Wiring to negative ground

maylar said:

Any discussion of ground polarity will include the subject of galvanic corrosion. Most studies of that conclude that positive earth is better in that regard. The Brits and the Germans chose positive ground for that reason. The idiot Americans (GM) chose negative earth. And when alternators replaced generators (in the 60's?) GM was the driving force behind the change and negative earth became the de facto standard. Such is written on the internet, and we all know the web never lies

I switched to negative earth more than 10 years ago so I could use standard automotive LEDs. That was before the were polarity independent.

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And when those discussions were written, like when I was in school "current" was electrons flowing but today it's more magical. Galvanic corrosion and all forms of electroplating and un-electroplating (that I know of), are polarity dependent but there is a negative for every positive so which corrosion are you stopping?

Ford Model T Negative, Model A Positive and continued Positive until 1956 when back to Negative (Internet Info). My 55 Mercury was Positive.

If I remember right the 6-volt GM cars were Positive and they went to Negative when they went to 12-volt in the early fifties. But, GM was a lot looser group of individual manufacturers back then - they may not have all changed at the same time.

baz said:

Just this morning!
But that's not for here!!!!

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I seem to remember Vaseline being recommended???

cash said:

I was told it was to reduce corrosion?

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Nope.

maylar said:

Any discussion of ground polarity will include the subject of galvanic corrosion. Most studies of that conclude that positive earth is better in that regard. The Brits and the Germans chose positive ground for that reason. The idiot Americans (GM) chose negative earth. And when alternators replaced generators (in the 60's?) GM was the driving force behind the change and negative earth became the de facto standard. Such is written on the internet, and we all know the web never lies

I switched to negative earth more than 10 years ago so I could use standard automotive LEDs. That was before the were polarity independent.

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Idiots?
That's a pretty broad net.

Mike40M said:

Read somewhere that the difference is the direction of electrons in the spark plugs. Said to affects spark intencity.Those of us that has magneto ignition don't care. With waisted spark dual coil ignitions one spark plug has PE and the other NE. Never heard anybody complain of that. Earlier Nortons had negative earth up to ( I believe) early fifties.

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In aircraft flat engines which have an even number of cylinders the spark for an individual plug will always be the same polarity. That shows up on the spark plugs as on one polarity the wear will be on the side electrodes and the other the center, so spark plug position is rotated at each inspection/cleaning to even the wear. A single row radial (round) engine has an odd number of cylinders so the polarity from the magneto, which has an even number of poles, changes with every power stroke, so the wear is even.

Observing the sparks on a magneto test stand there's no discernible difference in the intensity of the sparks, at least to my eyes.

EstuaryBoy said:

Me too (galvanic??) but nothing out there now supports that...

(When did you last suffer a furry terminal??)

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When I started using AGM'a exclusively.

Alan L said:

Hi,
I suspect your physic teacher was engaging in some kind of magician’s slight of hand.
As a dummy I would say that if the actual electrons, that have arbitrarily been given a value of ‘negative’ some centuries ago and this has become the convention, and it scientifically provable that electrons move along a wire (for example) at I believe around several meters per second in the direction we ascribe as positive, then, by definition, we can say the current flows from negative to positive.
I suppose to delve a little deeper into the philosophy of it, if entropy tells us that all things move to equilibrium and we call an electron negative, it must by definition flow towards the positive

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Read again! All agree that current flow is from negative to positive OUTSIDE THE POWER SOURCE! Therefore, inside a battery, it is clearly from positive tot negative!

Physics is a lot deeper - it's has never been proven whether electron flow, hole flow, or something else is "current". What is clear is that new elements are not being made so atoms are not losing significate numbers of electrons and therefore electrons are not flowing in a traditional sense.

Lookup the word entropy - you've got it backwards.

Many brit cars, including the Mini, were positive Earth and rusted away in very little time. Hate to think how much faster that would've happened if negative Earthed ;-)

Then again, we had a negative earth Chevy Malibu in the '80s which rusted apart in about three or four years of hard winter driving in Ottawa. Dad always said it was b/c they were made from recycled metal, rust had a head start.

YING said:

I run a separate SAE plug that goes directly to the battery that is negative ground that runs to the handlebars that I can plug in GPS,phone,vest,etc.This is with a positive ground system.Works for me.
Mike

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Got to be careful with those SAE connectors. The exposed terminal will be negative and easy to have it touch the bike frame etc if not handling it with much attention. Ideally you should also change the fuse over the the other lead b/c it protects positive side of the device. This could cause device damage before fuse blows in a short situation.

In the late sixties, when I last had to deal with them, the military had long specified positive earth because of galvanic action. In theory at least, in automotive vehicle wiring, road and sea salt with water form an electrolyte and in a negative-earth system, the copper of wire terminals would be eroded from the terminal and deposited on the steel lamp socket ground screw or whatever. As there was a lot more of the vehicle frame, socket etc. than the copper terminal, it was preferable to have the metal deposited on the terminal and eroded from the frame.

Six-volt civilian GMC trucks were positive earth while six-volt Chevrolet trucks were negative earth. International trucks were positive earth, Studebaker trucks were positive, Dodge trucks were positive. Perhaps those makers who supplied a large portion of their production to the military found it inconvenient to have it both ways. Chevrolet had very large production runs so perhaps they could afford "military specials" that were positive earth. That doesn't explain why all Ford six-volt cars and trucks were positive earth though. Maybe they believed their wiring would last longer that way. Personally, I've found rust doesn't care and never sleeps.

marshg246 said:

Read again! All agree that current flow is from negative to positive OUTSIDE THE POWER SOURCE! Therefore, inside a battery, it is clearly from positive tot negative!

Physics is a lot deeper - it's has never been proven whether electron flow, hole flow, or something else is "current". What is clear is that new elements are not being made so atoms are not losing significate numbers of electrons and therefore electrons are not flowing in a traditional sense.

Lookup the word entropy - you've got it backwards.

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Hi Marsh,
your probably right but as electricity flows from an area of high charge to low charge I would assume that would be in keeping with the law of entropy. A battery discharges over time, it doesn’t gain charge, if you take my point. If it did that would be against entropy

maylar said:

Any discussion of ground polarity will include the subject of galvanic corrosion. Most studies of that conclude that positive earth is better in that regard. The Brits and the Germans chose positive ground for that reason. The idiot Americans (GM) chose negative earth. And when alternators replaced generators (in the 60's?) GM was the driving force behind the change and negative earth became the de facto standard. Such is written on the internet, and we all know the web never lies

I switched to negative earth more than 10 years ago so I could use standard automotive LEDs. That was before the were polarity independent.

Click to expand...

I read the same years ago. May have been this. Interesting fodder non the less.

EstuaryBoy said:

I seem to remember Vaseline being recommended???

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Oh Vicar....