2016 Code Revision and Interpretation Committee Code Interpretation
(Last Updated: April 21, 2017)

In an effort to help the electrical industry make a smooth transition into the new Electrical Code and ensure the continuity in the performance of electrical work, the Department of Buildings will be posting code interpretations on its website. Listed below are new code-related questions and corresponding interpretations by the Code Committee. The users of this list should have available the 2008 edition of the NEC and the associated NYC Amendments to the 2008 NEC , as well as (Local Law 39/11) that went into effect on March 1, 2012.

To learn more about what each CHAPTER/topic is about, click on the chapter number. To find questions on the related topic, click on the topic or section Code.

CHAPTER 1: General (Section 110.1 to 110.79)
CHAPTER 2: Wiring and Protection (Code Section 200.1 to 285.28)
CHAPTER 3: Wiring Methods and Materials (Code Section 300.1 to 398-104)
CHAPTER 4: Equipment for General Use (Code Section 400.1 to 490.74)
CHAPTER 5: Special Occupancies (Code Section 500.1 to 590.7)
CHAPTER 6: Special Equipment (Code Section 600.1 to 695.14)
CHAPTER 7: Special Conditions (Code Section 700.1 to 770.182)
CHAPTER 8: Communications Systems (Code Section 800.1 to 830.179)
CHAPTER 9: Tables (Table 1 to 12(B))
Articles: A subdivision of a Chapter, comprised of a certain number of Sections
Administrative: General Requirements

All interpretations are based on the 1999 NEC and associated NY City amendments.*

Whenever there are a few sections referenced, the first one is the "lead section", and the rest are secondary sections. All the secondary sections are referenced with the purpose of offering additional clarifications.**


Chapter 1: General (Section 110.1 to 110.79)

Section 110.26(F)(1) - (2/3/2016)

Question is regarding Dedicated Electrical Space, sub-section 110.26(F)(1)(a), adding electrical equipment above or below existing equipment that either the existing or the new equipment will be within the dedicated electrical space.
Because the code mentions foreign systems (piping, ducts leak detection etc.) are not allowed and doesn't specifically mention whether other electrical equipment (panelboards, transformers, switches etc.) are or are not allowed in this space the following questions have arise.

Condition that raised this question is as follows: there is an existing transformer ceiling/wall mounted at a height of 9' to the bottom of the transformer.
1. Does the transformer require the dedicated space as per (F)(1)(a)?
2. Can the following electrical equipment some of which require dedicated elec space be installed under this transformer were the 6' dedicated space above will not be maintained.
   (a) A 6" deep panelboard that is not connected or part of the transformer?
   (b) A panelboard that is either connected to the line side or load side of the  transformer?
   (c) A Disconnect switch that is either connected to the line/load side or not part of transformer at all nor required as per the exception noted under (F) in the code?

1. No.
a. Yes, where the head room is maintained.
b. See (a).
c. See (a).

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CHAPTER 2: Wiring and Protection (Code Section 200.1 to 285.28)

Section 210.52(A) - (2/3/2016)

Section 210.52(A) outlined required receptacle spacing for dwelling unit such that no point measured horizontally along the floor line in any wall space is more than 6 ft from a receptacle outlet.  It also defined wall space in 210.52(A)(2) as any space 2 ft or more in width and unbroken along the floor line, space occupied by fixed panels in exterior walls, and space afforded by fixed room dividers. The NEC handbook includes the following in section 210.52(A) "The word usable does not appear at all in 210.52 as a condition for determining compliance with the receptacle spacing requirements. As an example, to correctly determine the dimension of the wall line in a room, the wall space behind the swing of a door is included in the measurement. This does not mean that the receptacle outlet has to be located in that space, only that the space has been included in the wall-line measurement."

  1. Does an opening in floor (doorways, fireplaces and similar openings) resets the receptacle placement requirement such that each unbroken wall space is considered as an individual separated wall spaces and that receptacle is needed in each individual separated wall space?
  2. A wall is separated by (2) doors such that the wall space between the doors is 2'-0", does this section of the wall required dedicated receptacle?  Does a receptacle 1'-0" from the edge of the other side of either door meets the intent of the code such that any point on the 2'-0" wall is no greater than 6'-0" along the floor line from a receptacle?
  3. A wall include a bump out in the center, the bump out is measured along the floor line such that is it 1'-0" depth and 2'-0" width.  The walls to the left and right of the bump out are 4'-6" each.  Is 1'-0" depth floor lines required in the wall space calculation as it is less than 2'-0"?
  4. A receptacle is place 1'-0" away from the handle side of the door opening.  The wall space for the wall behind the door swing is 2'-0".  Is a receptacle needed on the 2'-0" wall? 


  1. Yes.
  2. Yes. This is a separate wall space and requires a receptacle. No, a receptacle that is 1'-0" from the edge of the other side of either door doesn’t meet the code intent.
  3. Yes.
  4. Yes, if the wall space in question is a separate wall space.           


