2005 Code Revision And Interpretation Committee Code Interpretation (Last Updated: January 13, 2006)
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 1: General (Section 110-2/110-59)
- Section 330.12 of the 2002 NEC lists the uses not permitted for type MC cable, among them: direct burial, in concrete, and where exposed to cinder fills. In the 2005 NEC, the FPN added to the same section clarifies that MC cable identified for direct burial is suitable for concrete installation. Can MC cable be installed in concrete as noted above? (6/8/2005)
The cable shall be installed in accordance with its listing. See Section 110.3(B).
- Article 110.14-Electrical Terminations, Paragraph(C)-Temperature Limitations,states that "temperatures higher than those specified for terminations shall be permitted to be used for ampacity adjustment, correction, or both." Can the 90° C ampacity be used for derating purposes? (10/19/2005)
- We are in the process of designing several 8-family residential apartment buildings. Is it permissible to install the electrical service, distribution and metering equipment within the same room as the water service, the gas service and the associated metering equipment? (4/6/2005)
It is acceptable to install electrical service equipment in the same room with the other utility services. Minimum clearances must be maintained as required by Section 110.26.
- We are installing a 1200A, 120/208V service in an electrical room whose height is 7 feet. The hallway leading to the electrical room is 5 feet high. Is there a minimum height requirement for hallways? (9/7/2005)
The height requirements for the door to the electrical room shall conform with Section 110.26 (C) (2), and the height requirements for the hallway shall conform with the requirements of the New York City Building Code.
Chapter 2: Wiring and Protection (Code Section 200-1 to 280-25)
- A 480V motor is being fed by a circuit from Service "A", whose overcurrent protective device is the 3rd level from the service point. The motor has a 120V space heater that is fed by a circuit from Service "B", whose over current protective device is also the 3rd level from the service point. Both circuit terminations at the motor are made in the same terminal enclosure.
- Is a barrier required in the terminal enclosure, as per Exception 2 of Section 300.3(C) (1)?
No, for 3rd level protective devices. However, the two circuits shall be properly identified in accordance with Section 210.4(D).
- If so, would the barrier still be required if a sign is used to indicate the presence of multiple sources? (9/7/2005)
- The basement of a two family dwelling has the walls finished with sheetrock and a concrete floor without any covering. There are no walls or partitions. Are the receptacles installed around the basement required to be GFCI protected? (6/8/2005)
The basement spaces must be wired in accordance with DOB approved plans. GFCI protection is required in unfinished basements. See Section 210.8.
- Does a 110 Volt receptacle installed within a basement boiler room require GFCI protection?
For dwelling units, Yes. For other than dwelling units, No. Section 210.8.
- Does a 110 Volt receptacle supplying a sump pump, via a plug and cord, require GFCI protection? (1/19/2005)
Not if it's a single receptacle, dedicated to the pump. Section 210.8.
- A wheelchair lift was installed outside a one family dwelling, hardwired to the electrical system. Is a Ground Fault Circuit Interrupter (GFCI) required? (10/19/2005)
- Section 212.12(B) requires Arc Fault Protection (AFP) for bedroom outlets in dwelling units. Is AFP required for a 20A dedicated outlet, serving life sustaining equipment? (2/9/2005)
Yes. Section 210.12(B) applies.
- Are AFCIs required for receptacles installed in the sleeping areas of:
If the occupancy conforms with the definition for a dwelling unit of Article 100, then AFCI protection is required.
- Hotel/motel rooms and suites, as stipulated in the amended Section 210.12(B)?
- School dormitories and similar occupancies that do not have provisions for cooking, but comply with the requirements for living, sleeping and sanitation?
- Is there a code amendment regarding AFCI protection in dwelling units? (9/7/2005)
Yes. See Section 210.12(B).
- A college dormitory, classified as a J-2 occupancy, has dwelling units with spaces for eating, living, sleeping, cooking and sanitation. The furniture in these units is not fixed in place. Is it permissible to locate receptacle outlets in the dwelling units in accordance with Section 210.60(B) in lieu of Section 210.52(A)? (6/8/2005)
Spacing of electrical receptacle outlets must be in accordance with Section 210.52. However, Section 210.60(B) may only be applied with special permission, if the furniture is fixed in place and permanent provisions for cooking and sanitation are provided within each unit.
