History of color coding?
- Thread starter rick5280
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Re: History of color coding?
Rick, sorry cannot help with when black and white were used for AC circuits.
But you are mistaken about your DC colors. There is no color code for DC. Each industry does there own thing. Walk into any telephone office and it will vary from office to office. The positive is black because it is the grounded conductor, just the oppisite of ac. The negative, or hot, can be black, white, blue, or red. It's just to confuse the Russian's.
Rick, sorry cannot help with when black and white were used for AC circuits.
But you are mistaken about your DC colors. There is no color code for DC. Each industry does there own thing. Walk into any telephone office and it will vary from office to office. The positive is black because it is the grounded conductor, just the oppisite of ac. The negative, or hot, can be black, white, blue, or red. It's just to confuse the Russian's.
bphgravity
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Re: History of color coding?
No basis of fact in my theory, but I do know that the first insulation covering used by Edison was a natural rubber-type that through processing became very black. This was used for both his DC series and parallel systems until the early 1920's. When AC took over and a grounded conductor was needed, white was the ideal choice to completely distinguish it from the black or "hot" conductor. This became popular enough to make it a standard. Also, Navy ships used a white flag to indicate a "neutral" vessal during world war one. (maybe there is a connection?) When the grounding conductor came into play, the obvious choice was green to indicate "Earth". This could all be crap, however you have inspired me to research this history. thanks.
No basis of fact in my theory, but I do know that the first insulation covering used by Edison was a natural rubber-type that through processing became very black. This was used for both his DC series and parallel systems until the early 1920's. When AC took over and a grounded conductor was needed, white was the ideal choice to completely distinguish it from the black or "hot" conductor. This became popular enough to make it a standard. Also, Navy ships used a white flag to indicate a "neutral" vessal during world war one. (maybe there is a connection?) When the grounding conductor came into play, the obvious choice was green to indicate "Earth". This could all be crap, however you have inspired me to research this history. thanks.
Re: History of color coding?
Sorry if I kick up an old post or two. I just found the forum today and am doing some reading.
bphgravity,
Did you ever come up with anything to support your theory. I thought the black, white and green explanations to be good theories.
Sorry if I kick up an old post or two. I just found the forum today and am doing some reading.
bphgravity,
Did you ever come up with anything to support your theory. I thought the black, white and green explanations to be good theories.
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