2010 Code Interpretations

Buildings


Code DevelopmentNYC CodesSustainabilityReference

2022 Construction Codes
2014 Construction Codes
Energy Conservation Code
Electrical Code
Past Codes
Code Tools

2022 Construction Codes

2014 Construction Codes

Energy Conservation Code

Electrical Code

Past Codes

Code Tools


2010 Code Revision and Interpretation Committee Code Interpretation (Last Updated: February 23, 2011)

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 2005 edition of the NEC and the associated NYC Amendments to the 2005 NEC, as well as (Local Law 49/06) that went into effect on January 1, 2007.

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.

Expand AllCollapse All

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

Chapter 1: General (Section 110.2 to 110.79)

Section 110 - (12/1/2010)

Is the handle of a switch or the tab of a circuit breaker part of the definition of enclosure as per Article 100? (b) Does the handle of a switch or an exterior lock on a panel board count towards the depth of a working space?
No.

Does Section 110.25 prohibit the placement of electrical distribution equipment in a Mechanical Room?
No.
After much discussion the answer above will remain as it has been agreed by all parties that due to the fact that the handles of switches and circuit breakers are not added into the working space equation when such applications are submitted for review by the Advisory Board. Those answers that were discussed at the July 7, 2010 ECRIC meeting, which were eventually posted on DOB website will be rescinded.

Section 110.25 - (5/5/2010)

Do a transformer and the related branch circuit panels supplying a single floor constitute "substantial electrical distribution equipment" which requires an electric closet as defined in Article 100 or a dedicated room as required under Section 110.25?
No, in either case.

Does Section 110.25 prohibit the placement of electrical distribution equipment in a Mechanical Room?
No.

Section 110.26 - (3/3/2010)

In an electrical closet, there is a dedicated area for future risers located opposite a wall mounted 480/277V lighting panel. The opening in the floor for the riser's chase is surrounded by a curb that is 6 inches deep and 6 inches high. The horizontal clearance between the panelboard and the riser space is 42 inches, while the one between the panelboard and the curb is 36 inches (Download the attachment). Is this installation code compliant?
No.

Section 110.26 - (7/7/2010)

Is the handle of a switch or the tab of a circuit breaker part of the definition of enclosure as per Article 100?
Yes, as per Section 110.26(a)(1).

Does the handle of a switch or a exterior lock on a panel board count towards the depth of a working space?
Yes

Section 110.26(F)(1) - (5/5/2010)

An electric panel, 40 inch wide and 6 inch deep, is located in an electric closet that is 48 inch wide and 12 inch deep. A 12 inch X 8 inch dryer exhaust duct was installed over the panel, with a clearance of 16 inches. According to Section 110.26(F)(1)(b), foreign systems shall be permitted in the dedicated space above a panel, provided that protection is installed to avoid damage to the electrical equipment from condensation or leaks. If a drip pan is installed under the duct, can the panel remain at its present location?
No. Foreign systems, such as a dryer exhaust duct, cannot be installed in a dedicated electrical space as described in Section 110.26(F)(1)(a). Section 110.26(F)(1)(b) addresses foreign systems permitted above, but not in the dedicated space.

Chapter 2: Wiring and Protection - (Code Section 200.1 to 285.25)

Section 210.12 - (7/7/2010)

Customer requests replacement in kind two obsolete electrical panels serving a hotel suite with permanent provisions for cooking. Panels are 1 phase 3 wire and 3 phase 4 wires and the wiring for the receptacles are embedded in masonry walls and most of the circuits have shared neutrals. Do the new panels have to be provided with arc fault circuit-interrupter protection?
No, only if the existing circuitry remains in place. If new branch circuitry is installed from the panel to the bedrooms then arc-fault circuit interrupters (AFCI) protection is required.

Section 210.52(B)(2) & 220.12- (4/7/2010)

Regarding a switch controlled receptacle located in a residential dining room:

Can the receptacle be connected to one of the two or more required small- appliance branch circuits?
No. See section 210.52(B)(2).