- What is the minimum feeder size for an apartment of a three family dwelling, if the calculated load is 29.5 Amps and the length of the feeder is sixty feet? Does the amended Section 215.2(A)(1) apply? (12/7/2005)
The minimum feeder size is 3 x #8 AWG. The amended Section 215.2(A)(1) applies.
- Section 220.18 requires that "Where two or more single-phase dryers are supplied by a 3-phase, 4-wire feeder or service, the total load shall be computed on the basis of twice the maximum number connected between any two phases." Additionally, Table 220.18 provides the Demand Factor to be used for calculating feeder sizes for electric clothes dryers. This table is clear only when the numbers of dryers are "1-11", "23" and "43 and over."
- How should the total load be computed for a 15 story apartment building with a single phase, 208V, 5000W dryer on every floor (total of 15)? Each dryer is fed by a power panel located on the same floor.
Using Table 220.18 as stated, the total load is calculated as follows:
5 dryers/phase x 2 = 10 total, for a 50% demand factor.
- What demand factor should be used for determining the feeder size? (4/6/2005)
When the number of dryers is between 12-22, the demand factor decreases by 1% per dryer. Between 24-42 dryers, the demand factor decreases by 0.5% per dryer.
Section 220.32(A)(2) & 220.15
- The exception to Section 220.32(A)(2) allows the optional calculation method to be used for dwelling units without electric cooking. Can the same exception be extended to an apartment with electric cooking and heating/cooling fan coil units? We request special permission to use this method.
No. Special permission should be requested from the Advisory Board.
- What is the definition for a heating / cooling fan coil unit (FCU)?
Electrical code does not define FCU.
- For an apartment with supplemental space heating (i.e. window baseboard heating and bathroom floor mat heating), should the heating requirements be as per Section 220.15? (12/7/2005)
Section 225.30, 240.21, 404.8 & 450.3(B)
- When tapping parallel conductors, there are two methods available: one using 2 single connectors/phase, and a second using 1 double connector/phase. Which of the two methods is code compliant?
From the two methods described, only the second method is acceptable.
- Is it permissible to mount a safety switch flat on a ceiling (with the cover facing the floor), when:
- Used as the local disconnecting means for an air handling unit suspended from the ceiling?
Yes, when conforming to Section 404.8, Exception 2.
- Used for any other purpose?
Refer to Section 404.8.
- A large medical facility has multiple buildings that are connected and used as one facility. The facility has one tax lot and has one DOB filing address. Each building has its own separate electric utility service and its own emergency generator. Is it permissible to have electric wiring in one building originate from the electric service located in one of the other buildings, without the use of atransfer switch? If yes, are there any labeling requirements?
Yes. The installation shall be in accordance with Section 225. 30.
- Table 450.3 (B) sets forth overcurrent protection requirements for transformers 600 volts and less. Line 1 of the table "Primary only protection" shows that secondary for transformers with current ratings of 9 Amps or more, where the primary overcurrent protection is "Not required" is protected at not more than 125% of the transformer current rating.
Section 240.21(C) "Protection by Primary Overcurrent Device", shows that except for single phase 2-wire transformers and delta-delta 3-wire transformers with single voltage secondary, transformer secondary conductors are not considered to be protected by primary overcurrent protective device.
It appears that there is a conflict between the requirements of table 450.3(B) and those of Section 240.21(C) (1). Which requirements take precedence? (9/7/2005)
There is no conflict between the two sets of requirements. Table 450.3(B) provides the requirements for transformer overcurrent protection, while Section 240.21 provides the requirements for feeder overcurrent protection.
