# Control Circuit Color Code



## Big John (May 23, 2010)

NFPA 79.

Black is line voltage.
Red is any reduced voltage within the same enclosure.
Blue is DC.
Yellow is a circuit supplied from an exterior source.
White is any grounded conductor, and can be marked depending on DC or remote source.

There may be others, but that's off the top of my head.


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## denny3992 (Jul 12, 2010)

Big John said:


> NFPA 79.
> 
> Black is line voltage.
> Red is any reduced voltage within the same enclosure.
> ...


We use blue with white stripe for dc -


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## Jlarson (Jun 28, 2009)

UL 508 

Black - ungrounded conductors operating at the supply voltage

Red - ungrounded AC control circuits at a voltage less than the supply 

White or grey - grounded AC conductor, any voltage

Blue - ungrounded DC control circuits

White with blue stripe - grounded DC conductor

Yellow - ungrounded control circuits or other wiring that may still be hot with the disconnect off

White with yellow stripe - grounded AC conductor that is hot with disco off

Green or green w/ yellow stripe - ground


NFPA 79

Black - ungrounded conductors operating at the supply voltage

Red - ungrounded AC control circuits at a voltage less than the supply 

White, grey or conductor with 3 white stripes on other then blue, yellow, green, or orange - grounded AC conductor, any voltage

Blue - ungrounded DC control circuits

White with blue stripe - grounded DC conductor

Yellow or orange - ungrounded control circuits or other wiring that may still be hot with the disconnect off

White with yellow stripe, white w/ orange - grounded AC conductor that is hot with disco off

Green or green w/ yellow stripe - ground


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## kf5aeo (Dec 4, 2011)

never mind wont cooperate for me


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## 123 (Oct 28, 2012)

AC power ...Black 
AC control ...red 
DC ...blue
DC grounded ...blue with white stripe 
external source ...yellow
ground ...green or green-yellow
grounded AC conductor ...white
I have seen a grounded AC conductor for control red


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## Big John (May 23, 2010)

123 said:


> ...I have seen a grounded AC conductor for control red


 Ayuh. Seems like most guys just make all the low voltage stuff red, regardless of grounded or ungrounded. I don't like that, but it is common.


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## denny3992 (Jul 12, 2010)

123 said:


> AC power ...Black
> AC control ...red
> DC ...blue
> DC grounded ...blue with white stripe
> ...


Sometimes blue with white stripe is hard to get so we use gray.... As dc-


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## union347sparky (Feb 29, 2012)

Usually the stuff I work on is so scabbed together and so old you can't tell what the color of the wire is anyway. I never had to learn a color code just learn how to trace out wires. This thread helped remind me that there is actually a color code. ;-). Would be cool to build a cabinet from scratch or work on one that used a color code.


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## Big John (May 23, 2010)

union347sparky said:


> ...Would be cool to build a cabinet from scratch or work on one that used a color code.


 After a couple of years of watching plant operators destroy well built control panels, I started having everyone put hasps and locks on all the cabinets we built. They looked good and worked right and dammit they were gonna stay that way.


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## denny3992 (Jul 12, 2010)

U mean like this?


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## eric7379 (Jan 5, 2010)

denny3992 said:


> U mean like this?
> 
> View attachment 20616


 
Looks good. What's the problem? 
Just kidding. Looks like somebody threw bowl of multi-colored spaghetti in that panel. 

In the second pic, are all of those mounted on the door? If so, . It is my personal preference, but I hate it when I see crap like that.


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## stuiec (Sep 25, 2010)

denny3992 said:


> U mean like this?
> 
> View attachment 20616


At least they left a map......or is that a Kleenex? :laughing:


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## Jlarson (Jun 28, 2009)

Big John said:


> Ayuh. Seems like most guys just make all the low voltage stuff red, regardless of grounded or ungrounded. I don't like that, but it is common.


If you don't bond the CPT secondary and have 2 secondary fuses that's the way to do it. Some are just stuck on that old way.


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## union347sparky (Feb 29, 2012)

denny3992 said:


> U mean like this?


That's exactly like the ones I work on.


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## denny3992 (Jul 12, 2010)

stuiec said:


> At least they left a map......or is that a Kleenex? :laughing:


It was a print.... But.... Wasnt exactly correct.. Uggghhh


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## 123 (Oct 28, 2012)

Big John said:


> NFPA 79.
> 
> Black is line voltage.
> Red is any reduced voltage within the same enclosure.
> ...


If you had a 460V supply and machine would have some 460V motors, and some 208V.
the transformer is on the top of the cabinet, and is wired through the cabinet.
Would you wire the 208V in red? (lower voltage than supply) or in black?

If a machine runs on 120VAC, and has 120VAC controls, would you wire the controls 
in black? (same voltage as supply), or in red?


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## Big John (May 23, 2010)

123 said:


> If you had a 460V supply and machine would have some 460V motors, and some 208V.
> the transformer is on the top of the cabinet, and is wired through the cabinet.
> Would you wire the 208V in red? (lower voltage than supply) or in black?
> 
> ...


 My understanding of that code is that it's meant to differentiate voltage systems within the cabinet. So if there was only one voltage present within the enclosure, everything got wired in black. 

However, if there was a CPT in the enclosure itself, even if the line voltage came in, went directly to fuses, and then went right to the CPT, that would be black, and everything on the CPT secondary would be red.


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## Fixastang (Sep 4, 2012)

*Exactly!!!*



denny3992 said:


> U mean like this?
> 
> View attachment 20616


That's exactly the type of stuff we are dealing with here at the WWTP. We have prints, but the bucket wiring has been "modified" the prints are virtually useless.

Many thanks to everyone for posting there comments!!! They are greatly appreciated. :thumbsup:


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## denny3992 (Jul 12, 2010)

Fixastang said:


> That's exactly the type of stuff we are dealing with here at the WWTP. We have prints, but the bucket wiring has been "modified" the prints are virtually useless.
> 
> Many thanks to everyone for posting there comments!!! They are greatly appreciated. :thumbsup:


Fortunately this was a retro job at my last job an not the wwtp i work at now..... Most at wwtp are much nicer


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