[TXSTARFIRE]

How does higher heat insulation increase ampacity?

[Shiny]

Resistance/ft does follow the wire gauge but "Ampacity" is limited by heat dissipation. If the insulation can tolerate more heat, the wire can "safely" run hotter without melting/degrading the jacket. Doesn't mean it's smart but that's the argument. It's a rating thing.

Margin is your friend, especially when the load's performance is sensitive to voltage (like a starter motor).

[73ta]

Originally Posted by TXSTARFIRE

How does higher heat insulation increase ampacity?

Its per the NEC national electrical code. It can carry a higher amperage with a higher rated insulation. You also derate the amperage for ambient heat, length of runs and wire fill in conduits.

[HWYSTR455]

GM (and other US OEs) use GXL, TXL, SGT, and SGX wire in new cars and commercial vehicles.

Here's the GXL/TXL AWG recommendations and the battery cable AWG/AMP/Feet chart.

Also, here's the GM Electrical Best Practices doc, if you want to review it:

https://www.gmupfitter.com/wp-conten...rac_093017.pdf

Just to say, NEC doesn't provide guidance to the auto industry, although some principals apply.

SAE & NHTSA regulate automotive stuff, you can read their' docs if you really need to take a nap.


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