2006 Code Revision And Interpretation Committee Code Interpretation (Last Updated: January 19, 2007)

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 2002 edition of the NEC and the associated NYC Amendments to the 2002 NEC, as well as (Local Law 81/03) that went into effect on January 1, 2004.

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.

Click a topic, or press the enter key on a topic, to reveal its answer.

Chapter 2: Wiring and Protection (Code Section 200-1 to 280-25)

Section 210.52 & 210.70(A)(3) - (3/8/2006)

  1. An existing office building is being converted to residential use. Each new apartment will include non-habitable spaces such as a home office and a storage room.
      1. Do these spaces have to comply with Section 210.52 when it comes to receptacle placement?
        Section 210.52(A) applies.

      1. Currently, one switched receptacle is provided in the storage room for lighting purposes.
          1. Is this in compliance with Section 210.70(A)(3)?

        1. Is a dedicated lighting outlet required in this area?
          Does not apply for the described design.

    1. Currently, one switched receptacle, one un-switched receptacle and one data outlet are provided in the home office.
        1. Is this in compliance with Section 210.70(A)(3)?

      1. Is a dedicated lighting outlet required in this area?
        Does not apply for the described design.

Section 210.52(D) - (3/8/2006)

  1. With regard to the requirements of Section 210.52(D), is it permissible to mount a bathroom receptacle in the back of the medicine cabinet which is not adjacent to the basin or to the basin countertop?
    The described receptacle does not satisfy the requirements of Section 210.52(D).

Article 220 - (2/8/2006)

    1. In an apartment building, each apartment is equipped with electric cooking and electric heat pumps. Should the feeder between the meter bank and the apartment panel be sized as per Article 220 Part II, and the feeder between the meter bank and the service switchboard per Article 220 Part III?
      The two separate calculation methods are acceptable, but not required.

    1. Regarding (a) above, is there any other section in the code that requires the individual panel feeders to be calculated as per Article 220 Part III?
      There is no other section in the code that requires this calculation.

  1. A feeder with 6 conductors rated at 90ºC, installed in a raceway, is terminated in 75ºC rated devices. Can the higher temperature rating of the conductors be used for ampacity adjustments as stated in section 110.14(C)?
    Yes, for derating purposes associated with the number of conductors in the raceway.

Section 220.32 - (4/5/2006)

  1. A fan coil unit (FCU) consists of hydronic coils and a fan that circulates room air over the coils. Are FCUs considered to be "electric air conditioning" and if so, does the optional calculation method of Section 220.32 apply?

Section 220.32(A) - (5/3/2006)

    1. Section 220.32(A) lists the criteria for applying the optional calculation method. Is it correct to use the nameplate ratings of cooking equipment when applying the demand factor from Table 220.32?
      Yes, but not less than 8 kW.

    1. Can cooking equipment be defined as an oven and/or a range?
      Both ovens and ranges are considered cooking equipment.

    1. Is it correct to follow the examples of Appendix D of the NEC when using the nameplate ratings in the optional calculation method?
      See a. above.

  1. Regarding the exception of Section 220.32(A), when cooking equipment does not exist but all the other criteria of the same section are met, is it necessary to add 8,000 watts when using the optional calculation method?
    Yes, as per 220.32(A).

Section 230.42(A) - (4/5/2006)

    1. A utility service end box is located approximately 200 feet from the service switchboard. Should these conductors be included in the voltage drop calculation?
      Yes, the service conductors must be considered.

    1. Can the conductors between the service end box and the switchboard be considered feeders?
      No. They are service laterals. See Article 100.

    1. If these conductors are included in the voltage drop calculation, should the utility maximum demand output or the calculated load be considered in the calculation?
      If the utility current limits are available, they may be used in the calculation of the service conductors. If not, use amended Section 230.42(A) which limits amperage to 4000A.

  1. Should these conductors be considered as part of the utility service, and not part of the ownership responsibility for calculating the voltage drop?

