350 GTR/GTO Wiring Questions

[moonpup]

Based on the information in the conversion chart I linked above, I'm still getting numbers on the wires in the main harness that correspond to them being 20 gauge.

I also just checked the wires on an old "parts" dynamo out in the garage and CL-100 is correct in that they are bigger. However, again using the conversion chart, they're measuring out to be 18 gauge..... not 16.

I'm trying to build a harness that will be as close to the original as possible, with the exception of beefing up the gauge of the wiring used. I bought some 16 ga. wire based on the recommendations I found here on the site and found that (7) 16 ga. wires won't fit in the protective tubing that goes into the headlight bucket.

I could make it work either using a thinner diameter tube or go with a braided tube, but that would defeat my goal of making a replica harness.

As of now, it looks like the max I can bump the gauge up to is 18 and still retain the original look. There IS one other option that would get me to 16 gauge and that would be using a TXL primary wire that has an extra thin insulation covering. They are actually thinner overall than the regular 18 gauge wire, but I don't particularly want to risk thinner insulated wires rubbing around where exposed.

[BRT-GTR]

    Hi Mike,
                Will be needing a couple of harnesses myself shortly and have been looking at options.

       With a 5amp alternator and 5 or 6 amp/hr battery, the electrical system is marginal as confirmed by CL-100. Totting up the electrical load with everything on gives a max wire loading in the order of 7-8 amps, hence the 10amp fuse. In theory you could wire it all in 20awg or 0.5mm2  !!

    To keep the voltage drops down and beef up the system, I will use 16g for the main wires, IE, All black/red wires to the battery, earth wires  and the blue switched live supply. Everything else can be wired in 17/18g to give a useful upgrade. Some of the minor circuits IE 3w bulbs, neutral switch etc could be 20g. This compares well with previous replies

   I would have no qualms about using the current thinwall wires, they use a harder pvc insulation and should provide good abrasion resistance. The harness is well protected with sleeving, grommets etc. Just make sure none of the unprotected wires are rubbing against metal parts or protect with stick-on foam sheet.

   Did find the more sites I looked at, the more confused I became. Everyone has different ideas or use various wire designations and max current or wattage ratings, so put this table together :-

                AWG                    Area mm2                        Strands/dia                            Amps

                20                             0.5                                 16/0.20                             11
               
                18                             0.75                                24/0.20                            14

                17                             1.0                          14/0.30 or 32/0.20                    16

                16                             1.5                                  21/0.30                            21   

            May not be an exact conversion between imperial/metric but near enough.                     
               
         Hope this helps,     Brian.

               

[CL-100]

I agree with Brian's assessment and like his ideas for where to use the smaller/larger gauge wire on a harness.  I did notice that the wire gauge on the original harness was smaller than I thought, yet the insulation cover was thicker.  It amazes me that the original harness has 20g wire in some places, as Mike noted.  It looks more like the wiring on the dynamo is smaller than I thought.

Well done guys!

Rowland