Re: [DML] why denote "negative ground" on stickers

[mike clemens <rmclemns@xxxxxxxxx>]

David,  I'm not sure of your age, but many years ago
cars were made (especially from Europe and MG comes to
mind) that the positive cable was connected to the
frame of the vehicle.  Theory was, that since the
vehicle was insulated by the tires, if the whole car
was connected to the positive side, then you could
attach any accessories you wanted, as long as you tied
them into the negative terminal that was attached to a
cable that ran the length of the car.

This was actually a very forward thinking idea, except
for one MINOR error.  If you were ever in an accident
and the body was grounded to the object you touched,
(metal light poles, guard rails, etc), then the
current flow from from the battery positive side would
use the path of least resistance, and would continue
to work until the battery was disconnected.  Example: 
you have a fender bender with a guard rail.  Your car
is still touching the guard rail and a small fuel leak
develops from the impact.  Your battery is still
connected to the car and the tow truck comes to pull
away your car.  As soon as they pull the car away from
the metal rail, a spark is produced and Wallah, you
have the makings of a nice little fire that is fed by
gasoline.

Second reason, when the US of A became the car capitol
of the world (volume wise), all other world
manufacturers wanted to sell to us and they had no
choice but to make their vehicles comply with US
standards at the time.  Since Henry Ford was tied to
Thomas Edison, he used a DC system in his cars that
Edison promoted---negative ground.  John D wanted to
sell his car in the US, so the placards were put there
to assure buyers that 'his European car' met the US
standards.  Hence, negative ground placards.

Lastly, if you are ever at an antique car show, and
the owner of an MGA needs a 'jump' to start their 
car, make sure you disconnect your battery from your
system before you connect the jumper cables.  They use
two six volt batteries in series, positive ground, and
if you make a mistake, their amperage will fry the
system in your Delorean.

Mike   TPS   1630


--- daviddlasvegas <daviddlasvegas@xxxxxxxxx> wrote:

> Why do the warning stickers on the car say "this car
> is negative 
> ground". On a DC electrical system ground has to be
> negative doesn't 
> it? How could you have a 'positive ground' that
> doesn't make any sense.
> 
> 



 
____________________________________________________________________________________
Don't get soaked.  Take a quick peak at the forecast
with the Yahoo! Search weather shortcut.
http://tools.search.yahoo.com/shortcuts/#loc_weather


To address comments privately to the moderating team, please address:
moderators@xxxxxxxxxxx

For more info on the list, tech articles, cars for sale see www.dmcnews.com

To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews 
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/dmcnews/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/dmcnews/join
    (Yahoo! ID required)

<*> To change settings via email:
    mailto:dmcnews-digest@xxxxxxxxxxxxxxx 
    mailto:dmcnews-fullfeatured@xxxxxxxxxxxxxxx

<*> To unsubscribe from this group, send an email to:
    dmcnews-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/