Why were so many British cars positive earth?

Pete C. wrote:
> "John S." wrote:
> >
> > When trying to figure out which wire is hot don't assume that anything
> > other than red color is not hot. It's a good way to get burned.
>
> Wrong - Do not assume anything at all. Test everything when there is any
> question as to how things have been wired. In the US at least, red is
> very often a hot lead for a 240v circuit.

Without trying to get into an argument here, that was what I said.

The original post said: My comment was just that it's "backwards"
from cars and regular electronics - black is ground unless it's house
wiring.

I said in response to not assume that any color other than red is not
hot.
In otherwords everything is potentially hot. Or in yet other words,
when you don't know the building or car, test everything.

>
> Pete C.

"N8N" > wrote in message
ups.com...
>
>
> Chas Hurst wrote:
> > "Pete C." > wrote in message
> > ...
> > > AZ Nomad wrote:
> > >
> > > Incorrect. Red is most certainly a "hot" lead in house wiring. For
240v
> > > circuits such as stoves, dryers, large A/C, etc. you have both black
and
> > > red hot leads along with your ground and if needed a neutral.
> > >
> > > Also as someone else has noted, white wires can also be hot leads if
the
> > > ends are marked with black or red tape.
> > >
> > > Pete C.
> >
> > I've never seen this. A 240V circuit uses the same (color) wire as a
120V
> > circuit. And a neutral is not needed or wanted.
>
> Sure it is, without a neutral you have no way of using one leg for a
> 120V circuit for, say, the light inside your dryer, or the timer motor
> for same...
>
> nate

You're right, I hadn't considered appliances.

"Paul Hovnanian" > wrote in message
...

>
> Its a British car. Which way does the smoke travel?

So you have read the smoke theory of electricity too! Dont remember where I
saw it,
but it relates, in an unusual way.

John S. wrote:
>
> Pete C. wrote:
>
>>"John S." wrote:
>>
>>>When trying to figure out which wire is hot don't assume that anything
>>>other than red color is not hot. It's a good way to get burned.
>>
>>Wrong - Do not assume anything at all. Test everything when there is any
>>question as to how things have been wired. In the US at least, red is
>>very often a hot lead for a 240v circuit.
>
>
> Without trying to get into an argument here, that was what I said.
>
> The original post said: My comment was just that it's "backwards"
> from cars and regular electronics - black is ground unless it's house
> wiring.
>
> I said in response to not assume that any color other than red is not
> hot.
> In otherwords everything is potentially hot. Or in yet other words,
> when you don't know the building or car, test everything.
>
>
>>Pete C.
>
>
True, especially when you come across used cars that have all sorts of
"unique" wiring... I've been guilty of using "what I had" instead of the
right color...

But any proper house wiring the black is hot and in most cars and
electronics the "standard" for black is ground.

(btw, this is Canada and the US only....)

name the 1s you know

59-66 Sunbeam Alpine Series I-IV
Bugeye Sprite

Erich

"TE Cheah" > wrote in message ...
> name the 1s you know
>
>

TE Cheah wrote:

> name the 1s you know


Most of them up to about 1960-'65. Many British cars with generators
(dynamos) were positive earth. Even today, there are requests from
classic owners on how to repolarise their dynamos to negative earth so
as to be able to use modern radios and tachometers and such.

As well, some owners want to be able to use their classics daily, in
regular traffic. This usually means the need to convert the car to have
negative earth and an alternator rather than a dynamo, necessitating
the replacement of things like dashboard instruments.

I gather (from the posts that were more-or-less on-topic) that the
reason British cars were positive earth was the same reason American
cars were positive earth: Convention and contemporary understanding of
DC current. But only up to about 1950.

Why they changed from positive to negative is alleged to have been 1) a
change in the way DC current was understood, and 2) corrosion.

I came across something interesting just today, however.
<http://www3.usenetarchive.org/File.asp?service=24603>
According to this reference, it had to do with...transistorised
accessories. You know, to me this makes more sense than any other
explanation I've yet come across.

On Mon, 27 Jun 2005, Hugo Schmeisser wrote:

> Why they changed from positive to negative is alleged to have been 1) a
> change in the way DC current was understood, and 2) corrosion.

Yep. If there's one thing british "car" "engineers" were good at, it was
finding ever more efficient ways of making a car rust.

On 2005-06-28 said:
>Newsgroups: rec.autos.tech
>59-66 Sunbeam Alpine Series I-IV
>Bugeye Sprite
>Erich
>"TE Cheah" > wrote in message .
>>net.my... name the 1s you know
'52 MG TD MkII (in my garage)
My recollection is that Chryslers in the '50's were positive ground too.


Tom Willmon
near Mountainair, (mid) New Mexico, USA

Net-Tamer V 1.12.0 - Registered

"Daniel J. Stern" > wrote in message
> Yep. If there's one thing british "car" "engineers" were good at, it was
> finding ever more efficient ways of making a car rust.

They are good, but can't beat the Italians, Daniel.