Ok never posted here before. Been lurking for years on this site. Lot of good advice. So here is my question. Recently worked on troubleshooting some lights at a postal facility. Noticed in the conduit over head green wires that were HOT! Ended up I had to open up the panel and behold the 480/277 panel had black, blue, red, and GREEN wires on the breakers. This building was dedicated in 1959 under President Eisenhower. So my question is was it ok under the NEC to use green wires on breakers in 1958-59? This may be a fun one to research. By the way in another post office I saw a lot of Federal Pacific equipment. Need to get pictures.
Just another reason not to trust conductor colors, always verify.
This was taken years ago, if you look on the right hand row of breakers with the Crouse-Hinds breakers in the ITE panel, this was long before Siemens bought Murray, it's hard to make out the green conductor connected to one of the breakers.
Circa 1968 Zinsco bolt on panel green being used to supply 208V 3Ø to a now removed bedpan sterilizer, wiring gone too.
I don't think 'green' became a color reserved for the ground wire until sometime around 1955. Heck, 3-prong receptacles were more the exception than the rule, well into the 60's.
I've encountered several knob & tube installations where green was 'hot' and the neutral was black.
I've also seen buildings from the late 60's where the blue wires aged to appear more green than anything else.
It's also worth remembering that the practice of "always" including a green wire in our conduit is fairly recent. I don't think I came across that attitude until the 90's, and even then it seemed to be confined to California-trained guys. Even today, we can often use the conduit alone as the ground, at least according to the rule book.
In some European countries there were no official wire colours until the harmonisation in the 60s! In Sweden earth was red but live and neutral could be almost anything (most commonly black and white but which one was live depended on local customs), Italy didn't have ANY standards and neither did Austria until 1938. Really old flex from the 1930s and earlier usually has only two grey wires and I've seen 4-wire with two greys and two blacks more than once. Fixed wiring back then was usually black, black and in case another colour was required for 2-way circuits etc. black was introduced. Troubleshooting gets REALLY interesting in those old installations! Not to mention the fact that they didn't necessarily use conduit back then but occasionally ran wires directly in plaster, even omitting junction boxes. I've worked in a house (built 1913) where they nailed two wires to the lath before the ceiling was plastered, running along a wall, and just tapped off that "trunk" straight above any light switch or socket.