QuestionWhat was the advantage of positive
ground vs negative ground?
AnswerGreat question with a simple answer, partly historic.
Oftentimes, stationary electrical equipment (turbines, generators, transformers), especially those mounted to steel structures set into concrete into the ground, used positive ground. Apparently a small amount of current "leak" was designed in to discourage corrosion in the structural members.
Somehow (cross-pollination of engineering knowledge?), Fords used positive ground in their cars (with the exception of the Model T's with electric start from 1919 until 1927), by insistence of Henry Ford, who apparently had a bridge engineer as an advisor...
Fords didn't go to negative ground until '56. GM was negative ground right from the beginning; Brit cars were mostly positive until RR and Bentley began using GM parts in their cars, then they went negative while most of the rest remained positive.
These days, it's entirely convenience and standardization.
--Paul