- A project involves the conversion of four individual single story commercial buildings, each with a separate block and lot number, into a single building with the addition of a second story. The four existing buildings and the 2nd story addition will be rezoned to a single block and lot. The 4 existing buildings are each presently provided with a dedicated Con Ed electric service consisting of an end box, service switch, meter, and related distribution. Is it acceptable to maintain the individual services and disconnect all services from a single remote location via a contactor or similar device installed at each individual service? (1/19/2005)
No. See Section 230.43
- Under the new code:
- Are two separate general purpose circuits still required in a living room?
- Is the use of PVC still allowed on a basement ceiling?
Yes, in one and two family homes, if physically protected.
- Can the wires for service entrance conductors be stepped down one size (i.e. for 200 A, from 3/0 to 2/0)?
- Is the use of exposed BX allowed on a basement ceiling?
Yes, where physically protected.
- Can PVC be used for Con Edison sleeves for new services? (6/8/2005)
Yes, for sleeves. No, for conduits. See Section 230.2.
- For an installation consisting of more than two 2-wire branch circuits, can the rating of the service disconnecting means be less than 60A? (9/7/2005)
No. See Section 230.79 (D).
Section 240.12 & 110.9
- Is it permissible to add to the load side of an existing service switch, with link fuses, a feeder with a fused disconnect switch (service is less than 1000 KVA)? (1/19/2005)
No. See Sections 240.12 and 110.9.
- Is the ampacity of the tap conductors for the fire alarm fuse cut-out required to comply with Section 240.21(B)(1)(4)?
No, for service conductors. Yes, for feeder conductors.
- A 4000A service is tapped with four sets of feeders rated at 1/3 (1334A) the rating of the service conductors. Should the rating of the overcurrent protective device for the tap conductors be less than 1600A, 1200A, 800A, 400A or with no limitation?
1200 A. See Section 240.21(B)(2).
- If the rating of the overcurrent protective device may be lower than the ampacity of the protected tap conductors, are there any other limitations in addition to the following?
The equipment shall conform with all the current code requirements.
- Enclosure shall be rated to accommodate line and load conductors (physical dimensions and heat dissipation).
- Overcurrent protective device termination lugs shall be rated to accommodate line and load conductors. (6/8/2005)
- An existing 1200A bus is tapped with a new 600A feeder. The feeder will be connected to a 600A fused main disconnect switch via a 600A ATS. The devices are located within 25 feet of the tap.
We believe that this design is in compliance with subsection 240.21(B)(4)(d) for the following reasons:
The 600A tap conductors terminate in a single main fused disconnect switch rated 600A, located inside a panel, which will limit the load to the ampacity of the tap conductors. The ATS is rated at 600A and is just a transfer device and does not introduce any additional loads. Therefore, the load on the tap conductors will be limited to 600A by the main fused disconnect inside the panel, as required by code. Is our interpretation of the code correct? (10/19/2005)
The tap conductors shall terminate in a single overcurrent device as required by subsection 240.21(B) (2)(2). In the described design, the tap conductors terminate in a transfer switch, which is not an overcurrent device. Accordingly, the proposed design is not code compliant.
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- Is it permissible to bond the neutral of a service switch with a green bonding screw, supplied by the manufacturer? If so, what is the maximum service switch size allowed to be bonded with a screw? (2/19/2005)
Yes. There is no size limit for the service switch, as long as it is listed. See Section 250.8.
- A store has a standpipe, meter and a 4 wire service switch. The store is being divided into two smaller stores, and we intend to add a second standpipe from the same service point, meter and service switch at the same location.
Is an additional ground required to be connected to the water main or will the bonding to the two service switches be sufficient? (12/7/2005)
Grounding and bonding is required. See Section 250.24.
- A 208V to 277/480V Delta/Wye step-up transformer usually comes with the center tap of the secondary bonded to the enclosure. As a separately derived system, the transformer must have its neutral connected to a supplemental ground (grounding rod or building steel).
The grounding and bonding shall be made at either location, transformer or switch. See Section 250.30(A)(1).
- Is it permissible to leave the manufacturer's center tap bonding intact and install a supplemental ground connected to the neutral bar of a switch or must the supplemental ground be connected to the center tap of the transformer secondary?
