[RE-wrenches] useful info on wire color coding

[Jason Szrom]

My 2 cents on this issue which I have encountered on numerous occasions. Here in NYC the majority of service switch installs agree with the convention of BLACK, RED, BLUE. However, I have seen a few older service switches with the reverse, BLUE, RED, BLACK.

The only documented place I have ever seen this written is UGLY's 2005, pg 14, and that refers you to "local ordinances or specifications."

For our PV installs we use the same color coding as the existing utility service switches for that building, 210.5(C) and 215.12(C).

Regards,

Jason M. Szrom, PE
Engineer
Solar Energy Systems, LLC
718-389-1545 x13


-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of R Ray Walters
Sent: Sunday, August 22, 2010 2:49 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] useful info on wire color coding

I found utter world wide confusion upon more research on this issue.
http://en.wikipedia.org/wiki/Three-phase_electric_power has a table that lists color coding for different countries, US is black, red, blue, (common practice), 
while our neighbors in Canada, use Red, black, blue.☺  Europe is completely wild. 

430.97B requires that the phase arrangement of the legs be ABC from left to right in the disconnect box, but no color coding is mentioned. Apparently color coding of phases was dropped from the code in 1975. (please correct me on all of this, oh fellow older wrenches) 
I found reference to 406.3 E, but I  only have a 1999 code book with me at the moment, and that's not in the old code.

I noted that Fluke's 9040 phase rotation meter, has no color coding, just 3 black leads.
New Mexico practice was often just 3 blacks as well, except for a Delta high leg system, where the high leg is required to be marked in Orange (as per code).

http://www.3phasepower.org/3phasewiring.htm also shows black, red, blue for the US, so I think that would be the smart way to color code here, even if it's not code specified.

As the others pointed out, checking phase rotation, at the terminals as close to the equipment as possible before throwing the switch is the most important thing. Anywhere along the line, the wires could have been switched, thus reversing the phase rotation.

R. Walters
ray at solarray.com
Solar Engineer




On Aug 22, 2010, at 6:52 AM, Richard L Ratico wrote:

> Marco,
> If I understand your question, not sure I do, my answer is, there is no
> requirement for such a relationship.
> 
> Repeat to yourself, what Darryl said:
> Always check rotation either with a rotation meter or with a motor by bumping
> the motor to check its rotation.
> 
> Dick says, ......Pay absolutely no attention to color coding as to how it might
> relate to phase rotation. If you trust 
> some pieces of colored tape, that you did not apply yourself, after checking
> rotation as above, you're bound to get bit in the backside.
> 
> ALWAYS check rotation either with a rotation meter or with a motor by bumping
> the motor to check its rotation.
> 
> Dick Ratico
> Solarwind Electric
> Bradford, VT
> 
> 
> --- you wrote---
> But I am still trying to determine if the black-red-blue and brown-orange-yellow
> sequences are appropriate for clockwise or counter-clockwise phase rotations.
> 
> marco
> --- end of quote ---
> 
> --- Darryl wrote:
> see previous post if looking at the shaft of the motor, CW is clock wise ie
> Black-red-blue but but just because you have thoes colors does not mean it was
> done correctly.^$A0 always check rotation either with a rotation meter or with a
> motor by bumping the motor to check its rotation.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
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