Section 230.42(B) - (2/8/2006)

  1. For services under 1000 KVA, our interpretation of the code is that the current rating of the service entrance conductors is a function of the calculated load and does not necessarily need to match the rating of the service equipment overcurrent protection device.
    Case in point: for a calculated load of 1100 Amps with service entrance conductors of 4 sets of 4–500 kcmil and a service switch rated 1600 Amps, can the fuses in the service switch be rated 1600 Amps, thus exceeding the rating of the conductors?
    No. See section 230.42(B)

Section 230.43 - (10/16/2006)

  1. In response to two separate questions posed at the April 2006 and respectively June 2006 meetings, the Committee responded that rigid non-metallic conduit (RNMC) is not allowed for service entrance conductors. Please clarify whether RNMC (PVC or fiberglass) would be allowed as a wring method for service entrance conductors, if the conduits run underground and are encased in concrete.
    RNMC is not allowed as wiring method for service entrance conductors whether installed underground or encased in concrete. See Amendment to Section 230.43. However, special permission may be requested on a case by case basis.

Section 230.43 - (6/7/2006)

  1. We are requesting further clarification regarding two of the committee's recent interpretations.
      1. Power Distribution Unit (PDU).
        The April 5, 2006 committee minutes state that PDUs listed for IT applications shall not be used for other applications.
          1. Are PDUs listed for use in IT areas precluded from use outside such areas?

          1. Are PDUs listed for IT applications allowed for power distribution to IT equipment in dedicated rooms or rooms that do not utilize the wiring methods, and do not satisfy the conditions described in Article 645?

        1. Would a PDU listed for IT applications, but also having UL 67 panelboards as components, be permitted to be used in lieu of wall/floor mounted transformers and panels to supply general use loads such as workstation outlets, where raised floors are provided? The predominant load on such floors may consist of PC, printers, and other office equipment which may be listed as IT equipment.
          The PDU must be listed as an assembly for the application (UL 891) and meet the criteria of amended Article 408.

    1. PVC Conduits
      The April 5, 2006 committee minutes state that PVC conduit is not a recognized wiring method for underground service.
      The NY City amendments do not appear to prohibit the use of non-metallic conduit for underground work. Does the committee reaffirm the response that special permission is required for underground applications?

      Our response was for service wiring methods, and in accordance with the amended section 230.43. However, the use of nonmetallic (PVC) conduit for other applications, per Article 352, is permitted without special permission.

Section 240.24(B) - (6/7/2006)

  1. We are currently designing a mid-rise apartment building requiring supplemental electrical heating in some of the tenant bathrooms. Is it permissible to feed the electric heater(s) installed in the tenant bathroom(s) from the House Distribution panel(s) located in the basement in lieu of the tenant apartment panel?
    Yes, and must comply with section 240.24(B).

Section 250.2 - (2/8/2006)

  1. Is it permissible to use a ¼ 20 bolt, instead of lug, to bond the enclosure of a service switch? Connections for equipment bonding and grounding shall be made in accordance with section 250.2.

Section 250.122(A) - (2/8/2006)

  1. When applying Table 250.122 to a 25-foot tap [240.21(B)(2)], is it acceptable to size the equipment-grounding conductor based on the rating of the overcurrent protective device at the downstream end of the tap?
    No. See section 250.122(A).

Chapter 3: Wiring Methods and Materials (Code Section 300-1 to 384-37)

Section 310.15(B)(2)(a) - (11/9/2006)

  1. We are redesigning an existing installation that utilizes an underfloor raceway system. Articles 390- Underfloor Raceways, and 374 - Cellular Metal Floor Raceways permit a 40% maximum fill of the cross section area, while Article 376 - Metal Wireways allows only a 20% fill with the derating factors of 310.15(B)(2)(a) applied to a number of conductors exceeding 30.
      1. If the existing installation is left the same and the downstream branch wiring is re-used, do we need to make any changes to the existing wiring condition?
        No, if used in accordance with the original intent.

    1. For new installations, what are the derating requirements applicable to Articles 374 and 390?
      The derating factors should be in accordance with 310.15(B)(2)(a).

