Positive ground or Negative ground

"Sharon K.Cooke" > wrote in message
...
>
>
> K`Tetch wrote:
> >
> > On Fri, 25 Feb 2005 09:34:04 -0600, "Sharon K.Cooke"
>
> > wrote:
> >
> > >Not sure about high-powered DC current, but I do know what happens
in
> > >the real world for 12VDC. BTW, I do have an engineering degree, and
have
> > >had several courses in electrical/electronics theory. Also, if it
counts
> > >for "creds", I moonlighted repairing TV sets while I was going to
> > >school.
> >
> > Well then, you should be able to tell us why 'negative side
switches'
> > last longer than, so, please, enlighten us.
> >
>
> Stating it as simply as possible, when a device is powered via ground
> switching, the device acts a capacitor to minimize surge & 'bounce'.
If
> you don't believe that a grounding switch lasts longer than a switch
> used to turn on a positive current thru the switch and then to the
> device, please let me know when & where you'll be changing your nest
car
> battery; I'd like to watch, Hell, I could probably sell tickets if you
> promise to remove the positive terminal on the old battery first, and
> also promise to connect the ground teminal on the new battery before
you
> connect the positive terminal.
>

No problem. I do it that way on the Blazer all the time. Pos terminal is
easier to get to than Neg. There is a reason to remove the ground first
BUT it isn't anything to do with what you claim. It is because ALL the
metal around the battery will be at ground potential. So by removing the
ground first you eliminate the possibility of a short IF you hit
something with the metal wrench. That is the ONLY reason why it is done.
NOTHING ELSE.

As for ground switching being better WRONG. 10 amps is 10 amps,
regardless of which side your breaking, as for the powered item being a
capacitive load it would be on either side. Doesn't matter which side
you break. Just a fact.




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On Fri, 25 Feb 2005 14:59:50 -0600, "Sharon K.Cooke" >
wrote:

>
>
>K`Tetch wrote:
>>
>> On Fri, 25 Feb 2005 09:34:04 -0600, "Sharon K.Cooke" >
>> wrote:
>>
>> >Not sure about high-powered DC current, but I do know what happens in
>> >the real world for 12VDC. BTW, I do have an engineering degree, and have
>> >had several courses in electrical/electronics theory. Also, if it counts
>> >for "creds", I moonlighted repairing TV sets while I was going to
>> >school.
>>
>> Well then, you should be able to tell us why 'negative side switches'
>> last longer than, so, please, enlighten us.
>>
>
>Stating it as simply as possible, when a device is powered via ground
>switching, the device acts a capacitor to minimize surge & 'bounce'. If
>you don't believe that a grounding switch lasts longer than a switch
>used to turn on a positive current thru the switch and then to the
>device, please let me know when & where you'll be changing your nest car
>battery; I'd like to watch, Hell, I could probably sell tickets if you
>promise to remove the positive terminal on the old battery first, and
>also promise to connect the ground teminal on the new battery before you
>connect the positive terminal.

You know, i did some looking, and i can find NOTHINg to support your
assertation. On the other hand, there is something which disproves it,
and its a little something called "KIRCHOFF'S CURRENT LAW" Basically
it says the current into a point is equal to the current out. So, the
curent into the switch is the same as the current cmming out. the same
for the device, so no matter where the switch is, there will always be
surge.

I've disconnected terminals on batteries in all 3 types of order,
positive terminal first, negative first, and both together 9easy to do
whe you got a linked pair of anderson powerpoles to pull) Made no
difference that i could tell. The reason you disconnect the
negative/grond first on a battery is because typically, you use metal
tools. if you Disconnect the positive first, its possible that you
could actidentally make a short, via the tool, between the negatively
connected odywork/engine, and the positively connected tool. This is
why, also, for the same reason, on positively grounded cars, you're
told to disconnect the +ve terminal first.

Anyway, based on what you said above, please enlighten me as to what
degree, and from where, so i can be sure to avoid graduates from there
when doing the job applications. Not being able to perform a simple
nodal analysis would be BAD for any employee of mine.

