Wire colors in industrial machines

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megloff11x

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The standard practice is that 208Y120 is either all black, or black, red, and blue for the lines. 480/277 is either all black or they use brown, orange, and yellow. Usually because the wire is so fat and the price of spools being what they are you just put colored tape on the ends so you can keep track of which line is which. Ground is either bare copper, green, or green/yellow stripe, and can be black with green tape for fat wire. Neutral is usually white or white tape.

In NFPA79 they recommend that Orange or Yellow be almost exclusively used to indicate line Voltage that is NOT de-energized when the main disconnect is off. This would conflict with standard or optional color coding for 480/277.

Further, red is for lower Voltage AC (like a 24VAC on an EMO loop) and blue is recommended for DC Voltages. These could be confused with lines B&C of a 208Y120 3-phase.

They don't suggest a color for the return wire for DC Voltages, which may or may not bond to the incoming ground.

As long as I provide a color chart...

But after all this my question is, what do you like for your wire color schemes when you set up a machine, and how do you deal with the shared colors issue?

Matt
 
Meg,
You are talking about:
Wire colors in industrial machines
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Within the Industrial Controller itself, which UL508A has "particially" adopted the automotive NFPA-79 as a standard. I say particially because all power circuits regardless of voltage shall be black and gray or white with stripes for grounded AC power current carrying power circuit conductor regardless of voltage (66.5.3 (a). I know it's wierd that flies in the face of the NFPA-79, as you previously posted, but we are talking about the inside of the industrial. It is my understanding that you have to follow this color-coding or be inviolation of NEC 409 & UL508A.
Sorry.....
Just my $.02
 
megloff11x said:
The standard practice is that 208Y120 is either all black, or black, red, and blue for the lines. 480/277 is either all black or they use brown, orange, and yellow.

In NFPA79 they recommend that Orange or Yellow be almost exclusively used to indicate line Voltage that is NOT de-energized when the main disconnect is off. This would conflict with standard or optional color coding for 480/277.
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I don't feel that power and control colors are in conflict; orange and yellow in NFPA79 are, in MY experience and designs, for control circuits only.

megloff11x said:
Further, red is for lower Voltage AC (like a 24VAC on an EMO loop) and blue is recommended for DC Voltages. These could be confused with lines B&C of a 208Y120 3-phase.
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I use red for AC control through 115VAC with white for "neutral" or common, usually grounded.

megloff11x said:
They don't suggest a color for the return wire for DC Voltages, which may or may not bond to the incoming ground.
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I've seen solid blue, blue with a white stripe, white with a blue stripe, and white used. My PREFERENCE is either of the striped. I see solid blue used over 90% of the time.

megloff11x said:
But after all this my question is, what do you like for your wire color schemes when you set up a machine, and how do you deal with the shared colors issue?

Matt
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There is an old NEMA standard.

Under MG1 - 2.41 I have the following for single phase -

T1 - Blue
T2 - White
T3 - Orange
T4 - Yellow

T5 - Black
T8 - Red
P1 - No color assigned
P2 - Brown

The information may be a little dated, but might be a good start point in searching a reference. It comes out of an old rewind book I have laying around.
 
NFPA 79 suggests:
Black = ungrounded at line voltage (120, 240, 480 does not matter)
Red = ungrounded AC at less than line voltage (like control circuits)
Blue = ungrounded DC control

NFPA 79 requires:
Yellow = ungrounded conductors that remain energized
Orange = ungrounded conductors that remain energized
Green = grounding conductor (yellow stripes are optional)
White or Gray = grounded AC conductor (stripes matching ungrounded conductor are optional)
White w/ blue stripes = grounded DC circuit
White w/orange or yellow = grounded that remains energized
Any other color w/(3) white stripes = grounded AC conductor
 
While the NFPA-79 does include color-coding for wires and adopted by the automotive manufacturers, it is considered a consesus (agreement in opinion), not a standard for Industrial Controllers out of the automotive industry. The NEC 409 & UL508A is a "Standard"
all power circuits regardless of voltage shall be black and gray or white with stripes for grounded AC power current carrying power circuit conductor regardless of voltage (66.5.3 (a).
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Additionally you can not use a standard power Distribution Block in the Feeder circuit, and you must recognize torque, based upon screw size.
Just my $.02
 
For anyone reading this thread. Jim Dungar is correct on all of the NFPA-79 color coding. UL508A in section 66.9.1 states the exact same. So this is a required "Standard" for Industrial Control panels.
I mis-spoke earlier on this subject.
DR
 
The white with blue stripes is a bit hard to come by. Also, I may not ground the DC return wire due to potential noise issues. In the NEC they allow "taping" the different phases at the ends - I suppose so you know which black wire is what phase on the other end of the 100ft conduit run.

NFPA 79 does appear to have exceptions if the wire insulation color isn't available or it's not conducive to your situation. Under 14.2.4.3 they list the exceptions and I assume they apply to all of 14.2, not just the last bit.

I think if the rules were cast in stone, all of the colors they'd prefer would be available off the shelf.

Matt
 
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