Newbie Q's, break ground instead of positive?

[Roxengard]

Maybe some really dumb questions but I'm electrically challenged and I'm trying to wire a car from scratch for the first time.

Can you use the battery disconnect switch to break the negative from the battery instead of the positive?
If so, how will that stop the one-wire alternator from running the system, I guess the alt. will act as its own ground?

Reason I'm asking is that I feel that it would be alot easier to wire the car that way. Maybe the ground has to be isolated completely from the chassie and not just the battery?
If that is the case, I might as well wire the disconnect to the positive.
Btw, I know NHRA requires that the positive side be broken...

Kevlar pants are on, light up your throwers and flame away :-D

[rock]

IHRA also states that it must be on the positive side

[LTLHOMER]

Maybe some really dumb questions but I'm electrically challenged and I'm trying to wire a car from scratch for the first time.

Can you use the battery disconnect switch to break the negative from the battery instead of the positive?
If so, how will that stop the one-wire alternator from running the system, I guess the alt. will act as its own ground?

Reason I'm asking is that I feel that it would be alot easier to wire the car that way. Maybe the ground has to be isolated completely from the chassie and not just the battery?
If that is the case, I might as well wire the disconnect to the positive.
Btw, I know NHRA requires that the positive side be broken...

Kevlar pants are on, light up your throwers and flame away :-D

They mandate breaking the positive because if you have a frayed ground or something, and the thing is always getting power, you will get a short. But if you have frayed ground, and the cutoff is to the power, you will not get a short until the switch is on and in case of a fire, that can be shutoff easily.

Basically it's safer to break the positive because without the positive, it doesn't matter if the component finds an alternate ground.

[Roxengard]

Thanks for the replys, I thought that there was a good reason not to do it, just never knew why.

[Ed Kurzawa]

do not want to step on anbody's toes . this is my son's web spot on the bullet site ,i used to do a lot of electricle work on a major municipal police fleet .any time you break a ground under power you run a high risk of that broken ground momentarily seeking the path of least resistance.a positive wire with little to no measureable restance.basically anything including ignition boxes ,taches,digital controls ect. example,oldschool mechanics disconnect negative cable from battery while engine is running to see if alt. is charging.on modern vehicles w computers,digital dashes and digital funtions ,it will blow somthing out. work with thes guys every day. electricity is like a water leak, it will follow the path of least resistance 9 out of10 times.hope this makes it easier for you next time.ground problems are one of the leading causes of component failure.not trying to step on anybody elses posts. just wanted to make it general to anybody who don't work with elect. just tried to make it simple as i could.Ed Kurzawa SR.

[Monty Mikho]

Dang we got Pappa Ed posting.. Welcome :)

[Ed Kurzawa]

Now that he figured out how to post, hell be a post whore, watch......(sorry i just hi-jacked a tech thread...)