- Can the center tap be removed and the bonding and grounding be made in the switch? (7/6/2005)
- Is it permissible to install a grounding rod horizontally, through the foundation wall, approximately four to five feet below the grade? (6/8/2005)
The ground rod should be driven to a depth of 8 feet unless rock bottom is encountered. See Section 250.53(G).
- The load side of a 4000 Amp service switch, fused at 4000 Amp, is being tapped (ten foot tap) with 3 sets of 600KCMIL cables that are connected to a 1200 Amp disconnect switch. Is an equipment grounding conductor required, in addition to the metallic raceway? If so, what size should it be? (1/19/2005)
Where required, the size of the equipment grounding conductor shall be 500 KCMIL per set, as per Section 250.122.
Chapter 3: Wiring Methods and Materials (Code Section 300-1 to 384-37)
Section 300.1(B) & 110.2
- Which takes precedence, the product Calendar Number (issued in 2001) or the code in effect at the time of installation? (1/19/2005)
The code in effect at the time of filing takes precedence. See Sections 300.1(B) and 110.2. The Calendar Number may still be valid, unless the code requirements affecting the product have changed.
- We are using #4 AWG (85 Amps) wires for the feeders to a series of apartments. Can the current carrying capacity of the wires exceed 85 Amps if 100 Amp HACR magnetic type breakers are used? (7/6/2005)
Yes, for 120/240 V, as per Section 310.15(B)(6).
No, for all other applications.
Section 348.20(A) & 320.30(D)(3)
- Is it permissible to use exposed 3/8 inch Flexible Metal Conduit (Greenfield) with #12 THHN conductors or 12/2 Armored Cable (BX) with THHN conductors for the installation of suspended track lighting? (2/9/2005)
No for Flexible Metal Conduit, see Section 348.20(A). Yes for Armored Cable, see Section 320.30(D)(3).
- Is the newly added subsection 352.10(I) intended to limit the use of RNC to three (3) story buildings?
The RNC may be installed in accordance with the requirements of the amended Section 362.10.
- Does subsection 352.10(A) allow the use of RNC in four (4) story or taller residential buildings, as long as it is concealed in slabs, walls, or ceilings?
Yes, subject to the inspection requirements of Article 362, as amended.
- Does the newly added subsection 352.12(G) allow the use of RNC in office towers taller than three (3) stories.
- Can ENT be installed in four (4) story or taller residential buildings, as long as it is concealed and meets the requirements of subsection 362.10.2? (10/19/2005)
Yes, subject to the requirements of the amended Section 362.10.
Chapter 4: Equipment for General Use (Code Section 400-1 to 490-74)
- For surface mounted luminaires that are through fed, what is the maximum allowed length of conduit between luminaires without an outlet? (2/9/2005)
No limitations are imposed. See Section 410.32
Section 422.31(B) & 422.34
- In a residential building, the individual apartments have electric ranges that are not within eyesight of the electrical panel. Is it permissible to hardwire the ranges without a local disconnect means? (10/19/2005)
The installation of the electric ranges shall be in accordance with Section 422.31(B) or 422.34.
- How many disconnect switches may be installed on an emergency generator? (10/19/2005)
Unlimited disconnecting means may be installed. See Section 445.18.
Section 445.18 & 250.30
- Is it permissible to install a service switch near an outdoor generator of a non-utility supplied commercial, single occupancy building? The service switch is located in a yard that is not accessible to the public.
Yes, the generator switch shall be in accordance with Section 445.18. This switch is not a service switch.
- In the above situation, in series with the outdoor switch there is another disconnect switch inside the building. Should the grounding electrode be connected to the inside or the outside service switch? (10/19/2005)
The grounding electrode shall be connected to the inside disconnect switch. If required, see Section 250.30.
Chapter 5: Special Occupancies (Code Section 500-1 to 555-11)
- Are doctor's, dentist's and chiropractor's treatment rooms considered health care facilities covered under Article 517? (6/8/2005)
Yes. See Section 517.10.
