1968 NEC color code

[dnem]

I've seen written in various articles that the 1971 edition of the NEC had conductor color codes removed. For those of you with access to the 1968 edition, what was the color code in that edition ? Did it call out phase conductor colors ?

There are a multitude of places that state industry practice for phase colors are:
under 250v; black, red, blue
over 250v; brown, orange, yellow
but I can't find anywhere how those colors were originally determined. I'd like to know if they were in the 1968 NEC. I had also heard once, many years ago, that the colors originated from the IBEW but I can't seem to find any statement that confidently states where the common industry practice began

 

[bphgravity]

The first time this requirements showed up in the code was in the 1940 edition.

1968 NEC - Section 210-5:

"Where installed in raceways, as aluminum sheathed cable, as open work, or as concealed knob-and-tube work, the conductors of multiwire branch circuits and two-wire branch circuits connected to the same system shall conform to the following color code. Three-wire circuits - one black, one white, one red; four-wire circuits - one black, one white, one red, one blue; five-wire circuits - one black, one white, one red, one blue, one yellow. Where more than one mulitiwre branch circuit is carried through a single raceway the ungrounded conductors of the additional circuit may be of colors other than those specified. All circuit conductors of the same color shall be connected to the same ungrounded feeder conductor throughout the installation."

The rule was deleted from the 1971 edition and replaced with the following:

"It is recommended for a basic single wiring system that the following colors be used: 3-wire circuits, 1 black, 1 white and 1 red; 4-wire circuits, 1 black, 1 white, 1 red and 1 blue."

This "note" was deleted from the 1975 edition of the NEC.

 

[480sparky]

The color code was introduced in the 1937.

2014. Multi-Wire Branch Circuits - Color Code Branch circuits of any of the types recognized in this article may be installed as multi-wire circuits; provided one of the conductors of the circuit is an identified grounded conductor. Conductors of such multi-phase systems shall conform to the following color code: three-wire circuits - one black, one white on red; four-wire circuits - one black one white, one red, one yellow; five-wire circuits - one black, one white, one red, one yellow, one blue.

 

[GoldDigger]

Interesting that yellow and blue changed roles somewhere between 1937 and 1968.

 

[bphgravity]

The color code was introduced in the 1937.

2014. Multi-Wire Branch Circuits - Color Code Branch circuits of any of the types recognized in this article may be installed as multi-wire circuits; provided one of the conductors of the circuit is an identified grounded conductor. Conductors of such multi-phase systems shall conform to the following color code: three-wire circuits - one black, one white on red; four-wire circuits - one black one white, one red, one yellow; five-wire circuits - one black, one white, one red, one yellow, one blue.

Opps... Your right, 2104 of the 1937 edition!

 

[dnem]

So it seems that the original color code was not intended to require all 3phase panels to be filled with black, red, and blue but rather was specifically required for SHARED neutral multiwire branch circuit installations.

I'm going to guess that over 250v was chosen by someone [possibly the IBEW] who was just filling in the gaps based on what colors were still available and not yet assigned. If black, red, blue, white, and green were designated by code, then the remaining colors were brown, orange, yellow, purple, pink, grey. I would guess that pink was considered as too easily thought to be a off batch colored red and I wouldn't be surprised if purple was not as commonly available as it is now. And so by default, the remaing brown, orange, yellow, grey became the over 250v colors.

Is this the conclusion you reach ?

 

[Pharon]

Why did they remove this from the NEC? Seems like a good thing, from a safety perspective.

 

[480sparky]

Why did they remove this from the NEC? Seems like a good thing, from a safety perspective.

Stop and think of all the various voltage and phase combinations there are. Do you want a laundry list of colors for each?

 

[Smart $]

Stop and think of all the various voltage and phase combinations there are. Do you want a laundry list of colors for each?

I have to wonder which would be better. A list of colors for each configuration (including line assignments), or the potpourri of colors we can end up with now, especially when only one configuration is in use. I think the only thing that prevents the color schemes (or lack thereof) from getting out of hand is the general professionalism of tradespersons.

 

[Pharon]

Stop and think of all the various voltage and phase combinations there are. Do you want a laundry list of colors for each?

There really aren't all that many, at least not for most commercial and residential applications.

Single phase 240: Red/Black
3 phase 208: Red/Black/Blue
3 phase 480: Brown/Orange/Yellow

It would be nice if there was some sort of color scheme for medium voltage, too - like 4160V and 13.8kV. I have no idea what most people use for those.

 

[480sparky]

There really aren't all that many, at least not for most commercial and residential applications.

Single phase 240: Red/Black
3 phase 208: Red/Black/Blue
3 phase 480: Brown/Orange/Yellow
........

You just listed the ones you've worked with. There are plenty of others.

 

[mwm1752]

Was or is there a reference to marking at least 6" of lenght on a conductor at the termination?

 

[Pharon]

You just listed the ones you've worked with. There are plenty of others.

Define "plenty."

I've worked with others. The ones I listed, as I said though, cover MOST commercial and residential applications in the U.S. Perhaps, one might even argue, the vast majority. To hammer out classifications for those -- which are pretty much already used universally anyway -- would seem to me one of those safety issues that the NEC should be dealing with somewhere in their 800+ page treatise.

 

[480sparky]

Define "plenty."............

One more than what you can think of.



What purpose would requiring all those color codes serve?

 

[Pharon]

I'm not suggesting color codes for obscure voltages - just the ones most commonly used. Right now there is no Code requirement at all, which is absurd. At least with something simple like this, inspectors could flag an install for brown/orange/yellow on 208V or vice versa.

 

[Pharon]

Even implementing a range would be better than what's there now, like:

Less than 250V, red/black/blue

251V to 600V, brown/orange/yellow

That should cover at least 98% of all utilization voltage scenarios.

 

[GoldDigger]

Even implementing a range would be better than what's there now, like:

Less than 250V, red/black/blue

251V to 600V, brown/orange/yellow

That should cover at least 98% of all utilization voltage scenarios.

Except that you would have to violate that spec whenever you had more than one in either category.

 

[Pharon]

That could easily be covered with a note, "where more than one voltage within a category exists, alternate colors may be used, blah, blah, blah"

 

[iwire]

I am entirely against a code mandated color code.

In my opinion no one should be determining the voltage of a conductor by the color of the conductor. That would be a quick way to become complacent and get yourself into trouble.

 

[iwire]

Why did they remove this from the NEC? Seems like a good thing, from a safety perspective.

I think the opposite is true.