what size fuse to use.

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Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=136469
Printed Date: April 28, 2024 at 7:34 AM

Topic: what size fuse to use.

Posted By: kassdog
Subject: what size fuse to use.
Date Posted: April 17, 2014 at 3:51 PM

So getting ready to figure out fuse sizes for running new wire on this Porsche kit car.

When figuring amperage it watts/volts. So if my bulbs for the headlights are 55/60watts the my amperage is worse case 5.5 amps and 6 amps.

For some reason I've always assumed headlights had a higher amperage rating.

Then using a wire gauge chart I should be fine running 16ga for my headlights. Just trying to get someone to back up my numbers.

Replies:

Posted By: the12volt
Date Posted: April 17, 2014 at 4:19 PM

You should always fuse for the wire and not the lights or any other component. Have another peek here:
https://www.the12volt.com/wiring/recwirsz.asp

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Posted By: the12volt
Date Posted: April 17, 2014 at 4:35 PM

BTW, I should have said "You should always fuse for the smallest wire in your circuit and not the lights or any other component..."

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Posted By: howie ll
Date Posted: April 18, 2014 at 1:52 AM

Incidentally there will be extra power consumption via relays etc, so bump that 6 amps to 10.
Back in the (audio) day if an amp carried a 30 amp body fuse, we placed a 40 amp at the battery end.
Also rate your wiring for the load there are charts available if you Google wire gauges or similar.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Posted By: oldspark
Date Posted: April 18, 2014 at 7:46 PM

And fuses - like cables & relays etc - should generally only be run at up to ~70% of their rating. (But some components are underrated to begin with...)