- We are performing electrical work in a hospital cardiac catheterization lab. The work includes the installation of a catheterization machine, lighting and receptacles. Section 517.30(B)(3) of the NEC requires that major electrical equipment be supplied by the Equipment Power System, and Section 517.33(A)(8) requires that task illumination, selected receptacles and selected power circuits be supplied by the Critical Branch of the Emergency System. Should the machine be connected to the Equipment System or to the Critical Branch of the Emergency System? (4/6/2005)
The catheterization machine should be connected to the Critical Branch of the Emergency System as per Section 517.33(A)(8)c.
Chapter 6: Special Equipment (Code Section 600-1 to 695-14)
- Regarding amended Section 604.1(A)1, do manufactured wiring systems that are UL listed:
- Require NYC Advisory Board approval?
Yes. Consult the Advisory Board rules.
- Require an MEA number or an Advisory Board Calendar Number?
The MEA number is not an Electrical Code requirement. However, a calendar number is required, which is provided by the Advisory Board. See Section 110.2.
- Regarding amended Section 604.1(A)6, we intend to use a manufactured wiring system above a hung ceiling whose grid was left open (no tiles).
- Does the open ceiling grid qualify as a hung ceiling and if so, can the bottom face be considered the ceiling line?
- Can the wiring system be connected to non-emergency lighting and floor mounted displays? (12/7/2005)
- When sizing a feeder for the supply of multiple motors and other loads as stated in NEC Article 430-24, the conductor sizing is based on 125% of the largest single
motor plus the sum of the full load current rating of the remaining motors. When the rating of this feeder based upon this calculation method exceed 800 Amperes, does the overcurrent protective device get sized based upon Article 430.62 which utilizes Table 430.52, or does Article 240.4(C) apply which states that "Where the overcurrent device is rated over 800 Amperes the ampacity of the conductors it protects shall be equal to or greater than the rating of the overcurrent device"? Our installation consists of a single feeder service a distribution panelboard located within an elevator machine room that serves 6 elevator motors, 2 air handling motors and a 15 KVA transformer for incidental loads and control circuits associated with the elevator equipment. The elevator motors are fixed and no additional loads are served by this panelboard. Each of the 6 elevator motors are individually protected with an overcurrent device within the panelboard as are the air handler motors and transformer. All motors are also provided with separate overload protection on their respective controllers. Using Article 430.24 for calculating the required ampacity of the feeder, our calculations yield a required ampacity of approximately 1200 Amperes. We are installing feeder, our calculations yield a required ampacity of approximately 1200 Amperes. We are installing and Table 430.52, the rating of our overcurrent device for this specific feeder is 1600 Amperes. Please indicate whether we have correctly interpreted the method for sizing the feeder conductor and overcurrent device. (2/9/2005)
See Section 620.13 for sizing of the elevator motor feeder and of the overcurrent protection device.
- An existing DC elevator is being converted to AC. The elevator machine room lights are also DC. Is it permissible to run the branch circuit(s) conduit for the lights, up the elevator shaft to the elevator machine room? (10/19/2005)
No. See Section 620.37(A).
- Is it permissible to run through an elevator machine room an electrical conduit (without any junction boxes) that is not associated with the elevator operation? (10/19/2005)
- New York City has amended Section 620.51(A) by deleting the word "fused" in front of "motor circuit switch".
- Does it mean that "not fused" disconnect switches shall be provided in the elevator machinery room?
Unfused disconnecting means are permitted where other overcurrent protective devices are provided to properly protect the elevator circuit.
- Does this section apply to all elevators, including multiple elevators with one machinery room and connected to the same feeder?
For multiple elevators connected to the same feeder. Each elevator circuit must be properly protected.
- If the answer to a. & b. above is YES, how should the elevator motor control wiring be protected, especially solid state motor controls such as SCR, VVVF or hydraulic pump type systems? (7/6/2005)
See a. above.
- Are the requirements of Article 645 optional, when a wiring system is designed in accordance with the other Chapters?
The requirements of Article 645 are applicable when conditions described in the Article exist.
- If not optional, does Article 645 apply to telephone/data rooms located on every floor of a building?
