Thread: Master power switch. Electrical GURUS needed

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Originally Posted by 34_40

My point exacty! Every time the circuit becomes complete an arc will occur! It doesn't matter if it's + or - ! Consider an arc welder, it can be positive ground or negative ground. There will still be an arc when the circuit becomes complete! Don't believe me? Fire up you stick welder, clip the electrode holder to the steel and clamp the ground to a rod, yes, you can still weld with it! the circuit will be completed! And don't ask me how I know this! I guess I can be silly to prove a point!

If you plan for the circuit to stay isolated you will be prepared! I like the breaker idea too!

I must be getting brain farts..are you saying that if I went out and disconnected my negative battery cable from where it is mounted to the frame, and then tapped the frame with it, I would still get an arc? I would have thought that I would have to actually touch a positive wire to accomplish that. I can't see how a circuit would be completed, with a ground to ground contact.

Now on the other hand, if I disconnected my positive cable say from the starter, and then started tapping the frame, or any other grounded point, I know I would get arcing.

Originally Posted by Chev malibu

I must be getting brain farts..are you saying that if I went out and disconnected my negative battery cable from where it is mounted to the frame, and then tapped the frame with it, I would still get an arc? I would have thought that I would have to actually touch a positive wire to accomplish that. I can't see how a circuit would be completed, with a ground to ground contact.

Now on the other hand, if I disconnected my positive cable say from the starter, and then started tapping the frame, or any other grounded point, I know I would get arcing.

Yes! Go ahead and remove the ground connection. Now turn on the headlights then touch the side of the connector to the post and watch for a spark. it'll be there as the current has to flow when the circuit is completed.

Originally Posted by 34_40

Yes! Go ahead and remove the ground connection. Now turn on the headlights then touch the side of the connector to the post and watch for a spark. it'll be there as the current has to flow when the circuit is completed.

Your absolutley correct,but it will not be to the same extreme as the positive cable breaking and shorting to ground.

Originally Posted by HWORRELL

Your absolutley correct,but it will not be to the same extreme as the positive cable breaking and shorting to ground.

In any event, the original question was it do-able! Due to the ease of installation - for him to use the negative. My answer would still be yes.

Do-able and should I do-able are two different things. It is do-able to jump off a cliff, but......................................

Sometimes you just do things the way they are customarily done because others have found out that is the right way to do them. Put it on the positive side and you will sleep better at night.

Don

I really appreciate the advice and input from you all. It gives me a lot of food for thought, and a much better understanding of the wonderous ways of electricity..

Thanks, Bill

Originally Posted by Itoldyouso

Do-able and should I do-able are two different things. It is do-able to jump off a cliff, but......................................

Sometimes you just do things the way they are customarily done because others have found out that is the right way to do them. Put it on the positive side and you will sleep better at night.

Don

No one is jumping off any cliffs! The guy wants to control the flow of electricity. With a switch he can open or close the circuit. It won't matter if it's on the positive or the negative side. The electron flow won't care as long as the circuit is complete with good clean connections! Don't believe it? Go to any car and lift off the negative terminal. Of course we all know the car won't start, won't crank, it just does NOTHING! Just what this guy wants. And just cause that's not how you think it's "customarily done" doesn't mean it's unsafe or bad. You aren't the know all / end all in the automotive field! I remember the days of positive ground systems, still work on a few of them too. And we all sleep well at night too! Sorry if this seems short or ill tempered, you're response implies something less than desireable.

I left my pile of bricks outside so I can't throw them at anyone

My rule of thumb, as decreed by something I read a few years ago(plus my own idea for safety) - if it is a standard, non electronic car, either negative or positive will do fine. If it's a newer car or has lots of electronics, the best way to disconnect is via the positive side. I do the positive side regardless plus my car - it has a fair amount of electronics, i.e.full MSD ignition and all of my gauges. And yes, I do have a separate 50 amp maxi-fused 10awg line to an individually fused module for those items I don't want to shut off with the master switch which so far, it's the stereo(5 amps) and the trunk lift(10 amps) with the solenoid operated doors to eventually follow - (maybe).

Originally Posted by 34_40

No one is jumping off any cliffs! The guy wants to control the flow of electricity. With a switch he can open or close the circuit. It won't matter if it's on the positive or the negative side. The electron flow won't care as long as the circuit is complete with good clean connections! Don't believe it? Go to any car and lift off the negative terminal. Of course we all know the car won't start, won't crank, it just does NOTHING! Just what this guy wants. And just cause that's not how you think it's "customarily done" doesn't mean it's unsafe or bad. You aren't the know all / end all in the automotive field! I remember the days of positive ground systems, still work on a few of them too. And we all sleep well at night too! Sorry if this seems short or ill tempered, you're response implies something less than desireable.

Geesh, didn't you see the smiley faces? My point was that while you are doing something like this it takes no more effort or money to do it the RIGHT way. Would it work by interupting the negative side? Sure, but the problem is that you still have the entire positive side unprotected and the potential is there, albeit slim, that it could short out against something metal and cause a problem.

Where I work we have to operate under strict guidelines by the American Boat and Yacht Council (ABYC) they mandate how and where every component of a boat is placed and installed. Again, I realize this is a car, but the principles are the same........both have engines and batteries. The Council insists the switch be on the positive side, for the reason I mentioned above. I have never seen any disconnect switch installed on the negative side and have been in this industry for over 20 years.

Sorry you took offense for some reason to another opinion, but when we give advice on any forum we need to present the best way to do things, not just one that would get by, and if I had to chose between you getting irked and him having an electrical fire, guess which one wins out?

Don