There are literally hundreds of code changes each time a new code book is released. Most are just new ways to say the same thing, hopefully making it clearer to understand the intent. Some, however, are adopted to improve the installation of electrical systems. I touched on some during an earlier post and I would like to note a few more here. I'll try to cover the new additions rather than just new wording of existing text.
200.4 Neutral conductors shall not be used for more than one branch circuit, for more than one multiwire branch circuit, or for more than one set of ungrounded feeder conductors unless specifically permitted elsewhere in this code.
So you cannot upsize the neutral conductor to a #8 to use with 6 circuits on a three phase system. You cannot upsize the neutral for a single run in a parallel feeder.
210.52 (I) Foyers that are not part of a hallway in accordance with 210.52 (H) and that have an area greater than 60 ft2 shall have a receptacle(s) located in each wall space 3 ft or more in width and unbroken by doorways, floor to ceiling windows, and similar openings.
This just clarifies a once gray area.
225.70 Substations - Consisting of 225.70 (A)(1)→(5) - An entirely new section devoted to substations concerning signage, disconnecting power before replacing fuses, and backfeed issues.
230.24 (E) Clearances from communications wire and cables shall be in accordance with 800.44(A)(4).
This just reminds everyone there is another section of the code dealing with communications wiring that was often overlooked.
230.44 Cable tray systems shall be permitted to support service entrance conductors. Cable trays used to support service entrance conductors shall contain only service entrance conductors and shall be limited to the following methods:
(1) Type SE cable
(2) Type MC cable
(3) Type MI cable
(4) Type IGS cable
(5) Single thermoplastic insulated conductors 1/0 and larger with CT rating.
They just clarified which service entrance conductors were acceptable for use in cable trays.
250.2 Bonding Jumper, Supply Side - A conductor installed on the supply side of a service or within a service equipment enclosure(s), or for a separately derived system, that ensures the required electrical connectivity between metal parts required to be electrically connected.
More clarification of what is actually intended.
250.24 (C)(3) Moved to 250.24 (C)(4). 250.24 (C)(3) now reads:
Delta Connected Service - The grounded conductor of a 3 phase delta service shall have an ampacity not less than that of the ungrounded conductors.
This means no derating for neutral loads on feeders for delta connected services.
250.30 received a large makeover. It spells out new requirements based on the clarification of the supply side bonding jumper definition, and rearranged a bit to walk you through the requirements in a more orderly fashion. It is a rather large section so I didn't quote it.
250.32 (B)(2) Supplied by separately derived systems
(a) With overcurrent protection, If overcurrent protection is provided where the conductors originate, the installation shall comply with 250.32 (B)(1).
(b) Without overcurrent protection, If overcurrent protection is not provided where the conductors originate, the installation shall comply with 250.30 (A). If installed, the supply-side bonding jumper shall be connected to the building or structure disconnecting means and to the grounding electrode.
This section points you back to section 250.30 if you have no overcurrent protection on the conductors of a separately derived system. This assures a more effective fault current path and operation of OCD's further upline.
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