Section 314.28(A) - (7/19/2006)

    1. Cable Limiters
      Parallel service entrance conductors (SEC) under 600 volt are installed between an outdoor property box and a current transformer cabinet which is mounted adjacent to the service disconnect inside the building. The utility company requires that the parallel SEC have cable limiters in the property box at the point of utility-to-customer connection. Is there a code requirement to provide cable limiters at the other end of the SEC inside the building? If yes, where?


    1. Pull/Junction Box Sizing #1
      Section 314.28(A) addresses the minimum sizes for pull boxes containing conductors size 4 AWG and larger. When installing a service with an underground utility feed, the utility company requires the use of a service end box that must meet their specification.
        1. Do the requirements of Section 314.28(A) apply to these service end boxes?

        1. If yes, does it apply to the customer side conduits?

      1. If yes, does it apply to the utility side conduits?

  1. Pull/Junction Box Sizing #2
    Section 314.28(A) is also applicable to sizing wireways used as pull boxes [376.23(B)]. In the 2005 NEC this section also applies to auxiliary gutters (not yet adopted in NYC). In many installations equipment is mounted above and below pull boxes and wireways using short sections of conduit or nipples. In these instances the wire is not "pulled" but "placed." There appears to be no exception in 314.28(A) for applications involving short sections of conduit. We also note that if the short sections of conduit were replaced by short sections of wireway, Section 314.28(A) would not apply.
      1. Considering that the minimum bending space is provided, can an exception to 314.28(A) be allowed where the conduits involved at pull/junction boxes are 24" in length or less? [The 24" limit was chosen to be similar with 310.15(B)(2) Exception No. 3.]

      1. If no, 12" in length of less?

    1. If no, for offset nipples?

Section 330.10 - (7/19/2006)

  1. Is it permissible to use MC Cable (Section 330. 10) as risers in an apartment building, and to use cable tray in the basement to secure multiple feeders between the meter bank and the riser locations?

Section 330.12 - (11/9/2006)

  1. We are manufacturers of a MC-Jacketed Cable, that is listed for direct burial, concrete encasement, and wet locations. The outer jacket is made of sunlight resistant PVC. In accordance with NEC Article 330, is this product acceptable for use in a parking garage in NY City?
    Yes, PVC Jacketed MC Cable is permitted to be installed in parking garages subject to compliance with Section 330.12 and NYC amendment 330.10(A)(1). When installed exposed, use is permitted only in open garages with no occupied building structures above.

Section 330.30 & 310.15(B)(2) - (1/4/2006)

  1. We are planning to install a number of MC cables in the space above a drop ceiling. Is it permissible to bundle the horizontal runs of the MC cables?
    Yes, provided that the requirements of Sections 330.30 and 310.15(B)(2) are met.

Chapter 4: Equipment for General Use (Code Section 400-1 to 490-74)

Section 410.4(C)(4) - (2/8/2006)

  1. Is it permissible to install EMT, aluminum conduit or galvanized conduit exposed in a commercial cooking hood to feed light fixtures?
    No. See section 410.4(C)(4).

Section 422.31(b) - (10/16/2006)

  1. We have an appliance that is not within sight of the power panel. Section 422.31(B) requires a disconnect means for a permanently fixed appliance rated over 300 VA. In order to meet this requirement, is it permissible to use a circuit breaker lockable in open position?
    Yes. The circuit breaker padlock brackets must be listed.

Chapter 5: Special Occupancies (Code Section 500-1 to 555-11)

Section 517.35(B) - (1/4/2006)

  1. A doctor's office, located in a residential building, has a procedure room (with general anesthesia) which meets the definition of a Critical Care Area. Is an emergency generator required, as per Section 517.35 or is a central battery back-up system an acceptable alternate?
    An emergency generator is required as per Section 517.35(B). However, special permission may be requested from the Advisory Board for the use of a central battery back-up system.

Chapter 6: Special Equipment (Code Section 600-1 to 695-14)

Section 620.24 - (4/5/2006)

  1. Do the requirements of Sections 620.24(B) and 620.24(C), regarding elevator pit lighting switch and GFCI receptacle, apply to a private residence elevator?

