Electrical wiring color code standards

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Thread Starter

Larry Grayson

I have a Eng. that is trying to use color coding different to what I was always told to use as the standard. Can any one direct me to a book or web site with such coding or tell where to find it in the code book. Red is AC and Blue is DC.
 
V

Verhappen, Ian

This thread has been posted before and includes reference to several international standards.

Ian Verhappen
 
M

Matthew Hyatt

For all of the UL listed panels I have worked on, designed and such I used the following:

Black = AC hot
Red = switched AC hot
Yellow = AC hot from a another source - another control panel as an example.
White = neutral
red w/white tracer = switched neutral
Green or green w/ yellow tracer = ground/earth ground

blue = DC voltage, ie, 12vdc, 24vdc
white w/blue tracer = dc common

Brown = AC 3 pahse - phase A
Orange = AC 3 pahse - phase B
Yellow = AC 3 Phase - phase C

shileds: think of current loops
2 cond
clear or red = +
black = -(neg)
3 cond
red = power (24vdc typically for transducers)
clear = + (signal output)
black = - (signal common)

Hope this helps, oh, and any panel I have design and wired this way is easily understaood by 99% of all service and electrical people I have worked with.
 
If you are in the U.S., the color codes are printed in NFPA 79 for industrial machinery. I'm not sure where, or if, it is listed in the NEC.

Also, Matthew's post looks correct to me.
 
R
Since our control panels are fabricated and listed under
Industrial Control Panels - UL508A, I have to use the
following color coding.

In section 66.5.3, the UL508A standard lists the following
color coding for internal power wiring.

Black - all ungrounded control power circuit conductors
regardless of voltage
White or natural grey - grounded AC current-carrying power
circuit conductor, regardless of voltage

In section 66.9, the UL508A standard lists the following
color coding for internal control wiring.

Black - all ungrounded control circuit conductors operating at the supply voltage
Red - ungrounded AC control circuits operating at a voltage less than the supply voltage
Blue - ungrounded DC control circuits
Yellow - ungrounded control circuits or other wiring, such
as for cabinet lighting, that remain energized when the main disconnect is in the "off" position
White or natural grey - grounded AC current-carrying control circuit conductor, regardless of voltage
White with blue stripe - grounded DC current-carrying
control circuit conductor
White with yellow stripe - grounded AC control circuit
current-carrying conductor that remains energized when the
main disconnect is in the "off" position

The UL508A standard does not apply to wiring outside the
industrial control panel.

Richard Gue
Controls Engineer
North Star Ice Equipment Corp.
Seattle, WA
(206) 763-7300 voice
(206) 763-7323 fax
 
B

Bob Peterson

There are various such standards. IEC uses one set of colors, NFPA79 uses another. Depends on what part of the world you are in.

Here in the US only certain colors are specified by the electrical code (NEC or NFPA70) (such as green or bare for ground and white or gray for neutral). Others are left to the imagination but in practice most of the time red or black is used for hot wires for 120V circuits, and usually black is used for 3 phase circuits with bands of colored tape to differeniate the phases.

Keep in mind that different standards might well apply to different pieces of your wiring, and that in some cases there is no applicable standard (for instance NFPA79 only applies to machine tools).
 
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Richard Benton

The color code that you are talking about is set up in the JIC electrical standards for machine tools and industrial equipment. The JIC is the Joint Industrial Council. YOU ARE 100% RIGHT!

The national electrial code does not address wire colors except to identify ground (green), grounded neutral (white), high voltage neutral (gray), and the highest voltage lead of a three phase delta four wire system (orange).

You need a copy of the JIC electrical standards. These standards, though outdated, have not been superseded by any other code or standard.
 
C

Chris Berhost

Please note that section 66.9 applies to industrial machinery such as:

Metalworking Machine Tools
Plastic Machinery, (injection molding, extrusion, blow molding, etc.)
Woodworking, Laminating and Sawmill machines
Assembly machines
Material handling machines and robots
Inspection and testing machines

They do not apply to general use industrial control panels.
 
I
I guess you are in the US. If you connected Active (hot) to a black conducter here in Australia you would lose your license... lol
 
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Reuben Gonzales

Hello, I am relocating to South Australia and I am in dire need of information concerning books, for the codes and other information that pertains to the testing that is involved in obtaining an electrical license. I will be hopefully be testing for an electrician special class license. I hope that you can help thanks.
 
JIC was rolled into NFPA 79 many years. New revisions of NFPA-79 should be reviewed for current specifications, however, most industrial equipment manufacturing companies and blue their customers have their own internal build specs that provide direction on what specifications are applicable.
 
