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

Topic Options
Rate This Topic
#11921 - 07/26/02 05:48 PM how many circurts per neutral
lynnbar Offline
Junior Member
Registered: 07/26/02
Posts: 6
Loc: volga west virgina usa
just a dumb little question, ive seen this in a few boxs where they will use one neutral per three circurts, I myself like to give each circurt its own neutral.
is this becoming or has been a way to save money. just wondering is all thanks joe
Top
Work Gear for Electricians and the Trades
#11922 - 07/26/02 06:19 PM Re: how many circurts per neutral
Roger Offline
Member
Registered: 05/18/02
Posts: 1716
Loc: N.C.
Joe, I'm going to assume you are new into the trade. Please research branch circuit multiwire covered in the NEC Article 100.
as well as 300 and 310 and more.

I don't mean to leave you hanging, but if you read these articles it will help more than an answer on the internet.

Remember that a grounded conductor per one circuit is not a neutral in reality.

Roger
Top
#11923 - 07/26/02 06:27 PM Re: how many circurts per neutral
lynnbar Offline
Junior Member
Registered: 07/26/02
Posts: 6
Loc: volga west virgina usa
roger,
thanks and youre not leaving me hanging there at all. ill take the time to check it out. Joe
Top
#11924 - 07/26/02 07:05 PM Re: how many circurts per neutral
dana1028 Offline
Member
Registered: 01/09/02
Posts: 163
Loc: San Carlos, CA
Joe -

You asked if 'this' was a way of saving money....I'm sure that may play some part with this practice, but if you check out 310-15(b)(4)(a) [1999] this will give a good reason for using the shared neutral. Example: if you tried to pull 6 circuits in a conduit using your one-neutral-per-circuit method you would have to derate the conductors 50% (Table 310-15b2a)... #12 THHN would only be rated for a 15A circuit ... using the shared neutral process you only derate 20%....in fact, you could get nine 20A circuits (using #12THHN) in one conduit (shared neutral method)vs. only 4 circuits using your method....god I hope I didn't blow my arithmetic!
Top
#11925 - 07/26/02 07:10 PM Re: how many circurts per neutral
lynnbar Offline
Junior Member
Registered: 07/26/02
Posts: 6
Loc: volga west virgina usa
Dana,
that clears it up for me and i do see your point. Joe
Top
#11926 - 07/26/02 07:20 PM Re: how many circurts per neutral
Bill Addiss Offline
Member
Registered: 10/07/00
Posts: 3875
Loc: NY, USA
lynnbar,

You have to realize that this is only an option under certain circumstances, it cannot always be done. For what you describe it would have to be a Three-Phase system and all on different 'phases' or 'legs'.

Bill
Top
#11927 - 07/26/02 07:24 PM Re: how many circurts per neutral
lynnbar Offline
Junior Member
Registered: 07/26/02
Posts: 6
Loc: volga west virgina usa
bill,
thats where i seen this at on a 3 phase panel, joe
Top

Member Spotlight
Member Since: 05/03/03
Posts: 1137
New in the Gallery:
SE cable question
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box


Who's Online
1 registered (HotLine1), 81 Guests and 8 Spiders online.
Key: Admin, Global Mod, Mod
 
New in the Gallery:
SE cable question
 
Top Posters (30 Days)
Admin 47
HotLine1 43
gfretwell 19
Ruben Rocha 12
Trumpy 9
 
Newest Members
KrmtFrg, Stack, Scotto, Freecrowder, clee512

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