Section 620.53 - (5/3/2006)

  1. Section 620.53 requires that single disconnecting means be used for an elevator car light, receptacle and ventilation circuit conductors. The disconnecting means shall be an enclosed externally operable fused motor circuit switch or circuit breaker.
      1. What is the meaning of externally operable?
        The definition for externally operable is: "capable of being operated without exposing the operator to contact with live parts", and could be found in Article 100 of the NEC.

    1. Can the disconnecting means be part of a distribution panel?
      A required individual lockable disconnecting means (switch or circuit breaker) may be mounted in a distribution panel. However, a lockable cover for the distribution panel does not meet the requirements of 620.53.

Section 645 - (4/5/2006)

    1. Article 645.10 requires "a means" to disconnect power to the electronic equipment in the room and "a similar means" to disconnect the power to all dedicated HVAC system serving the room and cause all required fire/smoke dampers to close. Is it acceptable to have more than one means for each of the two required functions to minimize the impact of inadvertent operation or a malfunction of a single means?
      Yes, based on the definition for disconnect means, which allows multiple devices with proper signage.

  1. Article 645.5(B) permits data processing systems to be cord and plug connected to a branch circuit. Information technology equipment, which are component elements of data processing systems, are typically rack mounted with single or dual corded input power cables plugged into multi-outlet assemblies within the racks. These assemblies are in turn cord and plug connected to the branch circuit conductors via an outlet located on or within the raised floor or overhead above the rack. Is the described cord and plug connected multi-outlet assembly acceptable as a wiring method under the provisions of Article 645, and not negated by Amendment 380.2(B)(7) which specifically prohibits their use?
    Yes, the assembly is a listed relocatable power tap. Amended section 380.2(B)(7) does not apply.

Section 680.23(B)(2)(b) - (6/7/2006)

  1. NYC Amendment 680.23(B)(2)(b) allows rigid non-metallic conduit with a #8 ground wire to be utilized from the forming shell of a Wet-Niche Luminaire to a suitable junction box. Is it permissible to use PVC conduit in a hi-rise building, when installed beneath the basement slab and turned up to a junction box 12 inch above the water line for this application?

Section 695.3(A)(1) - (12/6/2006)

  1. We are designing a truck maintenance/parking facility whose major loads will be large motors, exhaust fans, and HVAC equipment. The utility will provide three 120/208V, 4000A services. Our design includes: Stepping up 2 of the 3 services to 480/277V via 1,000KVA transformers and utilizing two 750KW, 480/277V generators connected in parallel. Is it permissible to feed the fire pump from the secondary of the 208 : 480/277V transformer? Both the normal and the emergency feeders would provide 480V.
    The transformer is considered to be a separately derived system. Accordingly, the use of a transformer for a fire pump is permitted. However, a dedicated transformer is required. See Section 695.3(A)(1) for service connection requirements.

Section 695.4(B)(1) - (6/7/2006)

  1. The amended section 695.4(B)(1)(a) requires that the conductors to fire pumps larger than 30 HP have overcurrent protection fused at 600% of the motor full load current. This may be in conflict with section 695.6(D) which requires only short circuit protection, and raises the following questions:
      1. Since the amended 695.4(B)(1)(a) calls for fuses rated at 600% of the motor full load current, is the intent to use these fuses for short circuit protection, which an unfused switch cannot provide?

      1. Since the same section mentions only fuses, are circuit breakers acceptable?

    1. If circuit breakers are acceptable, will magnetic trip alone be acceptable to provide only short circuit protection, as required by section 695.6(D)?
      Yes, provided that the interrupting rating of the device is adequate

Section 695.4(B)(3)(d) - (12/6/2006)

  1. We are requesting further clarification of June 8, 2005 Committee interpretation relating to the location of the Fire Pump Service Switch. In its response, the Committee indicated that the 2004 edition of the code does not prohibit a fire pump service switch to be part of a switchboard line-up, as long as it occupies a dedicated cubicle. We are in the possession of an advance copy of the New York City Amendments to the 2005 NEC. In this document there is no longer an amendment to Section 695.3(A)(1) as was the case in the previous edition. Please clarify the 2007 NYC Electrical Code requirements for a fire pump switch.
    See NYC Amendment 695.4(B)(3)(d) to the 2005 NEC.

