White vs. gray

[Twisted sparky]

I have an electrician using white as the grounded conductor of a 277/480V system. His argument is that it meets the NEC requirements. My argument against is that 110.12 reference to workmanlike manner includes following industry standards, which is white on a 120/240V system, and gray on a 277/480V system. The code doesn't call out brown, orange, yellow either, but it is the standard. I feel that 200.6 is a general reference to grounded conductors, and that which color is determined by the voltage of the system, as well as matching the existing building system.

 

[infinity]

IMO the first thing you should do is forget "workman like manner". The term in itself is so vague that it's unenforceable in any meaningful way.

If the building has two voltage systems, i.e. 480Y/277 and 208Y/120 or some other 120 volt variant, then mostly commonly you would identify each system with a particular color scheme. In that case you could use white for the 277 volt neutral and gray for the 120 volt neutral. Having said that most, including myself, would not do it that way.

Welcome to the Forum.

 

[roger]

as well as matching the existing building system.

Along with Infinity's post your last words are the key here, see 210.5

Roger

 

[dkidd]

Gray was used for a long time in the past when it wasn't Code compliant. I don't remember when it was changed.

See http://ecmweb.com/content/natural-gray-isnt-gray for a discussion of the way it used to be.

 

[cowboyjwc]

I tell a lot of people to not get hung up on "industry standards" as that's a good way to get hurt. No where is there any mention that 120/240 has the be black/red/blue and 277/480 is brown/orange/yellow. The code does mention now that if you have two different voltages in the building that you have to identify which colors are used and carry that through out.

There are only three mentions of color in the code book, white/gray=neutral, green=ground, orange=high leg or stinger.

 

[GoldDigger]

I tell a lot of people to not get hung up on "industry standards" as that's a good way to get hurt. No where is there any mention that 120/240 has the be black/red/blue and 277/480 is brown/orange/yellow. The code does mention now that if you have two different voltages in the building that you have to identify which colors are used and carry that through out.

There are only three mentions of color in the code book, white/gray=neutral, green=ground, orange=high leg or stinger.

You do not have to identify which colors are used unless you choose to use color to mark the systems.
Other forms of marking are allowed but color is usually the simplest to implement.

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[macmikeman]

Most buildings I go into that are more than 20 yrs old there is so much spaghetti existing wiring from alterations that the wiring color schedules are impossible to achieve without a total gut of every wire in the building practically. Especially when panels are shared between tenants of the same floors.

 

[growler]

I tell a lot of people to not get hung up on "industry standards" as that's a good way to get hurt. No where is there any mention that 120/240 has the be black/red/blue and 277/480 is brown/orange/yellow.

You got that right. Back about 1990 I worked at a large corporation where they refused to buy different color wire for the 277/480 so everything was black, red and blue.

There reasoning was that their other buildings had been done that way and they could see no reason to change. Seemed like a dumb reason to me but they were buying the wire.

 

[cowboyjwc]

You do not have to identify which colors are used unless you choose to use color to mark the systems.
Other forms of marking are allowed but color is usually the simplest to implement.

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210.5(c)(1)

 

[cowboyjwc]

You got that right. Back about 1990 I worked at a large corporation where they refused to buy different color wire for the 277/480 so everything was black, red and blue.

There reasoning was that their other buildings had been done that way and they could see no reason to change. Seemed like a dumb reason to me but they were buying the wire.

Yep, the only way you would know is by the neutral color and then you still don't know the voltage, until you check.

 

[peter d]

You got that right. Back about 1990 I worked at a large corporation where they refused to buy different color wire for the 277/480 so everything was black, red and blue.

There reasoning was that their other buildings had been done that way and they could see no reason to change. Seemed like a dumb reason to me but they were buying the wire.

In Canada they use black, red and blue for both 120/208 and 347/600. It's perfectly legal by the CEC.