Pre-war (up to 1942) 1936 wire gauge

[Dennis Rizzuto Jr]

1936 Cadillac wire gauge (thickness): I want to replace some of the wiring in my 36 Fleetwood, not much but some of the wiring in the engine compartment, especially the horn wires, are in very poor condition. When reviewing the 1936 Shop Manual, there are numbers next to the wire color abrasion in the schematic. I'm assuming this is the gauge for that particular wire but want to make sure. Most of it appears to be 14, and 16. The quality of manual could be better, it is a reproduction. Any info or pointers would be great.

[Brad Ipsen CLC #737]

Yes, that is exactly right.  As you can see in the diagram the main line is 10 and there is a little 12 present.  Also, the 36 diagram gives the colors all in one diagram.  This is much better than some in later year shop manuals.  If you want an original shop manual in near new condition except for the cover, I have one for sale.  brad@ipsengarage.com

[Dennis Rizzuto Jr]

Hi Brand, thank you for confirming that for me. Do you know where it would show how many amps each circuit is? I'm going to add some inline fuses or a fuse block. I think I'm good with the manual I have, what are you asking for yours? Thank you again.

[Chopper1942]

Fuses are designed to protect the wire in the circuit. On some circuits the fuse protects the device like a radio.

The rule of thumb for fuses to wire gauge is:
     
    Wire Size:      Amperage: 
                   
       8               35     
       10              25
       12              20
       14              15
       16              7
       18              5
       20              3

                             Applications of Wire

        Wire Size 6-Volt     Wire Size 12-Volt             Item
                 8              10                   Ampmeter gauge
                 8                 10                   Alternator or generator and regulator large terminals
                 12              14                   Electric fuel pump
                 12              14                   Headlights
                 12              14                   Alternator or generator and regulator small terminals
                 14              16                   Gauges, fuel, oil, temperature
                 14              16                   Ignition, distributor, coil
                 14              16                   Directional signals, parking and tail lights, and radio

Often a device will be fused for less current than the amperage capacity of the wire going to it.

Personally, I would install a small auxilliary fuse block with modern ATO/ATC fuses.

Divide the inputs to the fuse block into Hot at all times, headlights, tail lights, etc. and hot only when the ignition key is on: radio, gauges, heater, ect.

Any splicing of the wires should be done with heat shrink butt connectors.

Hope this gives you some guidance.

[Dennis Rizzuto Jr]

Thank you Larry, also very helpful