# Conductor Color Coding Standard



## joebanana (Dec 21, 2010)

Usually control wiring is one color, grey SIS, with wire marker numbers designating it's location, or terminal number. Yellow is "C" phase 480v., not usually used for control purposes.


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## splatz (May 23, 2015)

You'll get different answers but IMO NFPA 79 is a standard for machine equipment manufacturers. It might help you figure out what's going on if you're trying to repair a machine, but I'd never assume the manufacturer followed any color coding standard. It would only make sense to try to figure out and follow the manufacturer's scheme when repairing their machine. It would apply in control panels that are part of the machine supplied with the machine, but not to controls put together in house to control and supply the various machines. 


The scope of NFPA 79: 



> ...intended to minimize the potential hazard of electrical shock and electrical fire hazards of industrial metalworking machine tools, woodworking machinery, plastics machinery and mass produced equipment, not portable by hand.


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## brian john (Mar 11, 2007)

joebanana said:


> Usually control wiring is one color, grey SIS, with wire marker numbers designating it's location, or terminal number. Yellow is *OFTEN USED FOR* "C" phase 480v., not usually used for control purposes.


Fixed it for you

You can use yellow if you want but not mandatory.

For inside control cabinets, we use white or gray SIS


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## scotch (Oct 17, 2013)

Usually in custom HVAC units controls I worked with it was BLACK....black for 600 vac , black for 120 vac , and black for 24 vac.....grounds ? Whats that about? Only field add-ons were any other colour.


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## bill39 (Sep 4, 2009)

Per NFPA, orange is for foreign voltage or conductors that remain hot when main disconnect is off.


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## paulengr (Oct 8, 2017)

You'll find a lot of things in NFPA 79 are not right or not used.

Red/black/blue is the Canadian standard for pretty much all 3 phase up to 600 V. Black becomes standard at one point to save on inventory costs then you phase tape it. The US standard is Brown, orange, yellow but there is a rule for 230/208 that nobody follows that is a different sequence from the Canadian standard so leads to confusion. Multiconductor cables are all over the place color wise.

Battery DC automotive is red/black and the European standard is blue/brown but a lot of shielded cable comes as black/white.

So good luck with color coding because there basically is no standard.

Exception: FAA mandates all wiring no matter the purpose is white hand stamped every 3 feet with a 5 digit wire number. What a pain. NEC and others have specs on neutrals and grounds but almost nothing else.


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## bill39 (Sep 4, 2009)

In the USA, color coding can be so confusing. 
The NEC is very open. 
There are what I call “traditional” standards for residential & commercial. 
Many industrial plants are similar but different. 
Municipal WWTP and WTP designed by consulting engineers usually use UL-508A standards. And then the NFPA is similar but different to UL-508A.


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## MechanicalDVR (Dec 29, 2007)

joebanana said:


> Usually control wiring is one color, grey SIS, with wire marker numbers designating it's location, or terminal number. Yellow is "C" phase 480v., not usually used for control purposes.


I've seen plenty if 24V control panels with Yellow conductors as well as brown, blue, and grey.

Many equipment manufacturers just use white with various color tracers.


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## frenchelectrican (Mar 15, 2007)

MechanicalDVR said:


> I've seen plenty if 24V control panels with Yellow conductors as well as brown, blue, and grey.
> 
> Many equipment manufacturers just use white with various color tracers.


I second that part and I have ran into a lot of 24 volt control circuit typically yellow and grey ( sometime white too so be aware of that) on AC side but DC it goes blue and brown which I ran into on DC side often over here.


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## electrialguy (Dec 16, 2018)

*Found an Answer for Question 2*

Question 2 Answer:
"Yellow was used in the 1997 edition, yellow or orange in 2002, and only orange in 2007 and all the editions that followed." 
Source: NFPA 79 Handbook 2015 Edition. Page 137

Still need an answer for question 1 please.


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