The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Industrail Control Panel bonding per 409.108
by sparkyinak
Yesterday at 06:29 PM
Calling all Non-US members!! (Non-US only)
by aussie240
12/07/16 02:39 AM
Photo Upload Tutorial
by DanK
12/06/16 11:35 PM
Sprinklered equipment 26-008
by bigpapa
12/02/16 04:24 PM
On Delay Relay with Auto Reset
by Potseal
12/01/16 09:59 AM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 13
HotLine1 10
sparkyinak 9
Texas_Ranger 8
Potseal 6
Who's Online
1 registered (Tjia1981), 219 Guests and 5 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#92345 - 03/14/05 11:58 AM Neutral Counted As Current Carrying
mustangelectric Offline
Member

Registered: 02/08/04
Posts: 496
Loc: Bentonville, AR
If a circuit supplies a fluorescent, mercury or metal halide do the neutrals still have to be counted as current carrying? This neutral will carry a third harmonic.

Thanks for any replies

Greg
_________________________
Electricity has no respect for ignorance!

Top
2014 / 2011 NEC & Related Books and Study Guides
#92346 - 03/14/05 12:29 PM Re: Neutral Counted As Current Carrying
Ryan_J Offline
Moderator

Registered: 08/19/03
Posts: 1355
Loc: West Jordan, Utah, USA
Yes, any non-linear(harmonic) load creates a current carrying nuetral.
_________________________
Ryan Jackson,
Salt Lake City

Top
#92347 - 03/14/05 12:35 PM Re: Neutral Counted As Current Carrying
resqcapt19 Offline
Member

Registered: 11/10/00
Posts: 2209
Loc: IL
Only on 3 phase systems.
Don
_________________________
Don(resqcapt19)

Top
#92348 - 03/14/05 02:09 PM Re: Neutral Counted As Current Carrying
Joe Tedesco Offline
Member

Registered: 10/07/00
Posts: 3325
Loc: Boston, Massachusetts USA
... and only when that nonlinear load is the major portion (over 50%) ....

See the 2005 NEC .....

Nonlinear Load. A load where the wave shape of the steady-state current does not follow the wave shape of the applied voltage.

Article 310

(c) On a 4-wire, 3-phase wye circuit where the major portion of the load consists of nonlinear loads, harmonic currents are present in the neutral conductor; the neutral shall therefore be considered a current-carrying conductor.
FPN: Electronic equipment, electronic/electric-discharge lighting, adjustable-speed drive systems, and similar equipment may be nonlinear loads.
_________________________
Joe Tedesco, NEC Consultant

Top
#92349 - 03/14/05 07:58 PM Re: Neutral Counted As Current Carrying
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9045
Loc: Estero,Fl,usa
You can still induce out of phase currents in a single phase neutral (multiwire circuit) but you won't get the overload effect you get in 3 phase. It can still make measurememnts not balance if your meter isn't true RMS.
_________________________
Greg Fretwell

Top



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals