What size/type fuse to go from Alt to fuse block in Ls swap? [Archive]

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cpd004

02-19-2015, 05:35 AM

I'd like to put some type of fuse in line between my alternator and the fuse panel. I'm not sure what size fuse and what type would be best. It's an Ls3 in a 71 Firebird that had a Painless muscle car harness put it in at some point. I'd also like to be able to pull power from one side of this fuse for the fan's. The fan wiring has it's own fuses in line. Any suggestions would be appreciated.

gerno

02-19-2015, 10:22 AM

My painless harness came with a large 50 amp fuse I have mounted on the firewall.

rickpaw

02-19-2015, 04:23 PM

I've seen some pictures where the car audio guys put in 100A resetable breaker.

cpd004

02-21-2015, 04:46 PM

Thanks for the replies.

Black93GT

02-27-2015, 09:06 AM

The key is sizing the fuse appropriately for your wire. 100a on a 10ga wire won't do so well. I didn't find a chart an SAE or UL chart for automotive ratings, but here's one from the coast guard that would be right in line with other agencies.

USCG DC Wire Selection Chart (http://assets.bluesea.com/files/resources/newsletter/images/DC_wire_selection_chartlg.jpg)
https://www.bluesea.com/files/resources/newsletter/images/DC_wire_selection_chart.png