See a. above.
- Are the fine print notes (FPN's) in the NEC used for information purposes only, and therefore not enforceable? (4/6/2005)
- In reading the amended Section 695.3(A)(1) it appears that the service switch for a fire pump can be part of the switchboard line-up, providing that it occupies a dedicated cubicle, separated by barriers from the adjacent switchboard cubicles. In other words, the fire pump service switch does not necessarily have to be a stand-alone switch totally separated from the service switchboard. Is our interpretation correct? (6/8/2005)
The present code does not strictly prohibit such an installation. The 2007 New York City Electrical Code most likely will.
- A generator feeds a distribution board through a fused disconnect. A fused switch in the emergency distribution board then feeds a fire pump. Assuming that both sets of fuses are properly sized, is it permissible for the fire pump to have secondary fusing? (1/19/2005)
No. See amended Section 695.3(B)(1).
- A 200 HP DC fire pump is supplied via a AC/DC rectifier from a 208V switchboard overcurrent device. Is an over-current device also required on the load side of the rectifier? (2/9/2005)
Not permitted. See Section 695.4.
- We intend to install a special service fire pump (as defined by the New York City Building Code RS-17, 2-5) in an existing 20 stories office building. The pump will draw from the existing combination tank's fire reserve and serve the new sprinkler systems on the upper floors of the building. The following design is being considered:
We request interpretation of the following questions:
- The new pump is to be located above the ground floor and will not exceed 30 HP. (The actual pump size will be 15 HP).
- The building does not have an emergency generator.
- A new service switch will be connected on the utility side of the existing main service switches and will be sized to accommodate an overcurrent protection of 600% of the pump motor's FLA.
- A new feeder will be installed, from the new service switch in the basement to the new pump controller located on the penthouse (21st) floor.
- The new feeder will be a THHN cable installed in EMT and located in an existing stairway. The metallic conduit will not be enclosed in a 1-hour rated enclosure.
- The feeders will be sized at 125% of the FLA (NEC 2002, 695.6 (C)), with a calculated voltage drop not to exceed 5% at 115% of the FLA, and a voltage drop at startup (LRA) of not more than 15%. (NEC 2002695.7).
- Is the installation as described above code compliant?
See the following.
- For special service fire pumps, is any metallic raceway permissible?
EMT, IMC, and RMC are OK.
- Is rigid conduit required?
- Can the feeder for pump be installed in a fire stairway?
No. See the NYC Building Code.
- Can the size of the overcurrent device be decreased to 150% FLA?
- Can the feeder be installed without a fire rated enclosure and/or fire rating?
- Does the voltage drop limitation for motor startup mentioned above (NEC 2002 695.7) apply to special service pumps?
- Must the fire pump and power source be monitored by a central fire alarm system?
Yes. See the amended Section 695.4.
- If there is an existing empty conduit available within the building may we use it in lieu of installing a new conduit?
Yes, if it meets all the code requirements.
- Can this pump be connected to the local power in lieu of a feeder fed from a service switch? (1/19/2005)
No, unless an alternate source is available.
Chapter 7: Special Conditions (Code Section 700-1 to 780-7)
- Does Section 700.12 apply only to emergency systems legally required and as such only to systems and building occupancies listed in Section 27-396.4 and Rule 12.01 of the Building Code (BC)? (1/19/2005)
No. Section 700.1 of the New York City Electrical Code applies.
- Section 27-542 of the BC - "Emergency Lighting" for spaces of Assembly (F-1a, F-1b, F-2, F-3, and F-4) permits the connection of emergency lighting ahead of the main switch. Since Assembly occupancies are not listed among the occupancies in Section 27-396.4 that legally require emergency systems under the Building Code, is the connection of emergency lighting ahead of the main switch in these occupancies in compliance with NYC Codes and Regulations? (1/19/2005)
No. See Section 700.1 of the New York City Electrical Code.
