/CMP electrical systems.

One caution that should not apply to Ron's question, do NOT try this on 24 volt to 12 volt conversions, potentially disastrous overheating of wires may occur.

[Phil Waterman]

Hi Ron

Grant brings up a very good point in rewiring using the same size wire as was used with 6 volt the voltage drop will be far less than if you sized the wire for 12 volt. Another thought when rewiring is the terminals used and how they are attached to the wire. If you compare the spade lugs used on most WWII military vehicles you will find that the lugs are wider and thicker than what you find at the normal hardware store. (I’ll try to take some pictures to illustrate this point today) So it is worth looking around to find the heavier duty lugs and connectors try a commercial electrical supply house. Where practical I would use the ring type connector instead of the spade type, ring gives more contact area and contact area is key to flow of power through system no point in putting a heavy wire if the terminals at the ends have less contact area.

Also you will note that almost universally WWII stuff has the terminals dip soldered on to the wire instead of just crimped. When making up new wiring harness (or repairing old) I try to follow the following steps:

1. Slip the little rubber tube length of the wire (Chevy CMPs used a short ¾ long piece of rubber tubing that just slides over the wire and back over the barrel of the terminal as a strain relief )
2. Strip the end of the wire just enough to go through the barrel of the terminal use the correct size stripping tool so as to not cut or score and of the wire strands.
3. Tin with solder the end of the wire, this can be done with a soldering iron and solder, use just enough solder to hold all the strands together but not so much as to change the size of the wire.
4. Slip the appropriate type and size terminal onto the wire end (if you are using modern terminals with the plastic covers, remove the plastic first) then lightly crimp the barrel of the terminal of the wire just enough to hold it on
5. Apply heat and solder to the barrel of the terminal until solder will flow and run in just enough solder to be sure the barrel is well soldered to the wire. (let cool)
6. Slide the rubber tube down the wire until it has slid over and covered the barrel of the terminal.

The result is terminated wires that look good, are less likely to corrode, brake off at the terminal, and most important will pass the rated current of the wire size without heating up.

[Alex Blair (RIP)]

Originally posted by ron
Hi Guys,
Information please this coming weekend I intend running new wiring through the conduits, can any one tell me what size wire that I will need for the job, I want to wire it for 12 volts, I am prepared to change the coil starter moter and generater and any othe bits that I might have to, but its the wire size that I need,
Regards,
Ron,

Ron..
You will find that most problems that I have encountered with repairing,driving and maintaining automotive were related to poor grounding...I always used welders cable to make my own ground strap..It is more flexible because it is designed to flex and is braided rather than stranded...
Ground your block from each head and from the block in at least two places...to the frame and to the body ...
Also ground your body and frame again in the front..Using braided ,rather than stranded(Never solid) and soldering ALL terminals and lugs will keep you operating electrically ..
Make sure that you grind your grounds clean and use a protective dielectric grease after you make all your connections..This will help retard corrosion over the long run..Pay paticular attention to your starter grounds and make sure you have new bushings and brushes in your starter..
Your grounding is the most important part of your wiring and usually gives you the most trouble down the road unless properly installed and maintained..

[Phil Waterman]

Good point on necessity of grounding, I’ve gone chasing my tail on fresh restorations where I had not used the star washers or ground straps cleaned right down to the bare metal all that great fresh paint. Found that some times you can read voltage through a connection but the connection won’t pass current at load.

Attached picture hope illustrates the size of the spade connectors and the use of the rubber tube stain relief, first frame shows the lug type connectors meant for heavier current flow. The last frame is what I keep and eye out for old selections of wiring connectors this is one I picked up at a flee market.

[ron]

Hi Jim,
Thanks for the information, I am going to have a go at it in the morning,
Regards,
Ron,

[ron]

Hi Grant,
I had not thought of using the old size wire thats a good idea, I will pull it all and see how good it is,
Many thanks,
Ron,

[ron]

Hi Phil.
Thanks for all that information that will be a great help I am not good at this part of the restoration, but I can do it now I am sure, you have all been a big help thanks guys,
Regards,
Ron,

[ron]

Hi Alex,
Good thinking on the earthing or grounding , I have lots of paint on the steel, So you have made an excellent point, I may not have taken enough care in this department with out your suggestion, I will make sure that I have a good earth,
Thanks
Ron,

[Lynn Eades]

As Jim has already alluded to. If you use the same cross section of wire as was there originally, 12 volt will work fine. If how ever you reduced the cross section to what would currently be recommended for 12 volt, you would not be able to go back to 6 volt without a rewire.

[ron]

Hi Lyn,
Good thinking Lyn I had not thought of that one,I might stick to the six volt wire then,
Thanks, Regards,
Ron,

[Bob Moseley (RIP)]

Hello Ron
For your interest, from the Spare Parts Manual, wire colours. Be a purist, stay with 6v.
Bob

[Bob Moseley (RIP)]

Here it is in all its glory.
Bob

[Tony Smith]

Originally posted by Bob Moseley
Here it is in all its glory.
Bob

Forget the thickness, can you tell us the length, Bob? (Of each wire circuit, that is!)

[ron]

Hello Bob,
Thank you for the information I knew that I could rely on you, I saw the colour code in the spare parts manual that you kindly sent me some time ago, I will take your advise I will stick to the six volt system, I got a heap of parts today,all the odd smal bits that I needed, its been a good year really and I owe a lot of it to you,
Many thanks Bob,
Regards,
Ron,

[Bob Moseley (RIP)]

Hello Tony
Unfortunately the manual doesn't get real specific about the wiring looms, however given that the overall Carrier length is 12' 6" a tape measure combined with the wiring schematics should give you a rough guide. However, in retrospect, I am sure Ron will give us all the wiring loom details as he expertly constructs one. This will henceforth be known as the "Ron Carrier Loom"
Bob

[ron]

I forgot to put this pic in here of the coduit layout with the new wires threaded through not the easiest of jobs to do but its done now, and should last for a long time
Ron