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I am going to put a fusible link between my ignition switch and my heater switch. The auto parts stores carry two versions. One model has a choice of 12 ga - 30 amp or a 16 ga - 15 amp. There is also another model with 14 ga wire and the choice of a 20 amp or 30 amp. The truck is 12 volts and the heater motor is also 12 volts. The heater switch is one of those universal 3 position units. Any suggestions would be appreciated.
Bill

Bill,

Get ready to get confused. The motor on your heater pulls about 6 amps I think. So if you put a fuse in the circuit, you would use a 15 amp fuse. This would cover the fan motor for 150% and protect wire as small as 16 gauge.

You say you are going to install a fusible, and not a fuse (??) so the same would apply. If you go techno-nuts, you will see that the ampacity of the fusible link is tied to the wire size, not the device being protected. To get net, pick any size the equates to 150% of the full motor current...6 amps X 150%= 9 amps. The closest fusible link is the 16 gauge @ 15 amps. That would be your choice....why not a good old fuse?


Stuart

agree w/ Stu, easy to get an accessory in-line fuse holder and add it in the line to the heater

Bill

www.madelectrical.com has some very informative information on this subject.

I may have erred in saying I was putting in a fusible link. I meant to say I am going to put in an in-line fuse, one of those little nylon units that snap together with a separate fuse. The wire gauge and ampere I wrote about referred to what is available in those units. So to sum up, a 16 ga wire with a 15 amp fuse should suffice, correct?
Bill

Bill,

Perfect. Put it between the power source and the little heater switch and it will protect both the motor and switch in the event of a problem.


Stuart