Today is...
Saturday, October 21, 2017
Welcome to, the global online
community of automation professionals.
Featured Video...
Featured Video
A demonstration of EtherCAT control of linear motors using the CTC EtherCAT master.
Our Advertisers
Help keep our servers running...
Patronize our advertisers!
Visit our Post Archive
wire colors in control cabinets
Is there any published wire color standards for inside a control cabinet with PLC's, power supplies, relays etc. ...
By Andrey, Bob on 26 January, 2001 - 2:09 pm

I have looked for Class of wires in the NEC book, articles in 725, but found nothing about the colors of wires for different voltage levels. Such as 115Vac from the breaker is Black and White, all 115Vac control wiring is RED, all DC control is Blue wires etc. Is there any published wire color standards for inside a control cabinet with PLC's, power supplies, relays etc. If so, where can I find this publication, is there a web site? Bob

By Randy Ransom on 26 January, 2001 - 11:12 pm

Bob, NFPA 79 sections 16.1.2 and 16.1.3 have information that may help. For European standards try IEC 204-1. There are numerous places to get the NFPA standard. I found this one: with a quick yahoo search. Regards, Randy Ransom

See 'NFPA Part 79' If you would like me to post the colors from the code, let me know.

By Kevin Hammond on 29 January, 2001 - 7:47 am

Bob, Take a look at NFPA 79 - "Electrical Standard for Industrial Machinery" It has what you are looking for along with a lot of other useful information. I think you can order it from the NFPA website. Kevin

By Randy DeMars on 29 January, 2001 - 3:21 pm

This is spelled out in the "Wiring Methods and practices" chapter of NFPA 79 Electrical Standard for Industrial Machinery. This document can be ordered at or 1-800-344-3555. (I sincerely hope that the mention of NFPA does not rekindle the "Why aren't standards free?" debate again...)

Don't forget white for grounded AC Neutral, green for ground, and the most important of all, IMHO, yellow for wires with hazardous voltage supplied from a source external to the panel. I have also seen blue with white stripe for DC common, not a bad idea. Bill Sturm

By Dale Witman on 30 January, 2001 - 5:13 pm

Bob, Look at JIC standards or IEC standards from Europe. They are slightly different, but each seems to have some good guidelines. Dale

By Stephen Wright on 31 January, 2001 - 1:58 pm

I rely on NFPA 79 for color codes, IEC 204-1 for equipment outside the US. I've always had difficulty getting Light Blue or White w/Blue stripe wire for grounded DC conductors, so I cheat and use blue.

By Tony Giammarinaro on 9 July, 2001 - 8:06 pm

Since our machinery is going to Europe, I will rely on IEC 204-1. Is there a site where I can order this standard from?


Manhatten Wire is an alright source for white with blue stripe wire (Part# M214-96);Olympic Wire is a better source. The Olympic part number is 363-96 for the white/blue stripe. I am sure these are part numbers for 18AWG hookup wire (600V-rated, PVC insulation.)