Is the receptacle defined as a continuous load?
No. See section 220.12.

Is such receptacle defined as a permanently connected luminaire?
No.

Section 215.2 - (3/3/2010)

Exception No.2 of the NY City amendment to Section 215.2 states: "for residential occupancies...the maximum voltage drop from the service point to the last overcurrent device shall not exceed 4% and the total maximum voltage drop to the last outlet shall not exceed 5%. Since this exception is not limited only to dwelling unit loads, are we correct to assume that it also applies to all the loads (apartment, mechanical & public area loads) within residential occupancies class J1 & J2?
No.

Section 220 - (12/1/2010)

An existing apartment has 2 electrical risers; each of them is rated at 85 amps, 115 volt and protected with 50 amp single-pole circuit breaker in the basement of the building. The apartment is being fully renovated and new electrical panels are being provided and all branch circuits are being replaced. The load calculation indicates that the capacity of the existing riser is adequate and voltage drop is within 3%. Can existing risers be re-used or must a new 208 volt, single-phase riser be provided to satisfy requirements of Article 215.2(A)(1)?
Yes, each of the two existing feeders may be re-used to individually supply a new panel provided it meets the minimum calculated feeder required for the new loads connected to each new panel in accordance with Article 220.

Section 220.43 (B) - (3/3/2010)

We are in the process of designing an extensive track lighting system for a museum. Section 220.43(B) requires that for every 2 feet of track lighting an additional load of 150VA must be included into the feeder and service load calculations. Our design will include permanently installed current limiting devices which will not allow the track to carry the 150VA / 2 feet required by this Section.

Is it permissible to size the service conductors based on the maximum allowed capacity of the current limited track?
No.

For low voltage track lighting (less than 30V), does Section 220.43(B) apply? Or should the additional load be based on the maximum VA rating of the transformer?
Section 220.43(B) applies, unless the entire system meets the definition in Section 411.2, in which case Article 411 applies.

Section 220.84 and 230.70 - (7/7/2010)

We are the building engineers for many residential buildings in NYC and we are involved in reviewing many apartment alterations. Very often we have a situation, when two (2) or more individual apartments had been combined together, however, the individual apartment risers, electrical meters and protection equipment had been re-used. Sometimes protection equipment for the individual apartments' risers are located in different rooms or electrical closets. Our interpretation of the Code is that only one main switch shall be able to shut down the power in the entire apartment in case of fire or any other emergency situation. Please advise if this interpretation is correct or multiple switches can be used for a combined apartment.
No, your interpretation of the code is incorrect and multiple switches may be employed provided the switches are permanently identified.

Section 230 - (12/1/2010)

Section 230.70(A) (1) (Readily Accessible Location) - The service disconnecting means shall be installed at a readily accessible location inside of a building or structure nearest the point of entrance of the service conductors. Section 230.43(14) lists mineral-insulated, metal-sheathed cable as a type of wiring method that can be installed for service entrance conductors. Section 230.6 (Conductors Considered Outside of the Building) - Conductors shall be considered outside of the building or other structure under any of the following:

Where installed under not less than 2" of concrete beneath a building or structure.

Where installed within a building or other structure in a raceway that is encased in concrete or brick not less than 2" thick.

Where installed in any vault that meets the construction requirements of Article 450, Part III (deleted)

Where installed in conduit and not under less than 18" of earth beneath a building or other structure.

Back in 1999 when New York City was still using the old NYC Electrical Code Tyco Thermal Controls was given special permission for the 1850-SE System (which consist of fire-rated MI cable installed in a tamper resistant ventilated trough with caution signage affixed to the entire length of the trough) to use to extend service entrance conductors inside of a building or other structure. If there are no amendments to Section 332 of the NYC Electrical Code and amendment and 230.6(3) has been deleted, can the 1850-SE System be used to extend service entrance conductors inside of a building or other structure?
No, special permission may be obtained from the Department of Buildings' Electrical Advisory Board.