K`Tetch wrote:
>
> On Fri, 25 Feb 2005 14:59:50 -0600, "Sharon K.Cooke" >
> wrote:
>
> >
> >
> >K`Tetch wrote:
> >>
> >> On Fri, 25 Feb 2005 09:34:04 -0600, "Sharon K.Cooke" >
> >> wrote:
> >>
> >> >Not sure about high-powered DC current, but I do know what happens in
> >> >the real world for 12VDC. BTW, I do have an engineering degree, and have
> >> >had several courses in electrical/electronics theory. Also, if it counts
> >> >for "creds", I moonlighted repairing TV sets while I was going to
> >> >school.
> >>
> >> Well then, you should be able to tell us why 'negative side switches'
> >> last longer than, so, please, enlighten us.
> >>
> >
> >Stating it as simply as possible, when a device is powered via ground
> >switching, the device acts a capacitor to minimize surge & 'bounce'. If
> >you don't believe that a grounding switch lasts longer than a switch
> >used to turn on a positive current thru the switch and then to the
> >device, please let me know when & where you'll be changing your nest car
> >battery; I'd like to watch, Hell, I could probably sell tickets if you
> >promise to remove the positive terminal on the old battery first, and
> >also promise to connect the ground teminal on the new battery before you
> >connect the positive terminal.
>
> You know, i did some looking, and i can find NOTHINg to support your
> assertation. On the other hand, there is something which disproves it,
> and its a little something called "KIRCHOFF'S CURRENT LAW" Basically
> it says the current into a point is equal to the current out. So, the
> curent into the switch is the same as the current cmming out. the same
> for the device, so no matter where the switch is, there will always be
> surge.
>
> I've disconnected terminals on batteries in all 3 types of order,
> positive terminal first, negative first, and both together 9easy to do
> whe you got a linked pair of anderson powerpoles to pull) Made no
> difference that i could tell. The reason you disconnect the
> negative/grond first on a battery is because typically, you use metal
> tools. if you Disconnect the positive first, its possible that you
> could actidentally make a short, via the tool, between the negatively
> connected odywork/engine, and the positively connected tool. This is
> why, also, for the same reason, on positively grounded cars, you're
> told to disconnect the +ve terminal first.
>
> Anyway, based on what you said above, please enlighten me as to what
> degree, and from where, so i can be sure to avoid graduates from there
> when doing the job applications. Not being able to perform a simple
> nodal analysis would be BAD for any employee of mine.

Good luck with your belief system. Mine could keep an outgassing battery
from exploding, or possibly keep a metal wrench from being welded to the
sheet metal. Yours ...

BTW, my degree field, and where I obtained it, is none of your business,
even if you actually have one (doubtful). "Flaming" people on the 'Net
does not count as a business.

"When you argue with a fool, the result is two fools arguing."

On Fri, 25 Feb 2005 18:14:49 -0600, Sharon K.Cooke wrote:

> Good luck with your belief system. Mine could keep an outgassing battery
> from exploding, or possibly keep a metal wrench from being welded to the
> sheet metal. Yours ...

I've been watching this thread with amusement, and must now say that you
are indeed wrong (on at least two counts).

First, the others are correct when they say that it makes NO difference
where you "break" a circuit, as the current is the same in either case.

Second, your wrench welding comment above is wrong, because if you touch
the wrench to the engine while it is connected to the positive terminal,
very bad things happen. This is because the engine is connected to the
negative terminal via the negative battery lead. If, however, you first
disconnect the negative lead, and then touch your wrench between the
positive lead and the engine, there is NO connection back to the negative
terminal, and NOTHING will happen. Can you understand that?

> BTW, my degree field, and where I obtained it, is none of your business,
> even if you actually have one (doubtful). "Flaming" people on the 'Net
> does not count as a business.

Indeed not. However, a degree in a field other than what we are currently
discussing does not count for anything, either.

> "When you argue with a fool, the result is two fools arguing."

Now that is absolutely correct!

--
If you're not on the edge, you're taking up too much space.
Linux Registered User #327951

In > "Sharon K.Cooke" > writes:

[ lots snipped. make that everything snipped... ]

I'm afraid I just remember enough about this to be scary without being
useful, but...

When I was working with NYC's EMS folk, we were told by the mechanics that
the emergency lamps in the rear of the ambulances were ground switched.
This sounded pretty wierd but they explained it in a way that made sense
at the time.

I don't recall what they said about it, but I just confirmed with a
colleague of mine from back then that he remembers it also.

