AC conductor color & identification standards

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SunFish

Member
Location
ID
I have been trained that while it is not required by the NEC the following colors should be used for the line conductors in AC systems:

L1 - Black (split phase or 208 three phase)
L2 - Red (split phase or 208 three phase)
L3 - Blue (208 three phase)


480/277 L1 - Brown
480/277 L2 - Orange
480/277 L3 - Yellow


It is my understanding that while this is not NEC required it is "industry standard" and should be followed to provide a higher quality of work with easier serviceability.

Is this truly industry standard that is advisable to follow or is this just a local standard that may differ throughout the country?
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
I have been trained that while it is not required by the NEC the following colors should be used for the line conductors in AC systems:

L1 - Black (split phase or 208 three phase)
L2 - Red (split phase or 208 three phase)
L3 - Blue (208 three phase)


480/277 L1 - Brown
480/277 L2 - Orange
480/277 L3 - Yellow


It is my understanding that while this is not NEC required it is "industry standard" and should be followed to provide a higher quality of work with easier serviceability.

Is this truly industry standard that is advisable to follow or is this just a local standard that may differ throughout the country?
It's local. For example, Austin and San Antonio both have local addenda to the NEC dictating that the hot legs of a split phase 240VAC system be red and black, but they are opposite from each other on which is which.
 

celtic

Senior Member
Location
NJ
It is my understanding that while this is not NEC required it is "industry standard" and should be followed to provide a higher quality of work with easier serviceability.

Is this truly industry standard that is advisable to follow or is this just a local standard that may differ throughout the country?
My opinion is that it is a standard
[up to 240]~ Black-red-blue..white neutral
[up to 480]~ Brown-orange-yellow...grey neutral

I think Southwire makes BX/MC with these colors ...

This standard goes right out the window when dealing with entities such as a DOT.
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
So when do I get to use purple? Such a pretty color...:)
I did a project once for a shipyard. All the AC control wires were purple.

As best I can tell, other than grounded, ground wires, and high legs there is no "standard", except on a place by place basis, and a few localities as someone else mentioned. Which means it is not really standard.
 

realolman

Senior Member
I made a big wire cart on wheels that holds about 50 rolls of wire depending on the size....as many different colors as I can get. Usually it will end up with three each of several different colors and white and green. It 's a good thing.

I never could see any point in worrying about what color the wires were.

Always seemed to me different is better. It's just as easy to pull in a bunch of different colors as a bunch of one color, and then you don't have to fool around with wire markers.... now there's a PITA.
 
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jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
It's local. For example, Austin and San Antonio both have local addenda to the NEC dictating that the hot legs of a split phase 240VAC system be red and black, but they are opposite from each other on which is which.
Is that a joke? The part about which is which?
 

kwired

Electron manager
Location
NE Nebraska
I made a big wire cart on wheels that holds about 50 rolls of wire depending on the size....as many different colors as I can get. Usually it will end up with three each of several different colors and white and green. It 's a good thing.

I never could see any point in worrying about what color the wires were.

Always seemed to me different is better. It's just as easy to pull in a bunch of different colors as a bunch of one color, and then you don't have to fool around with wire markers.... now there's a PITA.
That has been the way I generally have done things in the past. Raceway full of conductors all same size - the three blacks are one motor, the three reds are another motor, and so on. If a motor runs backward when connected reverse two leads at any point that is convenient. Now if I have more than one voltage system I can still do that but also still need to identify each conductor as system and phase somehow. Conductor color is not the only method to do so.

But I do seem to find myself using say brown, orange, yellow and if there are multiple circuits of same size conductor in same raceway using colored tape to "bundle" each individual circuit. Although I still like the old idea of three conductors of same color for one motor better. The most you will generally screw up in routing or terminating is wrong rotation of motor, which I feel is much better than accidentily getting one conductor of a set to the wrong motor. I bump motors to check rotation even if I am sure which way it is supposed to run - sometimes you are still wrong. If load can not be run backward - rotation still needs verified before the first run somehow or there will be a problem if it is wrong.
 

iwire

Moderator
Staff member
Location
Massachusetts
I have been trained that while it is not required by the NEC the following colors should be used for the line conductors in AC systems:

L1 - Black (split phase or 208 three phase)
L2 - Red (split phase or 208 three phase)
L3 - Blue (208 three phase)


480/277 L1 - Brown
480/277 L2 - Orange
480/277 L3 - Yellow


It is my understanding that while this is not NEC required it is "industry standard" and should be followed to provide a higher quality of work with easier serviceability.

Is this truly industry standard that is advisable to follow or is this just a local standard that may differ throughout the country?

Certainly common in many areas but also not a standard. Many areas use a purple for a phase conductor.
 

jeremysterling

Senior Member
Location
Austin, TX
So I take it that one of those jurisdictions says that Leg 1 is black and the other says that Leg 2 is black? It makes no practical difference whatsoever to any equipment, does it? That's why I asked if it was a joke.
The Nation of Canada and the City of Austin have the same LV color code.

L1, L2, L3 = Red, Black, Blue

However, we are not similar with our HV.

L1, L2, L3 = Brown, Yellow, Purple

Residential single phase is also L1 = Red
 

BillK-AZ

Senior Member
Location
Mesa Arizona
The 2011 NEC Handbook has these colors illustrated, but not required, in EXHIBIT 200.3. Part of Art. 200.6(B).

If there is more than one nominal voltage system, then Art. 210.5(C) applies. Color coding is recognized as a popular option. Color-coded tape is illustrated as an example.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
So I take it that one of those jurisdictions says that Leg 1 is black and the other says that Leg 2 is black? It makes no practical difference whatsoever to any equipment, does it? That's why I asked if it was a joke.
'Tis true and you are correct that it makes no difference to equipment, only to electricians who are working in the jurisdictions of both AHJ's.
 

kwired

Electron manager
Location
NE Nebraska
'Tis true and you are correct that it makes no difference to equipment, only to electricians who are working in the jurisdictions of both AHJ's.
On single phase equipment I cant ever recall caring to know which line was which. By that I mean when I am at a piece of equipment I may need differentation between L1 and L2 within the equipment but I could care less which is actually the L1 and L2 back at the service equipment.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
On single phase equipment I cant ever recall caring to know which line was which. By that I mean when I am at a piece of equipment I may need differentiation between L1 and L2 within the equipment but I could care less which is actually the L1 and L2 back at the service equipment.
Exactly. I mean, I have always connected the black to L1 on inverters just for consistency's sake, but I'm pretty taken-aback by the notion that I could fail an inspection because I put red there instead.
 
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