Fusible Link

[Audengineer]

Hello All,
I am looking for some help, I want to put a circuit breaker on the positive line off the batterie before the starter solenoid and was wondering if anyone knows what size circuit breaker I should use, I have a mid 90's EM cobra with a stock 351c in it. Any help wold be greatly appreciated.
Thanks

[Rick Parker]

Ad up the amperege used by ALL of your electrical items except the starter IE: Headlights on High Beams, Fan, Ignition Radio, Running lights, etc add them all together and get the next higher rated Fusable Link. Runn all curent through this wire. If you experience a short circuit somewhere it will generally exed this rating and burn the fusable link. Individual circuits can have regular fuses in them as well (fuse box).

[Barnsnake]

If you want it to protect the battery cable itself it will need to be huge. The starter can pull a surge of 900 amps or so. As I remember they settle back to 300-400 amps when cranking.

[philminotti]

Usually most systems have a 200A megafuse between the alternator and the battery. I've never seen a fuse or breaker between the starter and the battery. I'm not sure i understand what you'd be trying to protect....anyway, like barnsnake said, it'd have to be one hell of a fuse, for sure.

[Audengineer]

I have heard of people having their solenoid get stuck and burning the positive wire back to the batterie and starting a fire. If there is a better way of doing this I am open to ideas.

[Jaydee]

Having an accessible battery isolator switch is probably more reliable. I have seen a starter short out and go red hot, the battery nearly melted. but luckily it didn't start a fire. At least you'd be able to isolate it quickly.
JD

[Audengineer]

Thanks JD, I do have a shut off switch and I thought the same thing, but I wasn't sure if that was the best way to go about it. My buddy had pointed it out and thought it was odd that there was no kind of fuse or breaker in line so I thought I would start asking around.

[philminotti]

I see your point. Fortunately most starter failures are of the open circuit variety, but it is a concern especially considering the quality, or lack therof, of typical aftermarket products.

[FWB]

Originally Posted by Audengineer

Hello All,
I am looking for some help, I want to put a circuit breaker on the positive line off the batterie before the starter solenoid and was wondering if anyone knows what size circuit breaker I should use, I have a mid 90's EM cobra with a stock 351c in it. Any help wold be greatly appreciated.
Thanks

i use this on my firewall for two purposes, 1st for circuit protection, 2nd for a lug to pull power so everything doesn't go to the alternator or starter.
made by Bussman.....

you can put a blade type fuse (AMG) mounted to the lugs...i think i have a 200 amp on mine.

[Rick Parker]

Cole Herse makes nice resettable circuit breakers that attach to firewall with two screws and have two 10-32 studs for attaching wires. These can be had at NAPA stores and others places too. They work quite good. I use 40 amp one for my application. I just have lighting, ignition and relay for fan and horn running through it, no radio etc.

ERA uses these and can be seen mounted near the starter solenoid on firewall near passenger foot box.

[FWB]

Originally Posted by Rick Parker

Cole Herse makes nice resettable circuit breakers that attach to firewall with two screws and have two 10-32 studs for attaching wires. These can be had at NAPA stores and others places too. They work quite good. I use 40 amp one for my application. I just have lighting, ignition and relay for fan and horn running through it, no radio etc.

ERA uses these and can be seen mounted near the starter solenoid on firewall near passenger foot box.

i was going to use those Rick.....the 10-32 lug is what turned me off.
the bussman has 1/4 inch lugs. takes a #2 cable easily....

cole-hersee has some nice stuff, i use their indicators and switches on my dash...and they are the go to place for ford type starter solenoids.
little-fuse owns them now

[Audengineer]

Rick is that 40 amp breaker before the solenoid and starter?

[Audengineer]

FWB do you have an opinion about the Bussman 148-CB185150, it is only 150 amp and it does cost a bunch more than the one you are using but it is a circuit breaker rather than a fuse. I am concerned that the draw from the starter will cause it to trip with it only being a 150 amp breaker.

[Jaydee]

As long as the main wire from the battery to the solenoid is insulated and bolted properly, it is unlikely to ever short out. As long as the cable is heavy duty enough that if the starter got jammed, it would just keep winding { therefore you turn of the isolator] or if it shorted, the battery woulod die, before the cable will catch fire. So therfore, you really only need a 100 amp main fuse to the entire system after the starter. And obviously smaller fuses to individual items. Slightly of the subject. I made a anti theft device on the principle of a short. I coiled a thin telephone cable inside a bacolite tube with small holes and wired through a hidden switch. So if someone hotwired the ignition, it would instantly short out the wire creating a lot of acrid smoke, enough to scare of the thief. It only drained about 2 amps and would go open circuit very quickly. Only too bad if you forget to turn it of. But you could wire it to a light on the dash.
JD