Chapter 8: Communications Systems (Code Section 800-1 to 830-58)
- Local Law 41 of 2002 had references to electric closets in Sections 800-52(f) and 830-3(e). These references are now missing from Local Law 81 of 2003. Has there been a change in policy? If not, please recommend a way of confirming to a questioning contractor that this reference is still applicable.
There is no change in policy. Please use this letter as confirmation of applicability.
- Section 830-3(e) of Local Law 41 of 2002 refers to "Network powered broadband communications equipment". What does "network power" refer to? (10/19/2005)
Refer to Section 830.2.
Articles: A subdivision of a Chapter, comprised of a certain number of Sections
- The old New York City Electrical Code used to require concrete encasement for all wiring with voltages exceeding 7.5 KV to ground, when run inside a building. The NEC did not and does not have such a requirement.
- Has this requirement now been lifted for New York City?
Service conductors shall be installed in accordance with Article 230.
- Can 13.2 KV feeders run in conduit only through the building? (10/19/2005)
Protected feeder conductors, may be installed without encasement, up to 13.8 KV. Such installations require Advisory Board submission and approval.
- A 1.5 inch PVC conduit would be buried in concrete and used later as a tunnel for running cables. Is this permissible? (12/7/2005)
Yes. If the PVC conduit is used as a wiring raceway, it shall be installed in accordance with Article 352 and other applicable Articles.
- At an existing hospital we would like to connect a Catheterization Machine to an emergency switchboard that serves emergency lighting, power and mechanical equipment. The board is simply labeled "Emergency Switchboard". There is no time delay on the automatic transfer switch serving the board. Would the connection to this board meet the intent of the Code? (6/8/2005)
Such an application does not meet the intent of the current code. However, special permission may be requested. See Article 517.
- Can natural gas be used as a fuel source for optional stand-by genertors? (7/6/2005)
Optional stand-by installations are acceptable, as per Article 702. Other jurisdictions apply.
- An engineer is proposing a broadband cellular / PCS distributed antenna system (DAS), which consists of a central base unit that is connected to remote units on each floor via a fiber optic riser. The fiber optic riser is an interlocked armored composite cable assembly. The remote units will be powered by Class 1 power supplies, connected to the central point via 2 # 14AWG conductors that are part of the composite cable assembly. Is it permissible to use a composite interlocked armored cable assembly for this application, which complies with Article 770? (6/8/2005)
Class 1 wiring must comply with the requirements of Section II of Article 725. Also, see Article 830.
Administrative: General Requirements
- Which of the following formulas should be used to calculate the voltage drop for an apartment building riser?
The voltage drop calculations must be based on the appropriate system characteristics.
- AC Formula: Vd=V +IRcosθ + IXsinθ - V V² - (IXcosθ - IRsinθ)²
- Modified DC formula: Vd = (2 x K x L x I) / CM
- DC Formula: Vd = (2 x R x L x I) / 1000 (12/7/05)
- Is it permissible to use transformer taps to adjust for voltage drop conditions on long feeders? (12/7/05)
No. Voltage drop calculations are based on design load conditions to achieve the required voltage at the load. Using fixed transformer taps to meet voltage requirements, under design load conditions, will result in overvoltage conditions at the load under low load conditions.
- We are installing an under-carpet wiring system in a public library. The flat cable extends from the public area all the way into the electrical closet. Is it permissible to extend the carpeting into the electrical closet? (10/19/05)
The electrical code does not prohibit the use of carpeting in an electrical closet. However, other jurisdictions apply. Individual installation details must be submitted to the Advisory Board for approval.
- Is it permissible to use liquidtight flexible nonmetallic conduit as a raceway for the infeed connection between an electrified furniture partition and a wall or floor mounted junction box? If so, what is the maximum length allowed? (9/7/05)
- Is it permissible to remove the internal parts of an existing fuse box and replace them with the internal parts of a new circuit breaker panel? If not, is special approval required on a case by case bases? (9/7/2005)
No. Advisory Board approval is required on a case by case bases.
- A 75 KW rectifier is being installed in the basement of a building. The DC loads include a fire pump, fused at 150A.
- How should the rectifier feeder fuse be sized: at 125% of the rectifier FLA or at 600% of fire pump load plus 100% of elevator load?
