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Posted By: lynnbar how many circurts per neutral - 07/27/02 12:48 AM
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
Posted By: Roger Re: how many circurts per neutral - 07/27/02 01:19 AM
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
Posted By: lynnbar Re: how many circurts per neutral - 07/27/02 01:27 AM
roger,
thanks and youre not leaving me hanging there at all. ill take the time to check it out. Joe
Posted By: dana1028 Re: how many circurts per neutral - 07/27/02 02:05 AM
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!
Posted By: lynnbar Re: how many circurts per neutral - 07/27/02 02:10 AM
Dana,
that clears it up for me and i do see your point. Joe
Posted By: Bill Addiss Re: how many circurts per neutral - 07/27/02 02:20 AM
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
Posted By: lynnbar Re: how many circurts per neutral - 07/27/02 02:24 AM
bill,
thats where i seen this at on a 3 phase panel, joe
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