Coil Relay Wire Sizing

[MisterCinders]

I am looking into this mod. The various threads on this call for 12g wire for the power and ground connections. All of the relay pigtails that I find, however, have 14g wires.

This raises two questions:

First, should I still use 12g wire for the runs off the pigtail?

Second, if so, what fuse should I use for the power connection and where should I place it?

a. Set the fuse for the 14g wire and install the fuse at the pigtail end;

b. Set the fuse for 14g and install in the main wire line, closer to the power source; or

c. Set the fuse for 12g.

I am leery of basing the fuse on the thicker wire, when there is thinner wire within the run. Don't want any part of the wire to get hotter than the break point on that fuse -- i.e., the 14g getting too hot but the 12g wire and fuse not tripping. All things being equal, I think 14g wire and fuse would be safest. What do you guys recommend?

[mike_of_bbg]

Unless you've modified the ignition system, 10A is all you should need for the fuse. It's what Suzuki used. I used #14 stranded copper for mine.

[Nessism]

16 gauge wire is enough, no need for anything bigger unless it's more convenient for you.

[FiremanBob]

I used 14g because I had a supply of both wire and connectors handy. As I learned during my mod, the coils don't draw a large amount of current, so heavy wire is unnecessary. If you look at the OEM wiring, it is actually thinner than 18g.

[posplayr]

Unless you've modified the ignition system, 10A is all you should need for the fuse. It's what Suzuki used. I used #14 stranded copper for mine.

That is the fuse for the stock ignition circuit, 10A.

[Suzuki_Don]

That is the fuse for the stock ignition circuit, 10A.

Yes Jim - AND . . .

[Steve]

If you are running separate wires from the relay to each coil, 18ga would be plenty.

Each coil draws about 3 amps. Technically speaking, a 22ga wire will carry 5 amps over the short distances involved in our bikes.

A 16ga wire will handle four times that, or 20 amps, over short distances.

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