Section 210.52(B) - (2/3/2016)

We have an existing multifamily building constructed around 1970 with only (1) one appliance 20A branch circuit for the kitchen countertop receptacles in each dwelling unit.  
We are replacing the kitchen cabinets, installing one new outlet for the gas stove and replacing the existing (Federal pacific) apartment panels.  The existing apartment feeders will not be upgraded. Based on the aforementioned scope of work:  

  1. Is a new 120vac 20A appliance branch circuit required in the kitchen?
  2. Are new outlets required to be installed to serve existing countertop to meet current code standards?
  3. Can the existing appliance branch circuit be extended to serve new gas stove receptacle?
  4. If the answer to question #3 is NO, can the existing raceway for the existing appliance branch circuit be used to run new 20A branch circuit to serve new gas stove outlet?

  1. No, if only the kitchen cabinet being replaced in-kind (no reconfiguration of kitchen layout).
  2. See answer to No. 1
  3. Yes.
  4. N/A.          


Section 210.52(H) - (2/3/2016)

Within the typical bedrooms, the entrance of the bedroom has a foyer/hallway 3'-6" wide of varying lengths. Is this space considered a "hallway" and does section 210.52(H) apply?

This space is part of the bedroom, and section 210.52(H) is not applicable.

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Section 250.21(A)(2) - (2/3/2016)

The violation we have received states that our motor control isolation transformers are a separately derived system. NEC 2008 ARTICLE 100 - definitions - defines a separately derived system as "A premise wiring system whose power is derived from a source of electric energy or equipment other than a service". ARTICLE 100 further defines "premise wiring" with the following exceptions, "Such wiring does not include wiring internal to Appliances, Luminaires, Motors, Controllers, Motor Control Centers & Similar Equipment". Based on the above definitions, our transformer, because it is an integral part of our motor control center & motor controller, is not a separately derived system (See Figure 620.13 from the CODE), which shows, in this one line diagram, that the transformer is located after the disconnect & short circuit protection and therefore a part of our control center/motor controller.

Section 250.21(A)(2); “separately derived systems used exclusively for rectifiers that supply only adjustable – speed drives” do not require grounding. In the case of elevator drive systems, the transformer secondary is directly wired to the industrial drive that controls the speed of the elevator. In addition, 250.21 A (3), also exempts separately drive systems supplied by transformers if conditions (a),(b),(c) are met. In the case of elevators it is our opinion these three conditions are met. 

Subsection 250.21(A)(2) permits a separately derived systems used exclusively for rectifier that supply adjustable –speed drives. Section 250.30 is not applicable.


Section 250.52 and 250.53 - (2/3/2016)

When an underground water pipe is used as the grounding electrode, it needs to be supplemented by an electrode listed in 250.52(a)(2) through (a)(8). This eliminates the possibility of using another underground water pipe as the supplemental grounding electrode. In the past we were told in the field that the use of the sprinkler main coming into the building, when entering as separate service, was acceptable as the supplemental since 250.52(a)(8) allows "other local metal underground systems or structures".
Please confirm if the sprinkler main, when entering the building as a separate service, is acceptable as a supplemental grounding electrode.

Sprinkler water supply pipe complying with this article is acceptable, unless such metal pipe is provided with nonconductive protective material or layer. Note; removing such protective material to make contact is not allowed.


CHAPTER 3: Wiring Methods and Materials (Code Section 300.1 to 398-104)

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CHAPTER 4: Equipment for General Use (Code Section 400.1 to 490.74)

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CHAPTER 5: Special Occupancies (Code Section 500.1 to 590.7)

Section 517.13 - (2/3/2016)

Is the provision of section 517.13 required in a veterinarian hospital?

No. Article 517 is for facilities that treats human. 

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Section 517.18(B) - (2/3/2016)

Are Hospital Grade Receptacles required in a dental Facility?

No; unless they are required by dental equipment manufacturers.

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CHAPTER 6: Special Equipment (Code Section 600.1 to 695.14)

Section 695.5 - (2/3/2016)

Our question pertains to using transformers to utilize 480V riser to feed 208V Fire Pumps (see sketch). The Electrical Engineer has asked us to look into taking the 208V feed for the Fire Pumps on the roof and use a transformer in the service room to step up to 480V, then use a transformer at the Dire Pump, before the controller to step back down to 208V. 695.5(A) states that secondary disconnecting and over-current is not permitted.

(A) Is the over-current device on the primary side of the second transformer considered also on the secondary side of the first transformer?
(B) Is this installation acceptable.

(A) Additional OCPD shall not be permitted to be installed in a fire pump circuit; other than the fire pump service switch.
(B) No. Use of transformers for the reason described in your inquiry and a remote service switch is not permitted under current NYC electrical code.                

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CHAPTER 7: Special Conditions (Code Section 700.1 to 770.182)

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CHAPTER 8: Communications Systems (Code Section 800.1 to 830.179)    

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CHAPTER 9: Tables (Table 1 to 12(B))

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ADMINISTRATIVE: General Requirements 


Copies of the NYC 2011 Electrical Code  (only the amendments to the NEC 2008 Electrical Code) and the New York City Electrical Code (the amendments and the NEC 2008 Electrical Code) can be purchased at the CityStore.


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