Motor Starter Wiring

A little off topic here but it fits. uncle harry, I enjoyed your comment about marking conductors with the color orange. This color by NEC identifies the conductor with the highest voltage in a 240V, 3PH, DELTA supply. High leg, wild leg, crazy leg are all terms I have heard used. Any way my wife and I frequently argue about the colors orange and red, each accusing the other of being color blind.

The only other place I remember red being mentioned is as the "B" phase conductor of a 208-120V, 3PH WYE supply. Although I have never seen it printed, I have notice the color code used in US industry is as follows.

Black Power
White Neutral
Gray "
Green Earth ground
Green w/ yellow tracer " "
Red 120vac control
Yellow 24vac "
Blue 24vdc "

Knowing this it is very handy when troubleshooting an unknown piece of equipment. If nothing else just so you do not blow your meter up by not having set to the correct scale.

Anybody else experience this?

I also also enjoyed how people call a certified, tested electrician and are dumbfounded when he does not have a machine he has never seen before repaired and up and running in five minutes or less. After all he is a professional isn't he?
 
In the US and Canada, for the most part circuits are marked according to voltage and phase.

120/208V Wye connected 3 phase
A phase- black
B phase- red
C phase- blue
Neutral- white

120/240V single phase
A phase- black
B phase- red
Neutral- white

120/240V Delta connected
A phase- black
B phase- orange (high leg)
C phase- blue
Neutral (if present) - white

277/480V Wye 3 phase
A phase- brown
B phase- orange
C phase- yellow
Neutral- natural gray

These color markings are traditional but not required by the electrical code except for the neutral colors which "Shall" follow the code colors noted above and may not be used otherwise except for very narrow exceptions. The code does mention the phase colors in a sub text, but does not mandate their use.

440V is supplied from a Delta connected transformer and is very uncommon these days unless you are in an industrial setting with very high motor loads. Even then it is uncommon. Unless you are a maintenance electrician in a plant, it would be unusual for most people to ever encounter 440V 3 phase or 440V/240V 3 phase. (open or closed delta connection)

In some areas, the 120/240V Delta connected supply may have the high leg on C phase, requiring the orange marking. This is dependent on the rules the utility uses and how they supply the incoming power in your area. In this case, B phase would be marked red.

Bob
 
BobSchu said:
440V is supplied from a Delta connected transformer and is very uncommon these days unless you are in an industrial setting with very high motor loads. Even then it is uncommon. Unless you are a maintenance electrician in a plant, it would be unusual for most people to ever encounter 440V 3 phase or 440V/240V 3 phase. (open or closed delta connection)
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However, in sloppy usage "440" is often used to mean "480 just as "110" is often used instead of "120".
 
rdhem2 said:
A little off topic here but it fits. uncle harry, I enjoyed your comment about marking conductors with the color orange. This color by NEC identifies the conductor with the highest voltage in a 240V, 3PH, DELTA supply. High leg, wild leg, crazy leg are all terms I have heard used. Any way my wife and I frequently argue about the colors orange and red, each accusing the other of being color blind.

The only other place I remember red being mentioned is as the "B" phase conductor of a 208-120V, 3PH WYE supply. Although I have never seen it printed, I have notice the color code used in US industry is as follows.

Black Power
White Neutral
Gray "
Green Earth ground
Green w/ yellow tracer " "
Red 120vac control
Yellow 24vac "
Blue 24vdc "

Knowing this it is very handy when troubleshooting an unknown piece of equipment. If nothing else just so you do not blow your meter up by not having set to the correct scale.

Anybody else experience this?

I also also enjoyed how people call a certified, tested electrician and are dumbfounded when he does not have a machine he has never seen before repaired and up and running in five minutes or less. After all he is a professional isn't he?
Click to expand...


Your color listing is correct according to NFPA 79 2012. They do specify black for all incoming power above 120 VAC. The old B O Y specification is now black for all 3 lines. They SHALL be labeled L1, L2 and L3 as well. I hope everyone understands that my submissions on this topic are intended for safety awareness (including awareness of meticulous inspectors authority).
 
John,
Your statement assumes that 440V and 480V are interchangable when connecting equipment. Not so in many cases. Many motors designed for 460/480V supply don't work well on a 440V supply.
Now, in slang usage 460 and 480 are discussed in the same vein, but not 440V. At least not by electricians who work around these voltages.

Bob
 
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BobSchu said:
Your statement assumes that 440V and 480V are interchangable when connecting equipment.
Click to expand...
No, I just noted that the terms "440" and "480" are often used as if they were interchangeable. I described the usage as sloppy.
 
uncle harry said:
Your color listing is correct according to NFPA 79 2012. They do specify black for all incoming power above 120 VAC. The old B O Y specification is now black for all 3 lines. They SHALL be labeled L1, L2 and L3 as well. I hope everyone understands that my submissions on this topic are intended for safety awareness (including awareness of meticulous inspectors authority).
Click to expand...

Perhaps in manufacturing wiring that may be true. However, in field wiring and industrial installations the Black, Red, Blue and BOY designations are alive and well. We still use this designation and in many cases in the buildings we have been constructing lately, phase tape markings are not allowed and we are required by specification to order color coded insulation on all of our wire jackets for feeders and branch circuits, regardless of size. Ordering everything from #12 THHN up to 750KCM wire in color coded jackets can get very expensive. Customers like Intel and various Data centers are willing to bear the cost to avoid any chance of a mistake being made which could cause disruptions in electrical service or damage to machines.

Bob
 
WOW!!!!! 500mcm in a nice orange or yellow for example, in a 40' length for example. Now that would indeed be an expensive proposition. Probably why most wire above #6 or #4 comes in any color you wish as long as it is black!!!!!! Not many contractors I know can afford to stock 1000' reels of large wire in even the basic colors. I have seen it but is not the norm.

Gentlemen--on the voltage designators, have we forgotton the 10% line variation allowed by code? Lets see, 480v- 10% = 432v. Hence covering the 440 nomenclature. In our area high voltage is sometimes a problem. The power company practice is to set the taps on the transformers up a notch or two when they expect to see large motor loads. 510v to 520v is not uncommon and is a little hard on small motors but does not seem to bother the larger units. Have had to have them come out and "lower" the voltage in a couple instantances to reduce motor failure.
 
The problem with motors isn't the allowable 10% voltage drop. Depending on the design of the motor, many motors don't operate well outside the voltage allowance the manufacturer recommends. This is quite often in the 5% range for very large motors and slightly more for smaller motors. If there is a problem with substantial voltage variations in some plants, a buck/boost transformer can be installed to stabilize the voltage. We do this quite often when a building has 208V 3 phase power and the motors on a machine or manufacturing line are supplied as 240V. A separate supply panel would be installed with a boosting transformer to bring the voltage in line with needed supply then the branch circuits would be supplied only by that panel, including the control power. Same type of thing can and will be done if a 440V motor would be run on a 480V supply, however 440V motors are so rare these days that this isn't really an issue in most instances. If you don't pay attention to these details you can get into all kind of power factor issues and excess billing issues in big industrial plants.

Yes, the wire with colored jackets can get very expensive. Last time I checked pricing (at least several years ago) on 500 KCM wire, it was running about $12 a foot in black, the upgrade for the colored jackets is around $1-$2 per foot. A couple weeks ago, we pulled in 12,000 feet of 4/0 colored jacket 120/208V (black, red, blue, white) feeders for 12 new panels in a data center. Hate to see the wire bill for that job.

I'm feeling a little foolish that we've kidnapped this topic from the original poster.

Bob
 
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