Chapter 7: Special Conditions (Code Section 700-1 to 780-7)

Section 700.1 - (10/16/2006)

  1. We are requesting further clarification of a February 2, 2006 committee interpretation relating to emergency and legally required stand-by loads. In response to a question regarding the supply of these loads, the Committee's answer indicated that the emergency loads must be supplied by an automatic transfer switch, while the legally required stand-by loads must be supplied by a separate automatic transfer switch. One of the NY City amendments to the 2005 NEC deletes Article 701- Legally Required Stand-by Systems in its entirety and adds a FPN stating: "All legally required stand-by systems are classified as emergency systems." By adding the FPN, is the intention to allow both the emergency and the legally required stand-by loads to be supplied by a common automatic transfer switch, unlike the previous code edition but the same as the old NY City Electrical Code?
    All emergency and legally required stand-by loads are designated as emergency systems, per the Amendment to Section 700.1, and must be supplied by a separate transfer switch than the one for optional stand-by loads (Article 702).

Section 700.6(D) - (2/8/2006)

  1. Section 700.6(D) of the NEC requires that the emergency loads, listed under Article 700, be supplied by a separate transfer switch from legally required standby loads (Article 701) and from optional standby loads (Article 702). Considering the NY City amendments to section 700.1 and to Article 701 (deletion), is only one transfer switch allowed to supply both the emergency loads and the standby loads?

Articles: A subdivision of a Chapter, comprised of a certain number of Sections

Article 210

  1. My coop apartment, located in an 84 unit building, is being renovated and I would like to find out the following:
      1. What receptacles in the kitchen and bathroom need to have GFCI protection?

      1. Can receptacles be located above a countertop with a sink, in either the kitchen or the bathroom?

    1. What are the appliances that require separate circuits?
    Please indicate the specific code sections applicable to the above. (12/6/2006)
    Numerous Articles apply, among which are 210 and 406. All work must be performed by a NYC licensed electrician.

Article 702

    1. In our original question regarding emergency generators that was presented at the October 11, 2006 meeting, we asked if it is permissible to install a gas-fired generator in a single family home. The committee's response states that stand-by-generators are permitted, making no reference to the gas-fired type. The answer also indicates that "other jurisdictions apply". Please clarify which are those jurisdictions. (12/6/2006)
      Although Article 702 does not prohibit the use of gas-fired generators, this issue is beyond the scope of this committee. The applicable jurisdictions includes the FDNY and the DEP, but not limited to.

    1. Is it permissible to install a stand-by generator in a single family home, to supply an elevator and the lighting and appliance loads?
      Stand-by generators are permitted as per Article 702. Other jurisdictions apply.

  1. An MRI facility is a tenant in a high-rise office building and would like to install an emergency generator within its space. The tenant's space contains an elevator that travels from the ground floor to the cellar and is used only by the tenant. It is our understanding that the tenant can install the voluntary generator strictly for his own use and that would not be required to energize the building's life safety loads. Is that true? (10/16/2006)
    Stand-by generators are permitted as per Article 702. Other jurisdictions apply.

Administrative: General Requirements

    1. We are designing the power supply for a Fire Communication System in a NYC firehouse, and we are proposing the following design: A 3-phase Automatic Transfer Switch (ATS) feeds 3 individual 120V, single-phase loads, such as fuse cut-outs. Each fuse cut-out is connected to different electrical loads. The ATS is protected by 3-pole circuit breakers on the line side. Is this installation permissible? (12/6/2006)
      The proposed design does not violate the requirements of the electrical code. Please clarify with FDNY.

    1. What section of the code provides the requirements for Low Voltage Electrical Work?
      See Section 27-3004 of the Administrative Part of the NYC Amendments.

    1. A dimming / lighting control system, such as Lutron Homeworks system, with the capability of controlling HVAC, security, audio-visual, lighting and other systems, operates at below 50V. Can a person other than a NYC Licensed Electrician install the Low Voltage end of this system?

    1. Where does the licensed Electrician's responsibility start and end with the above type of system? (10/16/2006)
      The complete system shall be installed by a NYC Licensed Electrician.