The service switch must be rated at 600% of fire pump load plus 100% of the other loads. The rectifier and the line side feeder must be rated at 125% of the full load amps, and they must be capable of handling motor starting current characteristics.
- Since the rectifier is not located within the line-of-sight from its supply switch, should an additional local non-fusible disconnect switch be provided? (4/6/2005)
- We are in the process of designing a 10-family residential apartment building in which all the utility rooms are aligned in tandem. To enter the Electrical Service Room, one must pass through the Gas Service Room and then the Water Service Room. Exiting the Electrical Service Room, therefore, must be through the Water Room and then through the Gas Service Room. A clear path to exit will exist in each room. Is this layout permissible? (4/6/2005)
For services less than 1000KVA, the locations of the utility rooms are acceptable as per the described configuration. The electrical equipment must remain accessible.
- The New York State Energy Code, Section 102.6 requires that "In all buildings having individual dwelling units, provisions shall be made to determine the electrical energy consumed by each tenant by separately metering individual dwelling units". Does this requirement apply to college dormitories that are classified as J-2 occupancies? (6/8/2005)
This question would be properly addressed by the New York State Department of State, 41 State Street, Albany, NY 12231. We recommend contracting Mr. Steve Rocklin, at 518-478-4073.
- Diverted Con Ed Service: A new extension is being added to a Brooklyn museum. The existing 1500 Amp, 120/208V service that serves the existing building must be diverted because the new addition is in the path of the secondary Con Edison service feeders exiting the below grade crab compartment. A unique solution was worked out with Con Edison: a temporary above grade outdoor service end box / switch, in a watertight shed, will be installed adjacent to the crab compartment that will allow the existing service feeders to be verted to the end box (provided with Con Edison limiter lugs) and then serve the switch fused at 1500 amps.
This installation does not require an outdoor switch. However, if such a switch is utilized, special permission would be required.
- Is the above grade outdoor switch considered to be a service switch?
- Is the switch required to be grounded with the neutral bonded to the ground and switch enclosure, and have a ground rod driven into the earth at the switch with an equipment ground run in each set to the existing indoor service switchboard?
- Can the conductors at the load side of the switch be THWN type, installed in fiberglass reinforced epoxy conduit buried 12" below grade?
- Would mineral insulated cable be acceptable at the load side of the switch in lieu of THWN conductors in FRE conduits?
- Is it acceptable to have NEMA 1 construction in an outdoor watertight shed? (5/4/2005)
- Maintenance Work: Are Unlicensed Maintenance Workers and Operating Engineers (Stationary Engineers), not covered under the license of a Master or Special Electrician, allowed to perform the following work:
- Remove Panel Trims or covers, exposing live wiring and connections.
- Replace fuses in Electrical Service Equipment.
- Take amperage or voltage measurements with hand held devices.
No, see a. above .
- Replace low voltage electric thermostats.
- Modify low voltage control wiring.
- Install temporary metering devices.
No, see a. above.
- Run telephone/communication wiring. (5/4/2005)
May be performed by a low voltage installer. See Section 27-3004 of the Administrative Code.
- Custom Built Luminaire: We were asked to manufacture a custom built light fixture that will clip into an opening in the side of a wooden armoire. The fixture is entirely portable and the installation/removal require no tools. The power is supplied via a six-foot cordset that passes througha hole in the back of the armoire. The fixture will be tested and listed by the UL. Will the fixture be in compliance with the
NYC codes? (5/4/2005)
The assembly including the light fixture is acceptable, as long as the fixture is listed as portable.
- Local Law 26 requires that a battery pack be provided, as back-up power, for all existing illuminated exit signs. Is the use of wireless controls, or of power line carriers, acceptable methods for activating the battery packs, in lieu of dedicated hard-wired controls? (2/9/2005)
Any design using the described systems requires the approval of the Advisory Board and of other jurisdictions.
The NYC 2011 Electrical Code – Administrative Provisions and 2008 NEC Amendments is now on sale on the CityStore.
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