wiring of lighting fixtures

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bench892

Member
What is the proper wiring of lighting fixtures? I am using a three phase power source, the layout shows three lighting branch circuits using a common neutral. Is this according to code? Or should we run separate neutral wires for each branch circuit?

[ August 13, 2003, 04:57 PM: Message edited by: bench892 ]
 
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bench892

Member
Re: wiring of lighting fixtures

Should the feeder wires come from the same phase or should it be coming from different phases?
 
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gregoryelectricinc

Senior Member
Re: wiring of lighting fixtures

Bench, Are you an electrician? What the plan is showing is what we typically refer to as a "round robin". The code book calls them multi-wire branch circuits. To answer your questions, the nuetral conductor is sized the same as the ungrounded conductor and the individual branch circuits MUST originate from different phases of the panel.
 
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bench892

Member
Re: wiring of lighting fixtures

Gregory, I'm not yet an electrician. I am still studying to be one.

So, based on your reply no two phases should be in the same raceway with a common neutral.

If the neutral is the same size as the three feeder wires, will it result to the overloading of the neutral. For additional info the lighting loads is mostly fluorescent lighting fixtures w/ electronic ballast.
 
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gregoryelectricinc

Senior Member
Re: wiring of lighting fixtures

The nuetral currents will cancel each other out resulting a N current of the imbalance of the loads only.
Example:
A phase 12 amps
B Phase 12 amps
C Phase 8 amps

Nuetral current = 4 amps

Good Luck in your studys
 
roger

roger

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Staff member
Location
Fl
Occupation
Retired Electrician
Re: wiring of lighting fixtures

Bench,
So, based on your reply no two phases should be in the same raceway with a common neutral.
Click to expand...
this not what Gregory is saying at all.

You should go to your instructor for a face to face explanation.

Roger

[ July 15, 2003, 01:22 PM: Message edited by: roger ]
 
charlie

charlie

Senior Member
Location
Indianapolis
Re: wiring of lighting fixtures

Originally posted by Bench892:
For additional info the lighting loads is mostly fluorescent lighting fixtures w/ electronic ballast.
Click to expand...
You may also have an additional problem with harmonics. With electronic ballasts it is possible to have a little more than twice the phase current on the neutral. :(
 
charlie

charlie

Senior Member
Location
Indianapolis
Re: wiring of lighting fixtures

Originally posted by bench892:
Gregory, I'm not yet an electrician. I am still studying to be one.
Click to expand...
I am wondering why you don't change your profile to be truthful and not call yourself a consultant. Additionally, why are you posting the same question in more than one place? :confused:
 
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bench892

Member
Re: wiring of lighting fixtures

Regarding the posting of the question, I made an error, I tried to delete it but I was not authorized to do so. I felt that the best forum for my question is on the NEC portion so I re-posted it.

[ July 15, 2003, 02:57 PM: Message edited by: bench892 ]
 
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hbendillo

Senior Member
Location
South carolina
Re: wiring of lighting fixtures

Is this actual work you are doing or a problem you are working out? Do you have someone supervising you? Most states require that a licensed electrician supervise work. In some cases that person does not always have to be present but at least you would have him available to answer questions and inspect the work. I appreciate you asking the question to get it right but try to run things by your supervisor because he is ultimately going to be responsible.
 
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