Power Steering Fuse Advice

[kraftee]

I have a question about proper fuse sizes. The "Official FFR Hot Rod Assembly Manual" says, "Connect the green wire to a switched +12 volts. This can be done by either running a wire directly to the key or, if running an EFI car or Carb without electric choke, the tan “electric choke” wire can be used." So, I wired the "switched" green lead from my power steering to the tan electric choke lead (since I am running an EFI car.) Of course, the manual notes that, "If an existing circuit is used such as the “electric choke” for something other than the original purpose, make sure to note the new function on the fuse panel and also make sure the correct fuse size is used." So, I relabeled the choke fuse as power steering. It is a 10-amp fuse and tonight that fuse blew. Of course, fuses don't protect electrical equipment, they protect wiring. And since we are using the same tan wire - I assume 10 amps should be "...the correct fuse size." What do you think? Isolated occurrence? Or do I need to wire directly to the key switch?

[Just puttering]

Fuses protect the equipment also, the fuse is there so the wire has a weak link and you dont melt or burn up the wires which happen when the component draws to much current. You could have the same size wire with different amprage fuses depending on what the component draws and what safety factor is needed. Find out what fuse is called for on the power steering. Also did it blow after running awile or when powered on. Check all connections for shorts or bad grounds. If you change to the switched 12v what fuse does it have? Moving to the switched wire may just blow a different fuse!
I would try to keep it on its own circuit (choke wire), a blown fuse is a good thing compared to not knowing and melting a wire harness!

Good luck

[Tampa33Build]

Tom,

Fuses need to be matched to the wire gauge also. Without a schematic of the power steering module I have to believe the green wire is only to activate power to the power steering box. The red wire supplies the power along with the black return wire since the red wire has a 30 amp fuse it and should be a 10 or 8 gauge wire to handle 30 amps. The current capability of a wire depends on the wire gauge and number of strands. The lower the gauge and the less strands the more current capability of the wire. The green wire looks to be about an 18 gauge and most likely has 7-24 strands of wire. If so it is rated at about 5 amps. A ten amp wire would require a 14 gauge with 7 -24 strands or 16 with three or less strands.

Neil