--
__________________________________________________ ___
Knowledge may be power, but communications is the key

[to foil spammers, my address has been double rot-13 encoded]

On Fri, 25 Feb 2005 08:36:49 -0600, "Sharon K.Cooke" >
wrote:

>Explain WHAT in a scientific manner? It's a given that if you use a
>switch to close a ground, it's easier on the switch and it (the switch)
>will last until it breaks simply from mechanical wear & tear. Going the
>other way, with a fixed ground and using an electrical path thru the
>switch to power the device will burn out the contacts on switches
>"before their time". I have replaced a number of MF & headlight switches
>(FoMoCo mostly) as proof of that. I have NEVER replaced one on a Toyota.
>
>Ground switching (of headlights, anyway) has been around for at least 30
>years - look at any Toyota or Datsun (Nissan, now) - and has zero to do
>with CANBUS, explained as; http://www.cetrek.co.uk/CanbusSet.html
>
>

I was service manager for a good sized Toyota dealer for 10 years,and
did most of the electrical troubleshooting as well, so I know Toyota
wiring. I also know that in a series circuit it matters not a whit
where you place the switch. The reason Toyota and Nissan swirches are
less likely to fail is twofold. Firstly, they tend to be of a higher
quality, and secondly, Toyota and Nissan tend to relay switch a lot
more than Ford

You show me, using sound electrical theory how ground switching is
superior to power switching...
>
wrote:
>>
>> On Thu, 24 Feb 2005 13:06:40 -0600, "Sharon K.Cooke" >
>> wrote:
>>
>> >Actually, Chrysler likes to do some electrical things the other way,
>> >with ground-switched tail lights. Even Ford has done ground-switched
>> >tail lights, and the Ford air suspension solenoid valves are all
>> >ground-switched. Ground-switching IS the superior way to handle DC
>> >switching (less wear & tear on switches), but costs a little more to
>> >implement, so the majority of automakers avoid it.
>> >
>>
>> I'd like you to explain THAT in a scientific manner.
>>
>> The only reason some things are ground switched is to simplify
>> electronic control.
>>
>> Interior lamps are often ground switched, because there are at leat 3
>> switches controlling the lamps, and grounding switches on the doors
>> are infinitely simpler than power switches in the door jams.
>>
>> Ground switching rewuires a lot more wiring in most other cases, as
>> power must be supplied (by wire) from the battery, and the ground must
>> be returned(by wire) to the switch.
>>
>> With the new can-bus systems, the actual switch can be at the back of
>> the car, connected only to the "power" wire which also carries the
>> networked control signal. In this case, ground switching may be used -
>> and may be the simplest.
>> >the fly wrote:
>> >>
>> >> On Thu, 24 Feb 2005 06:54:50 GMT, "2.3Sleeper"
>> >> > wrote:
>> >>
>> >> >92 Eagle Vision (Intrepid basically). Issues with the tail lights and a
>> >> >reverse warning light installation. Someone suggested that it might be a
>> >> >negative ground system which will effect the end result of what I was trying
>> >> >to achieve.
>> >> >
>> >> >Anyone have an answer on this one?
>> >> >
>> >> >Don Manning
>> >> >
>> >>
>> >> Virtually ALL vehicles built in North America since the
>> >> mid-1950s have negative-ground electrical systems.

On Fri, 25 Feb 2005 09:34:04 -0600, "Sharon K.Cooke" >
wrote:

