I bought a wiring harness for my truck from Rhode Island Wiring a number of years ago . Its a high quality product and has an inline fuse holder in most every individual circuit. I am not sure what fuse amp rating I should use in any of these individual circuits. Can anyone help me out - I received no documentation from RIW. ?

What are the circuits in question??

Hi JYD

Rhode Island make a better fused wiring harness
I guess I could put a 30 amp bus in each circuit, measure the amps that each circuit draws and choose a say 150% as the rating. I don't think it is that critical. You are just trying to prevent the wires from melting when shorted.

The circuits are:

ammeter discharge
horn button ground

driver rear stop & turn
driver and passenger rear tail
driver front turn

passenger rear stop and turn
passenger front turn

fuel tank

Thanks
John

Well push comes to shove the fuse is a safety point (weakest link) that saves the rest of the system.

With the circuits you posted I would think 10 amp fuse would be a reasonable choice for all except the horn at 15 amp. The ampmeter may well be prior to the rest so might require 25 or 30 if not 10amp may be sufficient.

Tony