American phase colouring convention 2

[kvkev]

Can anyone help with the american cable core colouring system. In a single phase system I have black, white and green. Is white the conventional live core ?
In a three phase and earth (delta) system I have red, white, black, (and green). What is the conventional rotation ?
e.g. in U.K it is red, yellow, and blue rotation.
If it was a 5 core (star) american system what are the identification colours.

Thanks
kvkev

 

[dpc]

I can answer part of your question:

For single phase circuits:

Black - HOT!
White - Neutral (Current-carrying conductor)
Green - Earth (Safety Ground)

White MUST be a neutral conductor per U.S. code
Green MUST always, always, always be ground wire per US Code.

For three-phase, there is no single standard color coding convention, except that you can't use white or green for a phase conductor (see above). Commonly used, but by no means a standard:

A - Black, B - Red, C - Blue
A - Brown, B - Orange, C - Yellow

The NEC also requires that 3-phase, 4-wire delta system (wild leg) have the wild leg phase colored ORANGE.

As to the "5 core" system, I'm not sure what that is.

 

[jghrist]

As noted by dpc, there is no standard for the phase colors in the US, let alone for the phase rotation, except for the prohibition against using white or green for phases.

There are two conventions for coloring wires in multi-conductor control cable. K-1 uses Black, White, Red, Green, Orange for a 5/c cable. K-2 uses Black, Red, Blue, Orange, Yellow. A 4/c cable uses the first four of these colors. Note that if you use convention K-2 cables for a three phase ac circuit, you don't have any white or green conductors. They can be tagged white or green at the terminations.

Many US utilities use Red, Yellow, Blue for single conductor phase identification, either with colored insulation or with tape.

Also note that we color our insulation instead of colouring it.

 

[Lewish]

What dpc said is all well and good, but some motor manufacturers don't adhere to it. You will find cables sticking out of their motors, as shipped from the factory, with white, black and green for the 3 phase wires.
But, if you are wiring a building, you better not do or the inspector will get you.

 

[BJC]

My experience is that:
Single phase circuits Black, White, Red L1,N, L2.
208/120V 3phase systems Black, Red, Blue, White A,B,C,N
480,277 V 3 phase systems Brown, Orange, Wellow, White( or Gray) A,B,C, N
The above is usually in commercial buildings where circuits are run in conduit and there may be wires hanging around with nothing but color for identification. The white or gray for neutral is I believe for cases where some fool runs both systems in the same raceway ( stupid but still done). The NEC requires the method be identified by signs on the panels. Still can be confusing, The best method is to have completely seperate raceway systems.
In utility applications ( power plants) and industrial applications the Black Red Blue color scheme is used commonly for 480/277V systems because it's a standard used in most multiconductor power cables.( ICEA Method 1)

 

[dpc]

Lewish makes a good point - the NEC only applies to premises wiring and not manufactured equipment. Although I doubt you'll find a green phase lead on a UL-listed motor.

 

[stevenal]

Americans don't have a colouring system. It's a coloring system here.

 

[kvkev]

Thanks everyone for the help. ( And the English lesson ) I can get my machines up and going now.

kvkev

 

[jbartos]

Suggestion: Visit

http://www.okonite.com/glossary.html

for more info

 

[busbar]

A further wrench in the gears:

http://www.cp.berkeley.edu/CDS_ucb/Div-16-2.html

§B.2.a.