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| Subject - insulation colors | |
| paul.landino |
Please help with a question I have on a quiz for school. I believe they are asking about the ungrounded conductor, as I know the NEC has requirements for the grounding and grounded or neutral conductors. Also I think the answer for 120/240-volt is "a" Supply the most common insulation colors for the circuits described below: a. black, blue, white b. black, blue, red, white c. brown, orange, yellow, gray _120/240-volt, single-phase, three-wire _120/208-volt, three-phase, four-wire _277/480-volt, three-phase, four-wire Also if anyone knows where I can find this information in the NEC, I would greatly appreciate it. I'm new to this site and I hope I'm posting this in the right place. Thanks. Paul |
| David Hyatt | I would say black red and whiye would be more common foe single phase 240. The others look ok. |
| JimmyDee | First of all I would like to welcome you to the Electrical Knowledge site. I think the answers are in order A, B, & c but not sure. I have been told there are some industry standards for hot (ungrounded) wire colors but the NEC only address that the neutrals be white or gray, ground if insulated be green or uninsulated be bare, and all ungrounded can be any other color but green or white/gray. An exception is the wild leg which has to be orange if in the presence of the neutral. (Used to be red when I was much younger). The NEC does require color coding for isolated circuits dependant on circuit number and heater leads depending on voltage. Sorry I don't know the other color usage you are talking about because I never had to know it for any reason. Not sure why anyone would go to the trouble of teaching it now. Maybe someone can enlighten me. Jim |
| JimmyDee | Just did a search and here is a response a while back from "Iwire". Keep in mind that this is not NEC but only what one region does. I'm not saying it is good or bad, only that the NEC doesn't require it.quote: Jim |
| iwire | quote: Hi Paul you can not find this info in the NEC as it is not there. I really think the question itself is a poor one. Unless there are local ordnances there is no official color code for ungrounded conductors. As Jimmy posted, in this area Brown, Orange, Yellow and Gray is common for 480/277. Black, Red, Blue white for 208/120 We do not use white, black and blue for 240/120. We would use white, black and red for that. After all that is how the cables come.  3 wire cable is white, black, red. 4 wire cable is white, black, red, blue. Let me say this, when you do get out in the feild NEVER decide the voltage of the circuit based on the color of the wire. Get out a meter and measure the voltage. 120 volt equipment has a very short life span if mistakenly connected to a 277 volt supply. 
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| JimmyDee | quote: Great advice except I'll go one further. Never assume the voltage of any wire, period. Always check. Rule #2, always check. Rule #3, always check. There are no old careless electricians. I remember one time I was about to take the fuses out of a 480 volt disconnect and thought, I better check them. The guy that bumped off the assembly line into the electrical department fed the disconnect from the bottom and the fuses were hot. I'll repeat the rules once again: Rule #1, always check. Rule #2, always check. Rule #3, always check. When an electrician assumes, they usually die young. Jim |
| paul.landino | Thank you for the help, and thank you Jim for welcoming me to the site (very informative). I'm sure I'll be back often. Thanks again. Paul |
| lctrc789 | Paul, the wire colors I think you are referring to is not code but a general rule of thumb used in the field. The NEC states that white can be used for grounded conductors (gray used to be used but was deleted in 2003) Bare wires or green for grounding conductors. The colors many contractors use are: BLACK - BLUE - WHITE 120/240 single phase BLACK -RED -BLUE-WHITE 120/208 3 phase BROWN - ORANGE -YELLOW - GRAY 277/480 3 phase They are right the color orange is used in high leg delta services by the NEC. Again always check the voltage present and never assume by color alone, many contractors use these as a general guideline but not always, good luck to you. |
| iwire | Pat we can still use "Gray" the words "Natual Gray" where removed. From the 2002 NEC quote: |