Ignition switch, fused or not?

[36tudordeluxe]

Have a 12V system, alternator with internal regulator, stock '36 ignition switch, starter button located on dash and fuse panel. Ignition switch is now wired direct to battery, would I be wise to fuse this circuit?

[tiger.1000]

Without doubt !

[V8COOPMAN]

Why would you not feed the IGN switch from a dedicated fuse in the fuse panel? DD

[Mart]

There is not normally a fuse in the ignition circuit. (Old fashioned ones anyway, not sure about modern stuff)

Mart.

[V8COOPMAN]

Lots of truth to what Mart says. The main reason for fuses is to protect WIRING...not electrical gizmos that are powered by that wiring. DD

[36tudordeluxe]

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The wiring diagram I referred to didn't show a fuse. I will wire it through the fuse panel now. Thanks everyone for the help.

[325w]

Most after market wire harness don't have a fuse for the switch.

[russcc]

If you don't have a negative side battery switch, that is a good safety measure to think about, especially with a push button starter. Shut off the switch, and there is no power anywhere. Cole Hersee in Boston still making the best switch.

[B-O-B]

I used a painless harness on my 32 & it has a 50 amp master fuse in the beginning of the system .I also use a Cole Hersee master disconnect switch.

[oldford2]

Originally Posted by Mart

There is not normally a fuse in the ignition circuit. (Old fashioned ones anyway, not sure about modern stuff)

Mart.

So ,if it is a good idea to put a fuse in the line from battery to ignition switch, what size should it be?
Thanks
John

[36tudordeluxe]

I do have a 50 amp switchable fuse now. Am thinking 10 amp fuse for the ignition circuit?

[Mart]

I would not put a fuse in the feed to the ignition switch. The feed from the switch to the ignition system should not be fused.
The feed from the switch for anything else can be fused.
The feed from the battery side of the switch for stuff that works without ignition (lights for example) can be fused.

No fuse in the ignition as such.

Mart.

[donald1950]

no fuse from the battery and no fuse going to the coil....... all the accsories, yes fuse them AFTER the switch.....

[BILLF/TRF]

In the EZ Wiring guide, the use of a fusible link (or Maxi, Magnum Fuse by Ron Francis) is required or the warranty on the harness system is void. There is normally a 10 ga. wire from the battery through the ammeter through the fuse block to the ignition switch. The wire is called battery or solenoid power wire and it is where a fuse would be located. There is not a fuse in the fuse block for this circuit.

[rotorwrench]

While the system max ampere rating is usually 35 amps for these old cars, the fuse ratings are and always have been related to wire size as V8COOPMAN mentioned earlier. The minimum fuse size for a 10-guage copper wire is 30 amp. You can use a larger one but keep in mind that you are protecting the wire from burning and catching itself and others on fire. An 8-guage wire has a minimum fuse size of 50-amps and they just get bigger from there on. Many of these old cars already have a system circuit breaker but it is mounted to protect wiring after the bus but not before. The starting and charging systems remain unfused.

Most folks just use either a master cut off switch or disconnect at the ground strap on the battery. If the wiring is maintained in good condition, a person shouldn't have to worry about a fire but having a procedure for disconnect is the safest thing a person can do. If a fire happens after that then it isn't the wiring at fault.