Cable cutters to stop starter run on?

[iacucv]

Hey guys, I've been lucky and have done the Dog head mod, but a 1008 I sold that had Doghead mod done had starter runaway and now I'm trying to prepare for it. I recently purchased a nice Mac plier/cutter set and it came with a cable cutter I will likely never use. Made me wonder what would happen if a guy tried to cut the ground cable during that kind of current draw or if anyone has done it? Possibility of melting some tools but much faster than loosening terminals. Any experience or thoughts? Thanks guys.

 

[tobyS]

Good luck cutting it under what is next to a fault condition that could be hundreds of amps. It reminds me of cutting a 3 phase 208 all at the same time live.


I would consider a second solenoid in series myself, switch activated.

 

[cucvrus]

With the stock set up if it ever happens I just reach up and upplug the relay. But cutting the ground would do the trick. Not like you would get shocked by cutting a ground cable. Am I missing something about the 3 phase 208? I don't see how anything cut happen. If worried why not a breaker in the line. Never dove that deep in. Just kept srtrong batteris and a good starter with a good running CUCV. Good Luck.

 

[tobyS]

The 208 was my only time taking a real shock in many years doing heavy electrical. The idea of cutting a "run away" starters wire brought the thought back to me.

I'm probably way off base...maybe it would be like a pulling a welding ark and not have the explosive effect that I envisioned.

 

[antennaclimber]

Been there done that. Cut the little ground wire first then the big wire.

It can be done but only as a last resort. Keep the cutters in the glove box.

 

[cucvmule]

All I do is keep the neg cable snug enough to pull off in case of runaway. I will place inline battery disconnect switch at some point. They cost from 20.00 bucks up to 130.00. I just replaced the relay with new one even though the one that was there looked new anyway. Do not overtax the relay by continuous cranking and it will last a long time. Keep cables clean and in good shape.

 

[Guyfang]

With the stock set up if it ever happens I just reach up and upplug the relay. But cutting the ground would do the trick. Not like you would get shocked by cutting a ground cable. Am I missing something about the 3 phase 208? I don't see how anything cut happen. If worried why not a breaker in the line. Never dove that deep in. Just kept srtrong batteris and a good starter with a good running CUCV. Good Luck.

You are correct. Cutting a ground or Neutral wire is safe. Nothing should happen.

Cutting a 3 phase cable is something different. Cutting a Positive or a cable that is phase, normally causes you to go buy a new cutting device. The damage occurs when the cable separates from the cutter. The Volts/amps try to jump that gap, and its will ruin your cutter. Or put a gap in the blade, that later makes you mad, because when you try and cut something else, the cutter will not cut completely through.

But when its a 3 phase cable, the light show can be much bigger. In theory, the cutter can come in contact with all 3 phases, at once, depending on the shape of your cutter jaws. If your cutter has no insulated handles, or you are not wearing the PPE, (proper Protective Equipment) you can have a Significantly Emotional Experience. And if the cable is under load, you are in the big boys league. Most of the time, if you are on the output side of a protective device, (fuse, circuit breaker) you don't have to worry TOOOOOO much. But if you are on the wrong side of a large protective device, things are much different.
I once darkened a small town. Its a funny story I tell now. Wasn't funny then. I blew two 416 amp fuses in the transformer station. Was blind for 45-60 minutes. Didnt need new underwear, but it was close.

 

[doghead]

DC power. Tell me why the negative cable does not carry the same amp load as the positive cable?

3-400 amps will hurts you, AC or DC.

 

[Guyfang]

DC power. Tell me why the negative cable does not carry the same amp load as the positive cable?

3-400 amps will hurts you, AC or DC.

I didn't say Negative. I said NEUTRAL. AC. I once cut a Neutral, in a very large warehouse. Lots of things running. The only thing that happened was that the lights went out. Now a Negative, that's a horse of a different color.

 

[tobyS]

I was finishing a demo job and until that time, all the electric had been dead. I was in a bucket about 30' up with one hand on a steel truss and the other on my cutters. I got all three phases at once + neutral in one hand and out the other.

I've had electricians licence for (edit)45 years. At Square D Company I wired 4000a devices for UL heat rise tests and ran them til they could cook on them. Our engineering group had slow motion video of devices being blown apart (to improve design or find weak spots), so there are few people with more respect for electricity than I have. Sending 80,000 amps (RMS) through a device for 4,000 is as close to a nuke explosion as I would ever want to be.

I'll leave the cutting of a wire passing 200-400 amps to guys with more guts than I have. Maybe the DC thing would make it harmless, but not something I would try.

As far as the 208, I could not let go of the either the cutters or the steel frame but had the presence of mind to pull, using the contraction of the elbow mussel to get away from it. You are entirely right Guyfang about crossing phases + neutral....it's bad.

 

[cucvrus]

I have done it on 12volt DC Liftgates, electric hoists, winches and never had any ill side effects. When DC electric motors are stuck and smoking hot I cut the cable. With out the positive and negative involved at the same time it is just a wire. I cut a few CUCV cables that were stuck on starter run and smoking. Snip and done. Not something I do on a monthly basis. But being around vehicle business for 40 years its been done at accidents all the time. SNIP. Have a Great Day. Be Safe.

 

[tobyS]

I know what you are saying about it being a mechanical thing because you are not part of it's circuit, you are not the negative aka "ground" of the vehicle. But you could have become part of the circuit if you had the clippers in the right and have your left hand on the vehicle steel. That is what I did, be it at a higher voltage.

The other factor is your electrical connection to your cutters. If you have insulated grip cutters or gloves, your probably good also. If your like me, you were not lucky that day to be using your insulated pair. The steel ones cut so nice, but had no insulation at all.

If you are ever cutting the wire under load, don't make yourself part of the circuit by holding on to some part of the truck with the other hand.

 

[Guyfang]

When I cut the neutral, I made the biggest mistake anyone will ever make. I trusted someone I didn't know. I was cutting out cables that were not needed anymore. Factory renovation. I was in a more or less dark room, and asked someone upstairs to pull on the cable that needed to come out. A cable moved, I cut it. No big deal, just that the one light in the room went out. Of course, everyone and his dog was mad at me. A kazillion computers went down, server went down, the conveyor belts stopped and on and on. No happy faces.

When I blacked out the town, I made almost the same mistake, only I trusted my boss. I knew he was wrong, and trusted him anyway. Was I ever, a fool.

My son does this kind of work all the time,. Cutting and splicing under voltage. They have the right gear, and training.