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US wire color 115VAC question
- Thread starter rQx
- Start date
Bit_Bucket_07
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To the best of my knowledge, code only demands color codes for the ground wire and the neutral wire in a single phase 120 VAC circuit. Black wire is typically used for voltage source wires, while other colors are typically used for control circuits.
The standard that I have most often encountered for 3 phase wiring is BK/OR/YL for 480 VAC circuits and BK/RD/BU for 240 VAC circuits, and this choice typically represents a client's preference.
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jraef
Member
Here is the wording in NFPA 79, the standard for industrial machinery control systems.
Phase color indication for power circuits varies by region, although BOY is pretty much the defacto standard for FIELD wiring. But keep in mind that unlike IEC world, we have MULTIPLE versions of 3 phase power configurations and that means different color schemes. 208Y120, 240/120 3 phase 4 wire, 240V 3 phase 3 wire Delta, 480Y277V, 480V 3 wire Delta, 600V 3 wire Delta and 600Y347V. Each has it's own color scheme and some local utilities require different color schemes from others. As a general rule, when building control panels, I leave all of the power leads black and unmarked, it's irrelevant until it is connected anyway.
Prior to this section were sections describing grounded current carrying conductors (Neutral) being White and groundING conductors being Green or Green/Yellow.
Phase color indication for power circuits varies by region, although BOY is pretty much the defacto standard for FIELD wiring. But keep in mind that unlike IEC world, we have MULTIPLE versions of 3 phase power configurations and that means different color schemes. 208Y120, 240/120 3 phase 4 wire, 240V 3 phase 3 wire Delta, 480Y277V, 480V 3 wire Delta, 600V 3 wire Delta and 600Y347V. Each has it's own color scheme and some local utilities require different color schemes from others. As a general rule, when building control panels, I leave all of the power leads black and unmarked, it's irrelevant until it is connected anyway.
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This confuses me abit:
14.2.4.1* Ungrounded circuit conductors that remain energized
when the supply disconnecting means is in the off
position shall be consistently applied as either ORANGE or
YELLOW. These color identifications shall be strictly reserved
for this application only.
So yellow or orange shall be strictly reserved for conductors that remain energized when the supply is off. But then again the 3x480V is supposed to be black orange and yellow. It doesn't add up or do i interpret this wrong?
14.2.4.1* Ungrounded circuit conductors that remain energized
when the supply disconnecting means is in the off
position shall be consistently applied as either ORANGE or
YELLOW. These color identifications shall be strictly reserved
for this application only.
So yellow or orange shall be strictly reserved for conductors that remain energized when the supply is off. But then again the 3x480V is supposed to be black orange and yellow. It doesn't add up or do i interpret this wrong?
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jraef
Member
Timbert
Member
Brown, Orange, Yellow is a common method for designating the conductors of a three phase system in the US. It is NOT required by the US national electrical code, which governs premises and building installations which does not include industrial machines.
NFPA 79 contains requirements for industrial machines, including industrial control panels.
Outside the panel (off the machine), Brown, Orange, Yellow may be used to permanently identify ungrounded conductors. Inside the panel, Black shall be used to identify ungrounded conductors (at line voltage). Yellow or Orange shall be used only for ungrounded conductors that remain energized when the supply disconnecting means is in the off position.
What your customer is asking for is not consistent with US codes.
NFPA 79 contains requirements for industrial machines, including industrial control panels.
Outside the panel (off the machine), Brown, Orange, Yellow may be used to permanently identify ungrounded conductors. Inside the panel, Black shall be used to identify ungrounded conductors (at line voltage). Yellow or Orange shall be used only for ungrounded conductors that remain energized when the supply disconnecting means is in the off position.
What your customer is asking for is not consistent with US codes.
Thanks for clarification! So to sum this up I'll use the following inside the cabinet:
3x480vac supply - all black
120vac hot - black
120vac neutral - white
120vac control - red
Voltage when supply off - yellow or orange
24vdc - dark blue
0vdc - darkblue/white
Protective earth - yellow/green or is it green?
Is this end of discussion?
jraef
Member
The 120V Hot black bothers me. We're I to go into that panel, I would assume that to be 480V and disconnected by the Main. For example, the 480V conductors feeding the primary of a control power transformer should be black. I don't know where that "120V Hot = black" came from, that's totally foreign to me and I would say most industrially trained electricians. In fact I still don't understand what it means in this context. If it is derived from the CPT it should be red, if it comes in from somewhere else it should be yellow or orange.
The only thing I can think of is that if you have a panel where 120V is the HIGHEST voltage coming into the panel, i.e. controls only, no 480V or 240V power, then IT (120V) becomes the "line voltage" and would be black.
The only thing I can think of is that if you have a panel where 120V is the HIGHEST voltage coming into the panel, i.e. controls only, no 480V or 240V power, then IT (120V) becomes the "line voltage" and would be black.
I don't know either, and they don't know how the cabinet are designed.
But in some of our control panels we have both 480V and 120V supply that is disconnected by a 6 pole main breaker. So in this case both 480V and 120V would be "line voltage"? Thus making the 120V black?
But in some of our control panels we have both 480V and 120V supply that is disconnected by a 6 pole main breaker. So in this case both 480V and 120V would be "line voltage"? Thus making the 120V black?
We use either BROWN ORANGE YELLOW for 480V or black wire with a label L1,L2,L3. White is used for the neutral. Red is used for 110V control voltage, but we use black if we need wire larger than a 16AWG, with a label. This way we only have to stock 3 reels of black, 1 reel of white, and 1 reel of green of 14, 12, and 10 AWG wire.
We stock lots of different colors of 16AWG for control wiring, but only black, white, and green for larger gauges.
We stock lots of different colors of 16AWG for control wiring, but only black, white, and green for larger gauges.
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