Grants Tillers Excellent website can be found here.

I am not the author of the article below.

For a number of years I have made my own looms. I am hopeful somebody finds this useful. 

it’s changed a bit, as Lucas used to have their own gauge wire made for them.

The typical wire sizes used by Lucas that we see on our classic bikes, are rated as follows:

  • 44 strand
    44/0.12 (44/0.30mm) 22 amp
  • 28 strand
    28/0.12 (28/0.30mm) 14 amp
  • 14 strand
    14/0.10 (14/0.25mm) 6 amp
    14/0.12 (14/0.30mm) 7 amp
  • 9 strand
    9/0.12 (9/0.30mm) 4 amp

Note 1 – the 14/0.10 was superseded by the 60s
Note 2 – modern cables of the same spec are rated higher than the figures Lucas give (as shown here)

The two companies that I use for my wiring are:

The wire types I use on bikes are mainly:

Thin Wall Cable

  • 32/0.20, 1.0mm², 16.5A – cable OD 2.0mm
  • 28/0.30, 2.0mm², 25.0A – cable OD 2.7mm

Which are available in the colour ways that match our bikes harness

32 is the number of strands
0.20 is the diameter in mm of each strand
1.0mm² is the cross sectional area of the copper
16.5A is the nominal current rating of the cable
cable OD 2.0mm is the outside diameter of the cable (so the total diameter including the cable jacket)

For the wire that runs from front to back of the bike (the backbone) use a cable that is rated higher than your fuse value.

This wire will need the current capacity to handle everything it feeds.

I usually select a 12 or 14 gauge cable for this:

Thin Wall Cable

  • 44/0.30, 3.0mm², 33.0A, – cable OD 3.3mm

Photographs showing my loom building can be found on the photo galleries. Its the same starting poing regardless of the machine. I run an earth wire from the front to the back of the motorcyle, and effectively tap into this "Earth Spine" when required.