Section 240 - (12/1/2010)

A single-phase apartment load center with a 2-pole, 200 Amp circuit breaker is fed from a 2-pole, 175 Amp circuit breaker in a distribution panel utilizing #2/0 AWG conductors. Is this installation code compliant?
Yes, provided conductors are copper and calculated loads does not exceed 175 Amps.

Section 240 - (12/1/2010)

May overcurrent device such as circuit breaker in a distribution panel be located more than 6'7" above floor of working platform if a second circuit breaker is installed on the load side of the subject branch circuit (with first breaker in distribution panel) in a readily accessible location and not higher than 6'7" above floor? The above is based on Sections 240.24(A) (3) and 230.921(a).No.

Section 240.24(D) - (1/6/2010)

We are considering installing a remote sub-meter in a kitchen pantry closet of an apartment located in an existing building. The closet has a full door, recessed shelves and enough space inside to install the meter. The meter dimensions are 8 in X 8 in X 1 in. Is it permissible to install the remote sub-meter in the pantry closet? The code addresses only overcurrent devices in clothes closets [section 240.24(D)].
Yes, provided that adequate accessibility to the equipment is maintained.

Section 250 - (12/1/2010)

Per Article 250.52(A)(2) the structural metal frame of a building where not in direct contact with earth is acceptable for use as a grounding electrode if bonded in accordance with either sub-paragraphs (2), (3) or (4) of that article.

For a reinforced concrete structure would the bonding of the column re-bar in a similar manner qualify the re-bar as an acceptable grounding electrode for the connection of grounding electrode conductors to multiple separately derived systems throughout the building?
No, pursuant to Section 250.30(A)(7) only metal water pipe and structural metal are acceptable methods of grounding electrodes.

Are there any specific requirements associated with the re-bar installation and sizing for it to qualify as a grounding electrode?
Question is moot as the bonding of column re-bars is not an acceptable method of grounding electrodes.

Would the bonding and grounding electrode conductor connection requirements be the same as that for the structural metal frame?
Is moot as the bonding of column re-bars is not an acceptable method of grounding electrodes.

The equipment grounding conductor (EGC) required between theservice switch and the utility company service?
No, Section 250.142 applies.

Should the requirement of question 1(a) above comply with Section 250.122?
No, should the equipment grounding conductor be installed then it is required to comply with Sections 250.92(B) and 250.102(C).

Is grounding and bonding required between the service switch and distribution?
Yes.

Should the requirement of question 2(a) above comply with Section 250.66?
No, it is required to comply with Section 250.102(D)

Section 250.64 (E) - (3/3/2010)

Provided that the requirements of Section 250.64(E) are met, is it permissible to run a grounding electrode conductor in the same conduit with the phase, neutral and equipment grounding conductors?
Yes, provided that all the requirements of Part III of Article 250 are met, and the grounding conductors are distinguishable from each other.

Section 250.66 & 250.122 - (7/7/2010)

For parallel service conductors running in multiple raceways, should the grounding electrode conductor be sized in accordance with Section 250.66 (rather than Section 250.122)?
Yes.

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

Section 410.73- (7/7/2010)

We are in the process of installing 6 rows of 12 luminaires per row for a total of 72 indoor luminaires. There will be six separate 20 amp circuits (6 hots, 6 neutrals and 6 equipment grounds) and six single-pole 20 amp switches to control the lighting in an open commercial space. (no offices) According to Section 410.73(G) Exception #5; it exempts to require ballast disconnects for the luminaires. Is my answer correct?
Yes.