>Not sure about high-powered DC current, but I do know what happens in
>the real world for 12VDC. BTW, I do have an engineering degree, and have
>had several courses in electrical/electronics theory. Also, if it counts
>for "creds", I moonlighted repairing TV sets while I was going to
>school.
>
Heaven help us all - an engineering degree and several courses in
electrical and electronis theory - that explains a lot.
>K`Tetch wrote:
>>
>> On Fri, 25 Feb 2005 08:36:49 -0600, "Sharon K.Cooke" >
>> wrote:
>>
>> >Explain WHAT in a scientific manner? It's a given that if you use a
>> >switch to close a ground, it's easier on the switch and it (the switch)
>> >will last until it breaks simply from mechanical wear & tear. Going the
>> >other way, with a fixed ground and using an electrical path thru the
>> >switch to power the device will burn out the contacts on switches
>> >"before their time". I have replaced a number of MF & headlight switches
>> >(FoMoCo mostly) as proof of that. I have NEVER replaced one on a Toyota.
>>
>> Obviously someone has never been in an electronics/electrical class
>>
>> You know what circuits are, i take it?
>>
>> I work a lot with high-power DC stuff (110V+, at sometimes 1200A) and
>> it doesn't matter where on the circuit a switch is, as, you see, a
>> circuit is a loop, and electron flow goes around ALL of the circuit
>> equally.
>>
>> Why, in your opinion are ground switches better? is it because the
>> electrons 'aren't as tired' as they've only just left the battery, and
>> so can make a cleaner spark at near contact, one which won't
>> deteriorate the contact, unlike if they were positive switched, where
>> they'd be exhausted and jump any old way, destroying contacts?
>>
>> >
>> >Ground switching (of headlights, anyway) has been around for at least 30
>> >years - look at any Toyota or Datsun (Nissan, now) - and has zero to do
>> >with CANBUS, explained as; http://www.cetrek.co.uk/CanbusSet.html
>> >
>> >
>> >
>> wrote:
>> >>
>> >> On Thu, 24 Feb 2005 13:06:40 -0600, "Sharon K.Cooke" >
>> >> wrote:
>> >>
>> >> >Actually, Chrysler likes to do some electrical things the other way,
>> >> >with ground-switched tail lights. Even Ford has done ground-switched
>> >> >tail lights, and the Ford air suspension solenoid valves are all
>> >> >ground-switched. Ground-switching IS the superior way to handle DC
>> >> >switching (less wear & tear on switches), but costs a little more to
>> >> >implement, so the majority of automakers avoid it.
>> >> >
>> >>
>> >> I'd like you to explain THAT in a scientific manner.
>> >>
>> >> The only reason some things are ground switched is to simplify
>> >> electronic control.
>> >>
>> >> Interior lamps are often ground switched, because there are at leat 3
>> >> switches controlling the lamps, and grounding switches on the doors
>> >> are infinitely simpler than power switches in the door jams.
>> >>
>> >> Ground switching rewuires a lot more wiring in most other cases, as
>> >> power must be supplied (by wire) from the battery, and the ground must
>> >> be returned(by wire) to the switch.
>> >>
>> >> With the new can-bus systems, the actual switch can be at the back of
>> >> the car, connected only to the "power" wire which also carries the
>> >> networked control signal. In this case, ground switching may be used -
>> >> and may be the simplest.
>> >> >the fly wrote:
>> >> >>
>> >> >> On Thu, 24 Feb 2005 06:54:50 GMT, "2.3Sleeper"
>> >> >> > wrote:
>> >> >>
>> >> >> >92 Eagle Vision (Intrepid basically). Issues with the tail lights and a
>> >> >> >reverse warning light installation. Someone suggested that it might be a
>> >> >> >negative ground system which will effect the end result of what I was trying
>> >> >> >to achieve.
>> >> >> >
>> >> >> >Anyone have an answer on this one?
>> >> >> >
>> >> >> >Don Manning
>> >> >> >
>> >> >>
>> >> >> Virtually ALL vehicles built in North America since the
>> >> >> mid-1950s have negative-ground electrical systems.

On Fri, 25 Feb 2005 14:59:50 -0600, "Sharon K.Cooke" >
wrote:

>
>
>K`Tetch wrote:
>>
>> On Fri, 25 Feb 2005 09:34:04 -0600, "Sharon K.Cooke" >
>> wrote:
>>
>> >Not sure about high-powered DC current, but I do know what happens in
>> >the real world for 12VDC. BTW, I do have an engineering degree, and have
>> >had several courses in electrical/electronics theory. Also, if it counts
>> >for "creds", I moonlighted repairing TV sets while I was going to
>> >school.
>>
>> Well then, you should be able to tell us why 'negative side switches'
>> last longer than, so, please, enlighten us.
>>
>
>Stating it as simply as possible, when a device is powered via ground
>switching, the device acts a capacitor to minimize surge & 'bounce'. If
>you don't believe that a grounding switch lasts longer than a switch
>used to turn on a positive current thru the switch and then to the
>device, please let me know when & where you'll be changing your nest car
>battery; I'd like to watch, Hell, I could probably sell tickets if you
>promise to remove the positive terminal on the old battery first, and
>also promise to connect the ground teminal on the new battery before you
>connect the positive terminal.

Sharon - I taught auto mechanics for a few years.
There is NO REASON to remove the NEGATIVE terminal first.
The important thing is to remove the GROUNDED TERMINAL FIRST.
The reason for this is:
If your wrench inadvertently touches "ground" while removing the
"grounded" terminal you do not draw a spark, burn the wrench, or blow
up the battery because no current flows through the wrench.
If you remove the ungrounded terminal first, and inadvertently touch
ground, one or more of the aforementioned will happen - often with
spectacular results.

If the ground is removed first, and THEN while removong the ungrounded
terminal, the wrench touches ground, NOTHIN HAPPENS because no circuit
is completed.

That, my dear, is the long and the short of it.

On Sat, 26 Feb 2005 01:02:52 +0000 (UTC), danny burstein
> wrote:

>In > "Sharon K.Cooke" > writes:
>
>[ lots snipped. make that everything snipped... ]
>
>I'm afraid I just remember enough about this to be scary without being
>useful, but...
>
>When I was working with NYC's EMS folk, we were told by the mechanics that
>the emergency lamps in the rear of the ambulances were ground switched.
>This sounded pretty wierd but they explained it in a way that made sense
>at the time.
>
>I don't recall what they said about it, but I just confirmed with a
>colleague of mine from back then that he remembers it also.


