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Joined: Jul 2002
Posts: 6
L
lynnbar Offline OP
Junior Member
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

Joined: May 2002
Posts: 1,716
R
Member
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

Joined: Jul 2002
Posts: 6
L
lynnbar Offline OP
Junior Member
roger,
thanks and youre not leaving me hanging there at all. ill take the time to check it out. Joe

Joined: Jan 2002
Posts: 163
D
Member
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!

Joined: Jul 2002
Posts: 6
L
lynnbar Offline OP
Junior Member
Dana,
that clears it up for me and i do see your point. Joe

Joined: Oct 2000
Posts: 4,080
Likes: 3
Member
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


Bill
Joined: Jul 2002
Posts: 6
L
lynnbar Offline OP
Junior Member
bill,
thats where i seen this at on a 3 phase panel, joe


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