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Old 09-01-2017, 07:46 PM   #1
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Ground wire sizing

I am almost done wiring my LS swap in my '85 C10. I have the grounds for the ls harness hooked up. I was wondering if 12 guage wire is enough to ground the motor to the firewall and to the frame?
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Old 09-01-2017, 08:35 PM   #2
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Re: Ground wire sizing

probably...but I bought one of those flexible braided ground straps for mine...
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Old 09-01-2017, 09:12 PM   #3
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Re: Ground wire sizing

The exact same current that flows on the plus side flows back to the source on the negative side so both need to be the same. Or rather, both need to be larger than the needed to feed the load. The point is the delivery system (wires) shouldn't be the limiting factor.
You also need a fusible link/fuse/breaker on (typically) the plus side to prevent smoke in the event of disaster.

Last edited by franken; 09-01-2017 at 09:34 PM.
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Old 09-03-2017, 11:05 AM   #4
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Re: Ground wire sizing

If your primary negative battery cable goes to the engine block, then the ground straps from block to frame and cab can be smaller. I think the block to cab strap on my 75 roughly equates to a #8 wire and my prime negative cable connects to the alt bracket on the engine.

If your main battery cable goes to the frame, then you need a matching size cable from frame to block. Otherwise your undersized ground strap might go poof when you try to start it.
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Old 09-05-2017, 09:39 AM   #5
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Re: Ground wire sizing

Punished you have pictures of your work?
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