Section 422.31(B) & 440.14 - (5/5/2010)

We are installing a mini-split ductless air conditioning system comprised of two components, an outdoor compressor / condenser unit (hermetic refrigerant motor-compressor) and an indoor unit (fan-coil unit(s)). The entire system is powered by a single branch circuit, which is connected to the outdoor unit via a disconnecting means located at the outdoor unit. Is a separate indoor disconnecting means required for the indoor unit?
Yes. However, a lockable branch circuit overcurrent protection device in the source branch circuit panel may serve as the disconnecting means for the indoor unit. See Sections 422.31(B) and 440.14

Chapter 7: Special Conditions - (Code Section 700.1 to 780.7)

Section 700 - (12/1/2010)

Scenario: Existing switchgear sections with crown boxes and riser pull boxes have several sets of utility supplied conductors traveling to their respective load(s). It is intended to selectively convert some of the existing utility conductors into emergency conductors while they remain within their respective crown box or pull box.

Is it permissible to install a "barrier" within a crown box/junction box/pull box that will separate the emergency conductors from other systems and be compliant with 700.9?
No.

Is it permissible to arc tape the utility supplied and the conductors from other systems and be compliant with 700.9?
No.

Pursuant to Section 700.9(B) (2), only fire rated emergency feeders are permissible to be run inside service room.

Section 700.9(B) - (1/6/2010)

A 1000 kW, 480 / 277V emergency generator will be installed at a campus site to serve two buildings, one new, the second existing. The new building will be designed and built in two phases, with the 2nd phase occurring in the next 5-10 years. In the existing building, the generator will supply only life safety loads via the Emergency Generator Switchboard (EGS), while in the new building the generator will supply life safety loads as well as standby loads via the Emergency Distribution Switchboard (EDS). The EDS will receive emergency power from the EGS via a 1200A circuit breaker and a common feeder (3 sets of 600MCM).

According to section 700.9(B), paragraphs 1 thru 4, is it permissible to supply the life safety loads and the standby loads via the common feeder running from the generator to the new building?
Yes. However, inside the new building, the life safety loads must be kept entirely independent from the stand by loads.

Is vertical separation required between the 1200A breaker section and the neighboring sections in the EGS?
No. See Section 700.9(B) under the current Electrical Code. For Phase 2 of design and construction, the installation will have to comply with the code in effect at the time of implementation.

Section 700.9 - (7/7/2010)

We are the consulting engineer working on a 9-story building in Queens. There is an existing emergency (EM) generator located on the roof. Emergency feeders from the generator to ATS's located in the basement are conduit with THHN type conductors. We are relocating portion of those emergency feeders to accommodate program changes to one of the floors. Please provide interpretation for the following: Do re-routed emergency feeders have to comply with 700.9(D)?Yes.

Chapter 8: Communications Systems - Code Section 800.1 to 830.179)

Section 800 - (12/1/2010)

Does the installation of types: AC, FC, FCC, IGS, MV, MC, MI, NM, TC, SE, USE, UF, IMC, EMT, RMC, FMC, LFNC, NRC, LFMC, LNMFC, HDPE, NUCC, FMT, ENT, auxiliary gutters, busways, cable bus, cellular concrete floor raceways, cellular metal floor raceways, metal wireways, non-metallic wireways, mutli-outlet assembly, non-metallic extensions, strut-type channel raceways, surface metal raceways, non-metallic surface raceways, under floor raceways and cable trays have to be installed by a licensed master electrician or special licensed electrician holder even if these above methods are used for low-voltage, security or data communication wiring?
Yes; pursuant to §27-3017(a)(1) of the New York City Electrical Code. Please be advised that most of wiring methods listed here are suitable only for power circuits and that Section 800.113 prohibits the use of any conductor that has a voltage marking for communication circuits.

Section 800 - (12/1/2010)

With regard to the installation of data, co-axial, telephone, signal and other communication/low voltage cabling; are we required to adhere to chapter 9, table 1 for conduit fill? Please also see 90.3 for reference.
No, Exception to Section 800.110.

With regard to data cabling installations (cabling which begins at a patch panel and terminates at a jack/computer/fax/phone), does article 800 cover those installations?
Yes.

Section 800 - (7/7/2010)

With regard to the installation of data, coaxial, telephone, signal and other communication/low voltage cabling; are we required to adhere to chapter 9, table 1 for conduit fill? Please also see 90.3 for reference.
The conduit fill shall be in accordance with the article that covers the usage of these cables.

