phasing
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mike.oquinn
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Re: phasing
The original phase color coding was dropped mid-1980's with more emphasis on grounded/grounding color identification. It was thought a competent electrician would avail himself/herself with means to identify phasing if necessary.
But look at 210.4(D). This requires "identification" of phase conductors if more than one system is present in a building. In the 1996NEC, the FPN listed methods of "identification", such as color coding. The FPN has since been absorbed into the section in the 2002NEC.
This means you can use color coding if you must "identify".
It is interesting how manufacturers latch onto NEC requirements, using some for purposes the NEC did not intend. For instance, the colored plastic caps on RMC is marked based on the "old color code" for under 300V:
A-phase (Black) is used for 1/2" (the first conduit size), 1-1/2", 2-1/2", and 3-1/2" RMC
B-phase (Red) is used on 3/4" (the 2nd conduit size), and 1-1/4"
C-phase (Blue) is used on 1" (the 3rd conduit size), 2", 3", 4", 5", and 6"
When IMC came out, the color caps copied the "old color code" for over 300V:
A-phase (Brown) is used for 1/2" (the first conduit size), 1-1/2", 2-1/2", and 3-1/2" RMC
B-phase (Orange) is used on 3/4" (the 2nd conduit size), and 1-1/4"
C-phase (Yellow) is used on 1" (the 3rd conduit size, 2", 3", and 4"
This makes it easy to determine conduit sizing and type from a distance ... and leaves a memory of the old days.
The original phase color coding was dropped mid-1980's with more emphasis on grounded/grounding color identification. It was thought a competent electrician would avail himself/herself with means to identify phasing if necessary.
But look at 210.4(D). This requires "identification" of phase conductors if more than one system is present in a building. In the 1996NEC, the FPN listed methods of "identification", such as color coding. The FPN has since been absorbed into the section in the 2002NEC.
This means you can use color coding if you must "identify".
It is interesting how manufacturers latch onto NEC requirements, using some for purposes the NEC did not intend. For instance, the colored plastic caps on RMC is marked based on the "old color code" for under 300V:
A-phase (Black) is used for 1/2" (the first conduit size), 1-1/2", 2-1/2", and 3-1/2" RMC
B-phase (Red) is used on 3/4" (the 2nd conduit size), and 1-1/4"
C-phase (Blue) is used on 1" (the 3rd conduit size), 2", 3", 4", 5", and 6"
When IMC came out, the color caps copied the "old color code" for over 300V:
A-phase (Brown) is used for 1/2" (the first conduit size), 1-1/2", 2-1/2", and 3-1/2" RMC
B-phase (Orange) is used on 3/4" (the 2nd conduit size), and 1-1/4"
C-phase (Yellow) is used on 1" (the 3rd conduit size, 2", 3", and 4"
This makes it easy to determine conduit sizing and type from a distance ... and leaves a memory of the old days.
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