Wiring Color question

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  #1  
Old 06-29-06, 06:01 PM
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Wiring Color question

Just wondering if there was a special electrical color code

I always thought white was neutral and black was hot, I went looking for some wire at home depot and they sell yellow, brown, red, green, purple, orange and grey wire.

Does each color have its own purpose ?
 
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Old 06-29-06, 06:11 PM
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colors

green = ground white = neutral. All other colors are used for hots. In pipe or raceway with multiple lines (feeds) color coding is a way to differentiate hot circuits. color also plays a factor in higher voltages.
 
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Old 06-29-06, 06:18 PM
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Originally Posted by sbrock
Just wondering if there was a special electrical color code

I always thought white was neutral and black was hot, I went looking for some wire at home depot and they sell yellow, brown, red, green, purple, orange and grey wire.

Does each color have its own purpose ?
orange: "high leg" of a 4 wire delta with a center tapped phase

grounded conductor (also known as "neutral" although sometimes a misnomer)white and gray or 3 continous white stripes on other than green ; white or gray with stripes is acceptable (by choice, no requirements here)

itsunclebill also brought something to mind. Gray is often (but not required) used as the neut in 277v systems.

green or green with yellow stripes: equipment grounding conductor

light blue: intrinsically safe system conductor (permitted, not required)

the other colors, while not required are often use to identify different voltage systems and even phases of those systems;

black, red, blue are often used for 120/208/240 systems with black being "A" phase, red "B" phase and blue "C" phase.

Brown orange and yellow are often used for 277/480 volt systems with brown as "A" phase , orange as "B" phase, and yellow as "C" phase.

The high leg is generally put in the "B" phase position (unless passing through a meter in Elkhart, Indiana, then it has to be "C" phase. I don't know if this extends to all AEP sytems or not.

In control systems, red is often the color of choice with white for neutral.

DC systems often use red (+) and black (-) but I think blue gets tossed in there somewhere sometimes as well. I don;t do much DC stuff.

Some of the guys I work with like to use purple for travellers of a 3 way switch.
 

Last edited by nap; 06-29-06 at 06:50 PM.
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Old 06-29-06, 06:21 PM
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Gray is also used as a neutral, commonly found in industrial situations where several different voltage systems are in use, but no rule prohibits its use as a neutral in residential use.

Some other uses specify specific colors of wire but you're not likely to find these in a DIY project so within the confines of the restricted use of green, white, and gray, anything goes.
 
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Old 06-29-06, 10:43 PM
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green/bare = ground
white/grey = neutral
orange is reserved as the high leg ONLY when you have a grounded delta 3-phase. It may be used as any hot in any other system.

I like to use the colors. If I'm using conduit, I'll take full advantage of colors. Travellers, switch legs, phases; there are lots of reasons to use lots of colors.

But when running lots of MC or NM, you're going to do a lot of black and little red and not much more, just 'cuz that's how they make it.
 
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Old 06-30-06, 04:33 AM
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You should never assume that a white wire is a neutral and a black wire is hot.

There are two reasons I say this.

First, in certain situations a white wire is allowed to be hot. With normal household wiring using NM cable, a white wire is allowed to be re-identified and be a hot wire. This is typically done with switch loops.

Second, unfortunately there are some homeowners who do their own electrical work who really shouldn't. They get confused between AC and DC and sometimes make a black wire the neutral, or they just don't think it matters and use whichever wire they grab first for the next item to be connected.

Bottom line.

Never work on a circuit hot, even if you wired it yourself and know which wire is which.

Never assume that any wire is a neutral, a ground or a hot simply based on color alone.

Whenever you do any wiring, use the proper color wire, or when appropriate, re-identify the white conductor of a cable as hot. Use the right color wire even it means going back to the store and buying more wire.
 
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Old 06-30-06, 10:11 AM
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Originally Posted by racraft
First, in certain situations a white wire is allowed to be hot. With normal household wiring using NM cable, a white wire is allowed to be re-identified and be a hot wire. This is typically done with switch loops.
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I understand in such cases that the white wire is to be marked. Is this done by adding lines with a permanent marker?

DWC
 
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Old 06-30-06, 10:14 AM
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A white wire can be re-identified with either colored tape or with a permanent marker.

Use black, blue, red or any other color allowed for a hot wire.
 
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Old 06-30-06, 03:12 PM
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[QUOTE=MAC702]
orange is reserved as the high leg ONLY when you have a grounded delta 3-phase. It may be used as any hot in any other system.
QUOTE]


This is being picky but it is not just any grounded delta, it is for a center of phase grounded delta. A corner grounded delta will not give you a "high leg". It will actually give you a "0" voltage leg.

Also, the marking with orange is required only where there is a connection made to that phase
 
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Old 06-30-06, 10:05 PM
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Electricity is one area where being picky is being proper. Thanks for the correction. I was typing too fast and didn't bother to specify.

Originally Posted by nap
Originally Posted by MAC702
orange is reserved as the high leg ONLY when you have a grounded delta 3-phase. It may be used as any hot in any other system.

This is being picky but it is not just any grounded delta, it is for a center of phase grounded delta. A corner grounded delta will not give you a "high leg". It will actually give you a "0" voltage leg.
 
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