With regard to data cabling installations (cabling which begins at a patch panel and terminates at a jack/computer/fax/phone), does article 800 cover those installations?
The conduit fill shall be in accordance with the article that covers the usage of these cables.

Annex D: Calculation Examples

Annex D - (3/3/2010)

We are requesting further clarification of a February 7, 2007 Committee interpretation relating to load calculations. In response to a question regarding the final computed load for multi-family dwellings, the Committee's answer indicated that this load is considered continuous. Examples D3 and D3(a) of Annex D of the 2005 NEC show that the calculated load for sizing the overcurrent devices in non-residential occupancies is obtained by using 100% of non-continuous load plus 125% of the continuous load. However, Examples D4(a) and D4(b) for dwelling occupancies, do not assign a 125% continuous load factor to any component of the total calculated load. Please revisit the original response. Are Examples D4(a) and D4(b) applicable to multi-family dwellings?
Yes. Examples D4(a) and D4(b) show the applicable calculations for determining the final loads in multi-family dwellings. This applies to calculations for dwelling unit loads only.

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

Article 110 - (9/8/2010)

A Con Ed rep has told us that they govern clearance requirements in front of C.T. cabinets and not the NYC Electrical Code. This is for a C.T. cabinet to be located on the secondary side of the building main service switch upstream of the second over-current device. They want to approve a 30" clear space in lieu of the 36" required by code. Do they have the authority to authorize this and will it be accepted by BEC?
No, 3 foot clearance required under Table 110.26(A) (1)

Article 250 - (9/8/2010)

While Using 250.122(F) (1) as reference - Please consider a feeder protected by a 4000A upstream fuse without ground fault protection. Is the use of a 500MCM equipment grounding conductor in each paralleled conduit code compliant?
Yes.

Please consider a feeder protected by a 4000A upstream fuse with ground fault protection set at 400A. Assuming conditions 1, 2 and 3 of Section 250.122(F) (2) are met, is the use of a #3 copper equipment grounding conductor in each paralleled conduit code compliant?
No. Section 250.122 (F)(2) deals only with multi-conductor cables.

While using Table 250.122 as reference - The size of the equipment grounding conductor for an unprotected service conductor cannot be directly determined from Table 250.122. Please consider a building with a remote service end box. The service conductors between the service end box and the electrical service room are run underground in PVC.

Can the service conductors be run in PVC without an equipment grounding conductor?
Yes, as per Section 250.142.

If the answer to question (i) above is no, can the equipment grounding conductor be sized in accordance with the utility's over-current protection device?
No answer necessary

If the answer to question (i) is no, can the equipment grounding conductor be sized based on the utility's feeder size and relative over-current protective device based on Section 240.4?
No answer necessary

If the answers to questions A, B and C are all no, is there a method for determining the size of the equipment grounding conductor for service conductors run in PVC?
No answer necessary

Article 300 - (5/5/2010)

Is it permissible to use Liquidtight Flexible Metal Conduit (Sealtight) in lengths exceeding 6 feet, for Class 2 circuits? The FPN to Section 725.1 states that the wiring methods specified in Chapters 1 - 4 do not apply to class 2 wiring.
Yes, equipment used in emergency systems must comply with Article 700.

Article 400 - (9/8/2010)

In an educational facility the owner/architect is proposing that we install a receptacle in a surface mounted box in a millwork work station. The receptacle will be mounted below the work surface and behind an access panel (the access panel does NOT require tools to be removed). A grommet will be installed in the work surface. A cord and plug device will be installed on the work surface. It is proposed to run the cord from the device through the grommet and down to the receptacle mounted in the millwork. Is this installation acceptable?
Yes, as per Section 400.7(a)(3)

In an education facility the owner/architect is proposing that we install a receptacle in a surface mounted box in a millwork desk. The receptacle will be mounted below the work surface and behind an access panel (the access panel does NOT require tools to be removed). It is proposed to install flush mounted table top box similar to a FSR-T3U-3. The box contains four receptacles. These receptacles are fed from a factory assembled NEMA 5-20P SJ cord set. It is proposed to plug this cord set into the receptacle mounted in the desk. Is this installation acceptable?
No, as per Section 400.8 #1. Portable (not permanently mounted) is allowed with cord and plug whereas permanently installed is not allowed to be connected with cord and plug.