VERY simpl;e explanation why things like emergency lights are often
ground switched.
The power is applied to one side of the lamp, directly, through a fuse
or breaker. (sometimes also through an "isolating" or "lockout" switch
to prevent them from being turned on when they should not be - like
when the vehicle is parked) Then the other side of the lamp is
grounded through a locally mounted switch. IF something goes wrong
with the switch, and it should happen to short to ground (corrosion
due to moisture in an axternally mounted lamp assembly is one common
occurence)all that happens is the light comes on. If POWER switched,
this would cause a dead short, hopefully blowing the fuse, but also
possibly overheating and burning the wire.
Interior and cabin lamps are also connected this way, because a remote
grounding switch can be easily connected to turn the light on from a
"priority" location.

On Fri, 25 Feb 2005 18:14:49 -0600, "Sharon K.Cooke" >
wrote:

>
>
>K`Tetch wrote:
>>
>> On Fri, 25 Feb 2005 14:59:50 -0600, "Sharon K.Cooke" >
>> wrote:
>>
>> >
>> >
>> >K`Tetch wrote:
>> >>
>> >> On Fri, 25 Feb 2005 09:34:04 -0600, "Sharon K.Cooke" >
>> >> wrote:
>> >>
>> >> >Not sure about high-powered DC current, but I do know what happens in
>> >> >the real world for 12VDC. BTW, I do have an engineering degree, and have
>> >> >had several courses in electrical/electronics theory. Also, if it counts
>> >> >for "creds", I moonlighted repairing TV sets while I was going to
>> >> >school.
>> >>
>> >> Well then, you should be able to tell us why 'negative side switches'
>> >> last longer than, so, please, enlighten us.
>> >>
>> >
>> >Stating it as simply as possible, when a device is powered via ground
>> >switching, the device acts a capacitor to minimize surge & 'bounce'. If
>> >you don't believe that a grounding switch lasts longer than a switch
>> >used to turn on a positive current thru the switch and then to the
>> >device, please let me know when & where you'll be changing your nest car
>> >battery; I'd like to watch, Hell, I could probably sell tickets if you
>> >promise to remove the positive terminal on the old battery first, and
>> >also promise to connect the ground teminal on the new battery before you
>> >connect the positive terminal.
>>
>> You know, i did some looking, and i can find NOTHINg to support your
>> assertation. On the other hand, there is something which disproves it,
>> and its a little something called "KIRCHOFF'S CURRENT LAW" Basically
>> it says the current into a point is equal to the current out. So, the
>> curent into the switch is the same as the current cmming out. the same
>> for the device, so no matter where the switch is, there will always be
>> surge.
>>
>> I've disconnected terminals on batteries in all 3 types of order,
>> positive terminal first, negative first, and both together 9easy to do
>> whe you got a linked pair of anderson powerpoles to pull) Made no
>> difference that i could tell. The reason you disconnect the
>> negative/grond first on a battery is because typically, you use metal
>> tools. if you Disconnect the positive first, its possible that you
>> could actidentally make a short, via the tool, between the negatively
>> connected odywork/engine, and the positively connected tool. This is
>> why, also, for the same reason, on positively grounded cars, you're
>> told to disconnect the +ve terminal first.
>>
>> Anyway, based on what you said above, please enlighten me as to what
>> degree, and from where, so i can be sure to avoid graduates from there
>> when doing the job applications. Not being able to perform a simple
>> nodal analysis would be BAD for any employee of mine.
>
>Good luck with your belief system. Mine could keep an outgassing battery
>from exploding, or possibly keep a metal wrench from being welded to the
>sheet metal. Yours ...

Been there, done that, got the TV, and nationally shown footage of it
(batteries shorting, and catching fire - they rarely explode, even
fuly sealed batteries swell, then outgass, and te hydrogen ignites.
Thank god for me old muckas at firetrace, half the time they put the
fire out before i can get close with the co2.)

>
>BTW, my degree field, and where I obtained it, is none of your business,
>even if you actually have one (doubtful). "Flaming" people on the 'Net
>does not count as a business.

Yes, i ahve one, although i got it in europe (where the entire time is
spent on the actual subject of the degree). Its a very nice robotics
degree, and is roughly equivilent to a US masters degree.

>
>"When you argue with a fool, the result is two fools arguing."
Aye, if only we were arguing, as opposed to me stating widely known
fact, and you thinking you're in la-la-land.