Wiring help

[Pandersen33]

Had a small fire today as a result of what appears to be a jammed brake light switch. Snowballed into the alternator wire and up into the terminal. Anyways i was trying to figure how how to prevent this in the future. Specifically if anyone has had luck using in-line fuses and if so what size? So far it looks like i’ll just be needing some new wires and a brake switch. Thankfully i had JUST put the fire extinguisher in the back of the car!

[midgetracer]

I like the safety fuse that mounts on the starter. It usually has a 20 or 25 amp fuse and is a fail safe when you have a short that might burn the car up. I know some don't like it, but for about $10 it provides a way to keep the wiring from burning up the car in a dead short situation.

[31 Vicky]

And install the A&L brake light switch.
The other available switch can fail by shorting to ground!

A's Always Dave

[Y-Blockhead]

Originally Posted by midgetracer

I like the safety fuse that mounts on the starter. It usually has a 20 or 25 amp fuse and is a fail safe when you have a short that might burn the car up. I know some don't like it, but for about $10 it provides a way to keep the wiring from burning up the car in a dead short situation.

Our club just had the second wiring fire this year. I have given several of the safety fuses away at our monthly meetings... People just don't get it.

I run a 30a circuit breaker for my main fuse and a 20a on the lighting circuit.

[Y-Blockhead]

Duplicate post...

[Synchro909]

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Does the fuse on the starter cut power to the ignition if it blows? If it does, I'm not in favour. It's not hard to imagine a dangerous situation quickly arising if it were to blow on a busy road and the motor goes dead. I believe the ignition should not be fused but all else (except the starter!!), yes.

[katy]

I run a 30a circuit breaker for my main fuse and a 20a on the lighting circuit.

Ditto

[Ed Wendell]

Originally Posted by Synchro909

Does the fuse on the starter cut power to the ignition if it blows? If it does, I'm not in favour. It's not hard to imagine a dangerous situation quickly arising if it were to blow on a busy road and the motor goes dead. I believe the ignition should not be fused but all else (except the starter!!), yes.

If I had an electrical fire on any road, busy or not, the motor stopping is the last thing I would worry about.
I use the fuse mounted to the starter. I park our car in a cargo container and want to make sure everything is dead so I installed a battery disconnect switch.
Ed

[Pandersen33]

How are you isolating the lighting wiring from the main? Im assuming the 30a fuse is the safety fuse setup on the starter.

[cpf240]

Originally Posted by Pandersen33

How are you isolating the lighting wiring from the main? Im assuming the 30a fuse is the safety fuse setup on the starter.

Probably a fuse at the generator cutout where the lights and horn get their power.

[Badpuppy]

Originally Posted by cpf240

Probably a fuse at the generator cutout where the lights and horn get their power.

A 20A fuse at the cutout to the lighting switch and horn will open those circuits if a short occurs. The fuse mounted on the starter is intended to prevent the battery from discharging into the generator field through a shorted cutout after the engine is shut off. if either or both fuses open during operation, the ignition will still be powered from the generator.

[Roadster62]

That is the impossible thing about understand electricity, nobody explains things the same way. Bob

[Y-Blockhead]

Originally Posted by Pandersen33

How are you isolating the lighting wiring from the main? Im assuming the 30a fuse is the safety fuse setup on the starter.

Originally Posted by cpf240

Probably a fuse at the generator cutout where the lights and horn get their power.

That is correct. The wire coming off the alternator to the lights/horn is fused with a 20a circuit breaker. The circuit breaker is "hidden in the frame rail by the alternator.

[dansluck]

I have 30 amp at starter and 20 amp at cut-out. Thanks Pandersen there has been some great responses.

[DHZIEMAN]

The Model A I purchased had a short in the headlight circuit. Burnt up low beam wiring. Replaced it and then,
I installed a fuse block and 30A Fuse at the starter. Works fine!
Also double checked all wiring to make sure all was working and properly wired.

[Jacksonlll]

I always put an inline fuse in the brake lite switch because if there is a problem, it is a long way under the car to get at it on the road.

[ArtimusGordon]

I use a 30 amp ckt breaker on the starter and I also installed a battery cutoff switch in front of the drivers seat. I also lost my coupe to a wiring fire a couple of years ago. (You can search for pictures on a previous post ( search “ SAD DAY” ) .

[ArtimusGordon]

Originally Posted by ArtimusGordon

I use a 30 amp ckt breaker on the starter and I also installed a battery cutoff switch in front of the drivers seat. I also lost my coupe to a wiring fire a couple of years ago. (You can search for pictures on a previous post ( search “ SAD DAY” ) .

Try in search “fire”. Scroll down to “Sad day” for pictures of my totaled Coupe. 😠

[TJMack]

I had a couple issues with my brake light switch when I first got my coupe. You might find this thread interesting. just paste it into your search bar. it will take you to the thread.


https://www.fordbarn.com/forum/showt...e+light+switch

[slammin]

Originally Posted by Y-Blockhead

I run a 30a circuit breaker for my main fuse and a 20a on the lighting circuit.

Even though all the wiring is new, I took the same approach. Plus I added a battery disconnect under the drivers seat. When I pull the car inside, I shut off the gas and throw the disconnect switch. Prior to adding the switch, I pulled the battery ground cable.