J
2009 NFPA 79 Electrical Standard for Industrial Machinery dictates wiring colors for industrial machinery - go nfpa.org for ordering info

Black = AC power at line voltage

Red = AC power at less than line voltage

White; neutral Gray = AC Neutral conductor at less than line voltage

Blue = Ungrouded DC power

Blue/white stripe or white/blue stripe = DC grounded voltage

Orange or Yellow = excepted voltage that may be energized while the main disconnect is in the off position

Green; Green w/yellow stripe = equipment grounding conductor

Jim Everhart
Power Lab Controls
Welcome NC

RHEC Industrial Controls
Lexington NC
 
This is a topic which I am attempting to address with the NEC/NFPA/UL. An ABB 'White Paper', "NFPA79 and UL508A
Industrial Machinery Operating Handle Requirements a White Paper by ABB, Inc." published in April 2007 states:

[begin quote]
What is an Industrial Machine? According to NFPA79 and UL508A, the following types of machines are classified as Industrial Machinery:

a) Metalworking machine tools
b) Plastics machinery
c) Wood working machinery
d) Assembly machines
e) Material handling machines
f) Inspection and testing machines

What is not an Industrial Machine? The following types of machines are not classified as Industrial Machinery.

a) HVAC
b) Pumps
c) Fans
d) Wastewater treatment
e) Portable machines of any kind.

[end quote]

If it not classified as such, it is NOT covered by these codes/standards! As such, a control panel for an oil or gas SCADA/control panel or RTU is NOT associated with Industrial Machinery!

Since the original Instrumentation engineers and technicians usually had DC electronic backgrounds, 'Black' is always the DC return/ground wire.

In 2-wire transmitter cables, 'White' is usually associated with DC 'signals' or mA loops 'positive' wire. In a 3-wire transmitter, Red would be the DC positive power wire. OK, since transmitters are DC circuits, +24VDC usually comes out on the White wire to the transmitter and the controlled mA signal leaves/comes back on the Black wire eventually to the DC negative. This is traditionally through a 250 Ohm resistor located somewhere in the return path. Recently 'Electrical' engineers and AC electricians have been trying to design and install according to what they know - AC, which is different from DC and also NOT found in most existing instrumentation installations.

Bottom line is that this threads codes/standards are very EQUIPMENT specific. Industrial Instrumentation installations need to be specifically addressed by NFPA/NEC/UL. I will be making proposals/recommendations this year. In a separate thread I will start a discussion on the specific wording.
 
Kudos to Mr. Everhart. For those wishing exact references to NFPA 79, it can be found in Chapter 13.

13.2 Identification of conductors.

13.2.2.1 & 13.2.2.2 deal with Green and Yellow

13.2.3.1 deals with White and Gray

13.2.3.2 White/Blue and White/Orange

13.2.4.1 applies to the specific use of Orange

13.2.4.3 applies to the use of Black, Red and Blue.

Also, many thanks to Mathew for confirming the convention that is currently in use with current loop instrumentation circuits.

Tim Reese
Instructor
Everest College, San Bernardino, CA
 
> I have a Eng. that is tring to use color coding differnt to what I was always told to use as the standard. Can any one direct me to a book or web site with such coding or tell where to find it in the code book. Red is AC and Blue is DC. <

Doesnt it seem odd to anyone that we have written standards, codes, and the damn CFR, yet we cannot even decipher any of them enough to agree on what colors should be used?

This thread gives more credance to thoughts that much of the 'code' is driven and developed to fuel corporate interests associated with wiring devices. So go ahead and wave the code book in the air, stomp your feet some, quote chapter and verse with fire and brimstone.

Any written standards that are so vague and interpretive that leave room for smart folks like us to disagree are not effective and become relegated as a guide, not a regulation. Imagine trying to enforce these vague 'standards'!
 
K
Kudos to Mr. Richard Gue and Mr. Jim Everhart for getting it right.

I've designed and been inside a lot of industrial equipment over the last 20 years - including much in the list you describe as "not" industrial machines - never have I seen the wire color schedule that you describe.

Stick with NFPA 79 as described by the above 2 gentlemen and you can't go wrong.

Kurt Hanke, P.E.
Turbocraft, Inc.
Everett, WA
 
> 2009 NFPA 79 Electrical Standard for Industrial Machinery dictates wiring colors for industrial machinery - go nfpa.org for ordering info <

Is there a 2009 edition?

The 2007 edition states the color orange for excepted voltage that may be energized while the main disconnect is in the off position. The 2002 accepted orange or yellow, has this been changed back to either color or is orange the only accepted color?

Chris
 
You refereed to different color bands for different phases, Is there any code about how many bands per wire or spacing of those bands?

dlecheler [at] delkorsystems.com

>There are various such standards. IEC
>uses one set of colors, NFPA79 uses
>another. Depends on what part of the
>world you are in.
--- SNIP ---
 
I'm just wiring up a control circuit for a lighting control cabinet, the coils are 120VAC and the 2 wire control is 24VAC. Normally I wouldn't give it a second thought and just use red & white for both. But then I thought it would be helpful to make the 24VAC a different color to make it easy to trace inside the duct.....
Went looking and I can't find anything that CLEARLY states anything!
 
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