    1. We are requesting further clarification of a February 2, 2004 Committee interpretation relating to the rating of fuses for fire alarm fuse cutouts. In response to a question regarding the maximum fuse size for a fire alarm fuse cutout, the Committee's answer was: "The maximum fuse size for a fire alarm system fuse cutout panel is 90A, as per RS-17-3." A review of the NYC Building Code Reference Standard RS-17-3 and of the NYC Electrical Code did not indicate any limitation in the fuse rating for the fire alarm fuse cutouts. Please clarify what was the basis for the decision, and whether the stated requirement is reaffirmed and in effect. (9/6/2006)
      The 90A limitation was historically adequate to supply the fire alarm systems. Where fire alarm systems requirements exceed 90A, larger fuses may be used.

    1. It is our understanding that Information Technology (IT) equipment cannot be installed within Electric Closets, while electrical equipment is permitted to be installed within IT Closets. We cannot find the Code section stating the above. Please clarify. (9/6/2006) An Electrical Closet is considered to be a room containing substantial electrical distribution equipment such as vertical risers, bus ducts, transformers, or panelboards. IT equipment and electrical equipment are permitted in other rooms or spaces, subject to compliance with the clearance requirements of Article 110.

    1. We are designing the power supply for a Fire Communication System in a NYC firehouse.
        1. Is it permissible for multiple UL Listed Fuse Cutouts to be placed in a custom made cabinet enclosure?
          Yes, as long as the enclosure is a listed assembly.

      1. Is it permissible for an Automatic Transfer Switch to feed multiple, single phase, 115 volt Fuse Cut Outs individually on separate legs of the 3 phase load side of the ATS? (7/19/2006)

    1. The lateral feed that runs inside the owner's property between the end-line box and the switchboard, is included in the voltage drop calculation. Can the City make provisions with the utility to furnish the owner the necessary paper work showing the maximum available current on the take-off? (6/7/2006)
      The City cannot enforce such a requirement on the utility. It is recommended that during the design stage, the owner requests such information from the utility.

    1. Must electric radiant heating for snow melting purposes on sidewalks and exterior ramp-ways of residences and buildings be installed by a licensed electrician? (6/7/2006)

    1. An existing standpipe is feeding a two pole 100A circuit breaker that is mounted in a 125A rated enclosure. The existing wires are #2 AWG Aluminum, protected by the 100A breaker. Is it permissible to replace the 100A breaker with a new 125A breaker? (5/3/2006)
      The ampacity of the service conductors must be based on the rating of the service disconnecting means.

    1. When we filed the requests for four work permits, we did not indicate the need for temporary service. At these sites, power is being obtained from services installed under previous contracts by other electrical contractors. The owner of the buildings has expressed concern that allowing us to use electrical energy from electrical services under their control is a violation of Section 27-3020 of the old New York City Electrical Code. In order for us to energize the electrical equipment installed under the four permits and contract:
        1. Is either a temporary or a final certificate of inspection required from the Department of Buildings, or are our permits as filed adequate to allow the electricity to be supplied from the owner's existing services?
          Yes, a final certificate of inspection is required.

      1. Do the four permits represent a temporary certificate of inspection? (4/5/2006)

    1. Section 645-17 was added to the 2005 NEC and allows the use of Power Distribution Units (PDU) in Information Technology (IT) applications. Can PDUs be used in lieu of wall/floor mounted transformers and panels servicing general use loads such as workstation outlets, where raised floors are provided? (4/5/2006)
      PDUs listed for IT applications shall not be used for other applications.

    1. A one family residential dwelling with a small commercial office is located approximately 100 feet from the waterfront. Due to the highly corrosive environment, we are considering using 2 sets of 4 inch Schedule 40 PVC conduit for the electrical service, 24 inch below grade. Is this acceptable? (4/5/2006)
      PVC conduit is not a recognized wiring method. Special permission is required.

  1. Is it permissible to connect a disconnect switch to the secondary side of a transformer through a rigid nipple, when the switch is mounted on a Kindorf next to the transformer? (3/8/2006)
    The electrical code does not restrict such installations.

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