Article 700 - (4/7/2010)

We are planning to install a cogeneration unit in an existing high-rise residential building that has no emergency generator. The 100 Kw cogeneration unit runs on natural gas and has the ability of operating as a stand-alone generator, upon loss of utility power.
The cogen unit is listed for compliance with UL 1741 (Inverters, Converters, Controllers and Interconnection System Equipment for Use with Distributed Energy Resources), but not with UL 2200 (Stationary Engine Generator Assemblies). In the event of a utility outage, it takes longer than 10 seconds for the unit to transition from interconnected mode to stand-alone generation mode. The building ownership is interested in utilizing the cogen unit in stand-alone mode to power building loads (including elevators and emergency lighting) in the event of a long term utility outage.

Do the requirements of Article 700 (including availability within 10 seconds) apply to the cogen unit when operating in stand-alone generation mode?

Can this cogen unit be used in stand-alone mode as a voluntarily installed emergency generator to supply elevators and emergency lighting during utility outage?

If the answer to (b) is "No", can this cogen unit be used in stand-alone mode to supply non-life safety loads only?

No. The requirements of Article 300 apply to Liquidtight Flexible Metal Conduit, even if used for Class 2 wiring. See Section 90.3.

Article 700 - (4/7/2010)

We are requesting further clarification of a January 6, 2010 Committee interpretation relating to emergency feeders. In response to the question of whether it is permissible to supply life safety loads and standby loads via a common campus emergency feeder, the Committee's answer was "Yes". We have a similar case where a Fire Alarm Panel (FAP) is being installed in a building serviced by a campus emergency feeder. The FAP will be connected via a dedicated 30 Amp ATS. Is it permissible to tap the common emergency feeder ahead of any switching device, in order to connect the 30 Amp ATS?
Yes.

Article 760 - (9/8/2010)

An existing low-rise nursing home has the existing fire alarm fused cutout tapped ahead of the main and the existing emergency lighting panel board tapped ahead of the main. The owner is planning to install an emergency generator and automatic transfer switch (ATS) to feed the emergency lighting panel board. The generator will have a main circuit breaker. There is no work planned to the existing fire alarm system.

Can the owner leave the existing fire alarm fused cutout tapped ahead of the main?
Yes, with inclusion of emergency supply as per responses below.

Is the owner obligated to connect the existing fire alarm system power supply to the generator?
Yes.

If the owner voluntarily elects to connect the fire alarm system to the generator, can he do so by tapping the load side of the ATS ahead of the emergency lighting panel board?
Question is moot as the owner is required to connect the fire alarm system to the generator.

If the owner voluntarily elects to connect the fire alarm system to the generator, will the fire alarm system require a dedicated ATS?
Yes.

The NYC 2011 Electrical Code – Administrative Provisions and 2008 NEC Amendments is now on sale on the CityStore.

Other Code Interpretation Links:

Code Interpretation for 2023

Code Interpretation for 2022

Code Interpretation for 2021

Code Interpretation for 2020

Code Interpretation for 2019

Code Interpretation for 2018

Code Interpretation for 2017

Code Interpretation for 2016

Code Interpretation for 2015

Code Interpretation for 2014

Code Interpretation for 2013

Code Interpretation for 2012

Code Interpretation for 2011

Code Interpretation for 2009

Code Interpretation for 2008

Code Interpretation for 2007

Code Interpretation for 2006

Code Interpretation for 2005

Code Interpretation for 2004

Code Interpretation for 2003