# Fuse Rating



## Rodsih300 (Apr 4, 2014)

My 1955 IH 300 does not have the fuse holder on it and the light switch has had all of the wires cut. I am putting things back together and I can't find out what the amperage rating of the fuse for the lights is supposed to be. Hopefully, one of you can help me.Bye


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## jhngardner367 (Apr 5, 2011)

Usually , it is determined by the system voltage,size of the wire,load,and length of run.
Most lighting systems will have 12vdc,12ga wire,and 55w(max) lights,and carry a 15amp fuse.
A good comparison is to look at a car/truck system,and copy it.
If you have a 6vdc system, the same applies,but use a 10 amp fuse,to protect older wiring.


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## film495 (Nov 1, 2013)

depending on the type of fuse, usually they are cheap. I've done this and just started with a low rated fuse, and worked my way up until the fuse didn't pop right away; this is my fasted way to do this if I just want it done so i can move on.

to be more scientific, watts/volts = amps I believe. So, if you have 2 headlights. figure out their watts, divide that by the volts, and you'll know the draw required to power the lights. Pick a fuse slightly higher than the required draw - if you can't find a manual or schematic that shows the spec. Technically, I think a fuse is rated by the gage wiring it is supposed to keep from melting, but often they are larger than they need to be in my view; but, if you don't know the spec you're likely better to err on too low a rating than too high. 

I think my lights are 35 watt, makes 70 total, at 12 volts; comes out to a little under 6 amps. I think that fuse also protects the tail lights which are small, but I think it has a 15 amp fuse. It would likely work fine with a 10, and it wouldn't hurt anything.


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## Rodsih300 (Apr 4, 2014)

Thanks gentlemen. I Found the fuse holder and the right size fuse at a marine supply shop. I am putting it in today and will give it a real test when my replacement headlights arrive.


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