Author Topic: Wire gauge size?  (Read 256 times)

Offline bake315

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Wire gauge size?
« on: January 11, 2020, 08:34:22 AM »
Howdy folks.

So I found and bought myself yet another truck (this really is a disease), this time a ‘79 K10.  Anyway, I’ve been going through the hatchet job that is the current state of its wiring, and I am going to need to rebuild some of the wiring harnesses. I want to buy correctly matched SXL wiring for each part that needs fixing, and I want to make sure that I get the gauges correct.  The engine harness running up from the starter was pretty badly butchered. Can anyone tell me the gauge size of each of these wires? I have to restore the fusible links (missing) also.

I know I could always buy a new one for that section ready-made, but $200 just seems a little steep.

As always, I appreciate the help!

bake315
« Last Edit: January 11, 2020, 08:37:01 AM by bake315 »
• '73 Cheyenne Super C20 454/400 http://forum.73-87chevytrucks.com/smforum/index.php?topic=7672.0
• ’79 Scottsdale K10 350/NP208/SM465 “Oscar” http://forum.73-87chevytrucks.com/smforum/index.php?topic=37885.0
• ’87 Custom Deluxe R30 350/400 “Felix”

Offline bd

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Re: Wire gauge size?
« Reply #1 on: January 11, 2020, 09:34:55 AM »
1979 Wiring Manual

Wire callout code is wire size in (mm)2 wire color - circuit number (insulation type).  So, 3 PPL-6 (SXL) on the diagram is the 3 (mm)2 purple wire, circuit #6, using SXL insulation.  A metric to AWG wire size conversion table is on page 1; the starter wiring diagram is on page 7.
  • Starter solenoid wire (ckt 6) is 12-ga purple

  • B+ feed to the firewall junction block (ckt 2B) is 10-ga red
    • Ckt 2B is protected by a 6" long, 14-ga fusible link at its starter B+ connection

  • B+ charge lead from the alternator (ckt 2G) is 12-ga red
    B+ feed to the firewall bulkhead connector (ckt 2J) is 12-ga red
    • Ckts 2G & 2J share a single 6" long, 16-ga fusible link at their starter B+ connection

  • the battery cable is 2-gauge

Be sure to use high-temperature loom to encase the wires as they route up along the back of the motor.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline bake315

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Re: Wire gauge size?
« Reply #2 on: January 11, 2020, 09:58:55 AM »
Thanks so much, Rich.  Exactly what I needed and more.  Breaking down the codes and conversions really helps a bunch!

bake315
• '73 Cheyenne Super C20 454/400 http://forum.73-87chevytrucks.com/smforum/index.php?topic=7672.0
• ’79 Scottsdale K10 350/NP208/SM465 “Oscar” http://forum.73-87chevytrucks.com/smforum/index.php?topic=37885.0
• ’87 Custom Deluxe R30 350/400 “Felix”