I intend to make a new wiring harness for my 59 Gold Flash. Can anyone advise what range of wire sizes (AWG) I should be looking at? From what I can make out 18 AWG should be sufficient for the bulk of the loom.
Any help will be much appreciated.
Try Vehickle Wiring Products, Tel 01159305454 you can get everything you need there.
Thanks John
On my B33 I used a mix of 14/0.3 and 28/0.3, with the thicker cable for headlamp, battery and dynamo/regulator connections (the dynamo F terminal can use the smaller size). I would also run a separate earth connection to the rear light assembly.
Philip.
I would recommend using separate earth connections rather than relying on the frame. Bring them all together out of sight but still accessible. Add a couple of fuses, one for the brake light and horn and another for the rest. The brake light and horn aren't usually fused but I had a problem once where an internal short developed in the horn during a ride and I only noticed it when the ammeter showed a high charge rate. I pulled over and found the hot wiring which was quickly disconnected before it burnt out.
If you are converting to 12v (and why wouldn't you!) you can reduce wire gauge thus making the harness much easier to feed around the bike and less conspicuous.
I would always over engineering the wiring. When I re-designed the new loom including new equipment, I added all the loads in Amps on each wire, added for the circuit and doubled them and got the appropriate wire. I find it useful to design in Fuses so if you get a problem 1. Not everything goes down and 2. you know better where to look.
I don't like AWG American Wire Guage, Europe uses the diameter and number and size of copper strands.
I use a chart as below
AWG Diameter Area Resistance Max Current Max Frequency
[inch] [mm] [kcmil] [mm2] [mΩ/m] [mΩ/ft] [Ampere] for 100% skin depth
4 0.2043 5.189 41.7 21.2 0.8152 0.2485 60 650 Hz
5 0.1819 4.621 33.1 16.8 1.028 0.3133 47 810 Hz
6 0.1620 4.115 26.3 13.3 1.296 0.3951 37 1100 Hz
7 0.1443 3.665 20.8 10.5 1.634 0.4982 30 1300 Hz
8 0.1285 3.264 16.5 8.37 2.061 0.6282 24 1650 Hz
9 0.1144 2.906 13.1 6.63 2.599 0.7921 19 2050 Hz
10 0.1019 2.588 10.4 5.26 3.277 0.9989 15 2600 Hz
11 0.0907 2.305 8.23 4.17 4.132 1.260 12 3200 Hz
12 0.0808 2.053 6.53 3.31 5.211 1.588 9.3 4150 Hz
13 0.0720 1.828 5.18 2.62 6.571 2.003 7.4 5300 Hz
14 0.0641 1.628 4.11 2.08 8.286 2.525 5.9 6700 Hz
15 0.0571 1.450 3.26 1.65 10.45 3.184 4.7 8250 Hz
16 0.0508 1.291 2.58 1.31 13.17 4.016 3.7 11 K Hz
17 0.0453 1.150 2.05 1.04 16.61 5.064 2.9 13 K Hz
18 0.0403 1.024 1.62 0.823 20.95 6.385 2.3 17 K Hz
19 0.0359 0.912 1.29 0.653 26.42 8.051 1.8 21 K Hz
20 0.0320 0.812 1.02 0.518 33.31 10.15 1.5 27 K Hz
21 0.0285 0.723 0.810 0.410 42.00 12.80 1.2 33 K Hz
22 0.0253 0.644 0.642 0.326 52.96 16.14 0.92 42 K Hz
23 0.0226 0.573 0.509 0.258 66.79 20.36 0.729 53 K Hz
You may find the following web page from 12 Planet useful with a video and conversion chart https://www.12voltplanet.co.uk/cable-sizing-selection.html
thanks, Lionel