Rule of thumb on wiring

[stickbender]

I'm In the middle of something I know nothing about but do need a answer. I have two electrical contractors tell me the rule of thumb for wiring 3 phase is BOY (brown, orange, yellow) and one says it definately should be BYO(brown, yellow, orange)

Can someone direct me in the right direction???????

 

[69boss302]

Re: Rule of thumb on wiring

Depends on Voltage. Rule of thumb 120V Black, White Red. Higher Voltage 480 and up, Brown Orange Yellow.

There is nothing in the NEC that designates this, as you can probably see in other threads.

 

[tom baker]

Re: Rule of thumb on wiring

If you have two different nonimal voltage systems, then the identification used must be posted, the colors can be purple, pink and blue if you want.
See 2005 NEC 210.5

 

[69boss302]

Re: Rule of thumb on wiring

Yes you can use any color you want. But there is an industrial rule of thumb for three phase as I said above.

Be very careful though. The "rule of thumb" Not NEC Code, is Black-White-Red for three phase AC. ****White is reserved for grounded conductor in the NEC**** I am used to all wires black anyway for three phase and designate with tap. Don't pull a white conductor for ungrounded (hot) phase lead.

OK now you can all jump on me and tell me how bad I am at code. That's what I've told you.

 

[jman34]

Re: Rule of thumb on wiring

Boss,

For 120/240V the 3 phase colors should be Black, Red, Blue and then White for the grounded conductor.
For 277/480V the 3 phase colors should be Brown, Orange, Yellow, and then Grey for the grounded conductor.
This is the "rule of thumb" I have always used and have saw it like this in 95% of the places I have worked in. Might be different in different parts of the country.

Jerry

 

[69boss302]

Re: Rule of thumb on wiring

Old Navy standard, (Bubblehead at that ). There are no grounded conductors on board ship so no arguments. Do have green EGC though.

Found that this held true in most industry, not to many industrial three phase 120 V applications in industry though. But the B, O, Y, has been the same.

 

[charlie]

Re: Rule of thumb on wiring

OK Boss, what is a Bubblehead?

 

[69boss302]

Re: Rule of thumb on wiring

Bubblehead=Submariner. As opposed to Skimmer, Target, or for you land lubbers, Surface Ship Sailor. However I did get both SS and SW quals.

 

[charlie]

Re: Rule of thumb on wiring

I am definitely a land lubber. For what it is worth, thank you for your service. I, for one, appreciate everyone who has served our country.

 

[rich14304]

Re: Rule of thumb on wiring

Hope this helps for Phase Arrangements.

Although the NEC no longer requires color coding usually Phase A is marked Black, Phase B Red and Phase C Blue for Voltages 600V or Less.

For OVER 600 volts the BOY method is used Brown for Phase A, Orange for Phase B and Yellow for Phase C.

The only other thing I can add is when a three phase Delta-connected system is used and a midpoint neutral tap of one of the transformers is brought along with the phase conductors the voltage to the grounded neutral will be higher than that of the other two phases to ground.

The HIGHER voltage to ground MUST be marked or tagged with ORANGE and this higher voltage to ground MUST be Phase B.

Removed the e-mail address. Please use the PM system to exchange personal information and e-mail addresses. Thanks, Charlie

[ April 10, 2005, 07:59 PM: Message edited by: charlie ]

 

[roger]

Re: Rule of thumb on wiring

Rich, BOY is typically used for 277y/480 v.

The high leg of a delta doesn't necessarily have to be orange, read 215.8 and 230.56 and take note of the wording "orange in color, or by tagging or other effective means.

Roger

 

[rich14304]

Re: Rule of thumb on wiring

Rodger,
Thank you for reminding me to be more precise in my replies. Please accept my apologies for any misrepresentations threw negligent scripting.

Designing Electrical Systems 384-3(f) pg46 does state that for Phase arrangements BOY method is used for over 600 volts.

If the methodology has changed regarding the application of BOY, I was simply uninformed and appreciate the update.

 

[safeguy]

Re: Rule of thumb on wiring

So...Now that we're on three phase JARGON...What about when changing motors rotation. Should one swap Phases A and B, A and C, B and C...Or it doesn't matter....?
Why one of those phase swapping, and which one, should not be used...? Or so I've heard...! Any one..?

Thanks a lot.

 

[69boss302]

Re: Rule of thumb on wiring

Safeguy; Doesn't matter, swap any two. This reversed the direction of the stator field that is generated. The direction of the flux around the wire is directly related to the direction of the current in it. I believe (old age makes me forgetful) it's the right hand rule. If you place your thumb on the wire in the direction the current is going and wrap your fingers around the conductor, the direction your fingers go indicate the direction of the flux produced.

That's the very basic. All these lines of flux produce the overall stator flux and if you were to look at a three phase current graph and plot the times and directions of current, look at each coil then you would see how the rotation changes.

Oh also again another rule of thumb, I think it's the right hand again for a coil. If you wrap your fingers around the coil in the direction of the current in the coil, then your thumb will point towards the generated North Pole.

 

[celtic]

Re: Rule of thumb on wiring

It's the left hand rule/method, Grandpa...LOL

 

[al hildenbrand]

Re: Rule of thumb on wiring

IMO, left or right is based on whether the current flow is defined as the direction the electrons flow or the direction the positive charge flows.

Either is correct, depending upon the current convention.

"Conventional" current is defined as going from the + source terminal to the - source terminal. This is the "positive charge" current.

"Electron flow" is in the opposite direction.

 

[sirdle]

Re: Rule of thumb on wiring

BTW, whether it is the right-hand rule or the left-hand rule depends on what convention you use for current direction.

Older texts and engineering and physics texts usually identify the current direction as the direction that imaginary positive charges would flow through the circuit. This simplifies the advanced math used in circuit analysis.

Newer texts and texts written for electricians often define current as the direction that electrons flow through the circuit.

Edit: (sorry, didn't see Al's post when I wrote this.)

[ April 22, 2005, 11:43 AM: Message edited by: sirdle ]