Any colour wire can be Positive on many cars

True, but black is almost universally negative/ground.

Found on Rubbish Dumps

The other one was Fix or repair daily.

and FIAT: Fix It Again Tony

Tons Of Rust And No Acceleration.

I could go on...

Remember BMC cars with Positive ground? Why did they do this?? Very annoying when fitting many types of radios.

You could change the car's polarity with no side effects by reversing the battery and re-magnetising the generator field. Or better still fitting an alternator to replace the generator.

Remember Lucas car electrics? Lucas was known in auto electrical circles as the Prince of Darkness.

...but I avoided owning Fords all of my life so cannot say.

Me too. I've always owned cars with a Lion on the bonnet.

As for car earth wires, I am sure each would have its own colour codes, though I remember back to the days when we could build our own box trailers in the backyard and take them down to the motor registry to get them put on the books. The earth wire on a trailer or caravan should be white, with the coloured wires leading to tail, stop, left, right, brakes and auxiliary positives. If you end up putting on the 12 way plug instead of the 7 way plug you can also have your camp fridge, reverse lights and a few extra auxiliary circuits.

Remember BMC cars with Positive ground? Why did they do this??

IIRC, the claim was that it supposedly reduced rust triggered by electrolysis.

Lucas was known in auto electrical circles as the Prince of Darkness.

And it was known in British motorcycle owner circles as an acronym for "Leaves us cold and stranded'.

The other Automotive electrical wiring anomaly which always confounded me was that a 5pin trailer plug wiring is not compatible with a 7pin plug even though the 5pin plug can plug into the 7pin socket.
What genius thought of that.

Another one for Ford was "Fourth on race day" Holden "Hope our luck doesn't end now"

Looking back on it today ,The wiring was a walk in the park !!! no central locking nightmares !! we all had Fit healthy arms from winding windows up and down ! he he .BMC was very conventional and always slow to make changes, The Positive ground Generator was always the first modification to be made for customers who just bought the car.Generators were reliable enough but not practical if you got a flat battery.It took a hell of a long drive to charge the battery so an Altenator was the first modification. Lucus was always a nightmare and Bosch was much better, Apart from Generators there were other areas where BMC was stuck in the 40s, Synco on first gear was non-existent for years while others enjoyed a full synchro Gearbox ... It's just the British ways, They are conventionally old fashion in their designs. occasionally they stepped out of the square box of thinking and made a leap, The east-west engine we all enjoy today was really pushed and promoted with BMC. Then in 1966 when the Coopers Won Bathurst people stopped in their tracks and took to Coopers and new ideas ... In some of the cars, we built at work when I worked there years ago a 1275 cooper motor in a sports car fiberglass body could do 130 mph running a 45mm Webber ...I have been in them at that speed and built them in my work years, so BMC did get some things  spot on .Funny how we change in life , Now I only drive a 20-year-old ute at about 70km on a trip ! and as for working or building cars again for a living,I would rather digest Glass .
Plus you get rusty when you don't use your skills anymore and you lose confidence so I could never go back to it .
pete

I remember doing a tour of a Bosch plant in Melbourne in about 1980.

One of the things that fascinated me was the fully automated manufacture of alternators. The most impressive idea I saw was how they made the stator laminations from a single narrow strip of silicon steel, notched and wound into a spiral.

Consider the reduction in wastage achieved by not punching rings out of sheet steel!

This idea came from a worker at the factory. Bosch actively encouraged staff-driven innovation, they told me. It worked for them.

I believe Bosch alternators are still the most rugged and reliable.

Could someone answer as to why the mains wiring in buildings is the old red and black while all our power cords are brown and blue?
Is it a European thing?

Bosch Alternators , Diodes were on the outside of the casing ,so that is another reason we liked them . If it was over charging etc you had access to it .

Yes blame the Europeans. Power cords used to be red, black and green.

Reason building wire colours have stayed is to do with wiring regulations, that also have to allow for 3 phase circuits.

The colours for flexible cords changed so that colourblind people could get the wiring correct. Red and black look the same to a colourblind person (or so I am told). I can't vouch for it because I can still see all colours.

Building wiring used to be red, yellow, blue, black and green for A, B, C, N and E respectively. This scheme has been illegal for a number of years. All cable in new installations cannot include the colours yellow or green as E now = green/yellow. The other colours are red, white, blue and black respectively.

In some cases in the US, black is active, red is switch wire and white is neutral. This used to be the colour scheme on American-made PE cells and everyone complained about it because when the PE cell was hooked up under our colour scheme, the PE cell went BANG!. Now, the same brand of PE cell comes out here with red as active, black as neutral and white as the switch wire, which is how it should have been in the first place.

Here's some scary news - I was once told that in Russia, red is earth.

Lance, I just treat them all as active because I don't have the knowledge.
I use one hand and work with one wire .
People have done home wiring for years so anything can be going on there... People just do make shift repairs on appliances and houses...

Telecom practice used to be / maybe still is to use a red wire as a local ground on MDFs. Reason: sparkies won't cut into it and join other things to it.

You can see some good reasons for this.

On older wirewound MDFs in blocks of flats I do remember red earths being used.

These days it is green/yellow though.

Brad
I'm colour blind , red and black don't look alike. However dark brown and dark green are very hard to tell. Hence the earth wire has a yellow stripe. A few months ago I was wiring up a chassis and discovered I had the brown running to earth. This was in a cable that had no yellow stripe in the earth wire. Its a good thing I always double check my wiring.
I do find however the dyes that are of high Quality I have no problems with.
I remember one day having this conversation with one of my taxi customers . She said so how do you know when the stop lights on ( yes she was blonde lol).