Electrical Cut-Off Switch

[Mazdahead]

I am adding an electrical cut-off switch and made a copy of the recommended wiring. I noticed something missing as far as I am concerned. There are no fuses between the cut-off switch and the Battery? This is normally a pretty long wire that is routed around the car and could become pinched in an accident and short out against the body. I think it would be very wise to add a fusible link or a fuse right at the battery to prevent this from occuring.
I had a situation last year I am sure Joe will not like hearing about, but here goes.
I had my battery work lose at an event and the positive terminal of the battery hit the hood of the car and shorted out.
This caused the ground to burn off and cause a little problem going up the hill.
When I pulled out my handbrake fire shot out of the handbrake assembly and the choke, E-brake, and throttle cables all burned up.
I assume that they became my new ground path to the battery.
I had to replace all of the cables going to my engine.
I since have layed out my battery area a little better to prevent this from ever happening again!
I am not sure if the fuse would have mattered in this case, but I am going to add one anyway.
In my defense, my brother noticed that something was amiss, but in my hurry to get into line, I didn't think it was anything to worry about.
I was also in a very sickly state and didn't feel like looking under the hood and actually ended up in the hospital for a major operation.
We discussed this and I felt it was a detail we should not have missed, we will always look if anything seems out of the ordinary from now on!
I Hope my escapades may help someone avoid any occurances like this so they don't experience a similar experience.
So, when Joe tells us to shake the battery, this is a good example why to do it!
I hope I didn't get myself into trouble with Joe from posting this? lol

[timurf]

Yeah, don't remind me. My head still aches from inhaling the fumes of burnt electrical-grade varnish and vinyl insulation!

Of course this is sage advice on how simple details can prevent catastrophic situations. On my cutoff switch I routed the wires through grommets where it goes through the body and secured wherever possible.

At least I think I did - better add this to the pre-race checklist...

[Joe Foering]

You certainly did NOT get in trouble for posting that message; if nothing else, it shows how important it is to SECURELY fasten down the Battery and insulate the positive terminal! As to the fuse, if the aforementioned is done, it shouldn't be necessary , but I don't see where it would hurt. Any other comments from anyone?

[Mwilson]

Your battery should have a cover over the positive terminal. If you don't have a cover some racing tape will work just fine. In the event that the battery does come loose your chances of getting a short are greatly reduced. I also have a cover over the positive side of my kill switch. An ounce of prevention is worth a pound of cure. Also any spare batteries you may carry in or on your trailer should have some type of cover. Just a few suggestions that cost penny's to do but may save you some costly repairs down the road.

[RX-Midget]

Covers and insulation are the right thing to use, but when I built my car I was thinking that it doesn't take much to cut through the insulation on the wire if in a wreck. I added a 100 amp circuit breaker just about 3 inches from the battery positive terminal. The breaker was avalible from many car stereo shops or on line. I have never popped it while cranking the car over, but I know that the battery and cables will exceed the 100 amp rating if there was ever a dead short and hopefully it will prevent a total melt down.

This is like the one I used:

http://www.wiringproducts.com/contents/en-us/d29.html