Pulling 12-2 M/C cable blk, wh, grd for 277 V. Lighting

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zappy

zappy

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I told the lead guy, hey were pulling the wrong colors. He said well phase tape it at the panel. Im thinking, you cant phase tape the wh. Neutral gray. Also shouldnt every termanation be phase taped? Like in the lights? So what does the code say? Thank you for your help.
 
Not sure the code addresses this but Look at 200.7(C). I realize this allows the white or gray conductor to be marked as an ungrounded conductor so I don't see the issue with marking a white wire with gray as a neutral.

I realize I am interpreting here not following the wording of the code.
 
I believe theres a section that says anything below 4awg, the neut. has to be solid. Cant be phase taped.
 
When reidentifying any conductor by taping, painting, printed labelling, etc. the code requires that same reidentification to be done at each box, condolet, panel, etc. where that wire is "accessible", not just where it terminates. :(
 
zappy said:
I told the lead guy, hey were pulling the wrong colors. He said well phase tape it at the panel. Im thinking, you cant phase tape the wh. Neutral gray. Also shouldnt every termanation be phase taped? Like in the lights? So what does the code say? Thank you for your help.
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To go along with what ActionDave said, The NEC doesn't care what color you use for 277, either white or gray. The ungrounded conductor can be any color

Roger
 
I assume that you are in the situation with two voltages in the same building, probably 120/208V and 277/480V. If that is the case then:

200.6 Means of Identifying Grounded Conductors.

(D) Grounded Conductors of Different Systems.
Where grounded conductors of different systems are installed in the same raceway, cable, box, auxiliary gutter, or other type of enclosure, each grounded conductor shall be identified by system. Identification that distinguishes each system grounded conductor shall be permitted by one of the following means:

(1) One system grounded conductor shall have an outer covering conforming to 200.6(A) or (B).

(2) The grounded conductor(s) of other systems shall have a different outer covering conforming to 200.6(A) or 200.6(B) or by an outer covering of white or gray with a readily distinguishable colored stripe other than green running along the insulation.

(3) Other and different means of identification as allowed by 200.6(A) or (B) that will distinguish each system grounded conductor.

The means of identification shall be documented in a manner that is readily available or shall be permanently posted where the conductors of different systems originate.

If that is the case you need to decide which rule is more important: not taping small conductors or identification of voltages. I would go for 200.6(D) id the voltages. NOTE: if you are taping the neutral gray, would you not also tape the hot wire?

As a matter of curiosity what sort of installation has 277V and NM cable?
 
IMO putting a gray tape mark on a white conductor (whether in a cable method or not) is not "re-identifying" the fact it is a grounded conductor, it is further clarification of the use of a grounded conductor. One could have a raceway with several white conductors installed, nothing wrong with putting numbers, or other markings on them to be able to identify the purpose of each individual conductor, and the overall white coating still identifies it as a grounded conductor.

white for 120 gray for 277 is not an NEC requirement, it is just one common industry standard. NEC only requires they be separately identified for voltage and system somehow, and that identification method be same throughout a premises.
 
arcsnsparks98 said:
Correct me if I am wrong but isnt NM limited to 150 volts to ground?
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Look at the jacket on any NM cable - it is a 600 volt wiring method. However not many instances where over 150 to ground is being used is a place where NM is going to be used in general. Outside of dwellings NM must be in at least 15 minute finish and can not be used above suspended ceilings. Those two items generally make it somewhat pointless to even have NM cable on site for other then dwellings, even though there are places it can otherwise be used at the site, but they are somewhat limited uses.
 
fmtjfw said:
If you are using MC, you can get MC with the proper colors.
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That is a convenience and maybe looks more professional to some, but is not a NEC requirement to use such cables, and there is no "proper colors" in NEC other then grounded conductors must be white or gray, further identification may be required but how is up to designer/installer.
 
kwired said:
Look at the jacket on any NM cable - it is a 600 volt wiring method. However not many instances where over 150 to ground is being used is a place where NM is going to be used in general. Outside of dwellings NM must be in at least 15 minute finish and can not be used above suspended ceilings. Those two items generally make it somewhat pointless to even have NM cable on site for other then dwellings, even though there are places it can otherwise be used at the site, but they are somewhat limited uses.
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FWIW in some parts of Massachusetts NM is very common for 277/480 volts. Even SER for 120/208 commercial. I have no idea why it was allowed but its what I have seen.
 
kwired said:
He did, the use of NM for a 277 volt is not all that likely but not impossible though. Temporary wiring is maybe a greater possibility.
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It depends a lot on local methods. As mentioned in New England you will find a lot of commercial buildings wired with NM. 277 volt lighting, 480 volt 3 phase loads pretty much anything. If the circuit is larger SE or SER cables would be used.

This was allowed by the NEC up until either the 2002 or 2005 NEC. Mass. amended the changes so we can still do it in many cases. However it seems job specifications have eliminated NM.

IMG_1505.jpg


One of the big keys in understanding how the above is (or was) allowed is understanding this section.

334.10(3) Other structures permitted to be of Types III, IV, and V
construction except as prohibited in 334.12. Cables
shall be concealed within walls, floors, or ceilings that
provide a thermal barrier of material that has at least a
15-minute finish rating as identified in listings of fire rated
assemblies.
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The bit about '15-minute finish rating' is a fairly recent change.
 
mbrooke said:
FWIW in some parts of Massachusetts NM is very common for 277/480 volts. Even SER for 120/208 commercial. I have no idea why it was allowed but its what I have seen.
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It often is not all that practical to use NM in other then dwelling units. You could run it in sheetrocked walls and ceilings in many places, but if you have exposed wiring, a suspended ceiling, environmental air spaces - you need to adapt to a different wiring method for those areas. I have not run NM for 277/480 that I can recall other then maybe for temporary purposes, but have done other commercial wiring a time or two in NM in walls, stubbed out of wall above suspended ceiling and later put j-boxes and run EMT in the ceiling. I wouldn't have a problem dropping a 277/480 volt outlet down such a wall in NM cable - just don't seem to run into that need hardly ever in most of what I do.
 
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