The top 25 revisions to this edition of the NEC
Has it already been three years? For some of you who wait with bated breath for every edition of the National Electrical Code, the 2005 NEC probably couldn't have come soon enough. For the rest of you who were just getting used to the 2002 edition, though, it no doubt seems like just yesterday that the NEC underwent a massive renumbering effort and AFCIs became a requirement for all 125V bedroom outlets.
But it's not like you didn't know it was coming. And just as predictable as the arrival of each new edition of the NEC is, so is EC&M's coverage of the changes most likely to affect you. This time we're mixing things up a bit. Instead of bogging you down with countless minute changes that might never rear their heads in your work in the field, we've enlisted Mike Holt to narrow the field to the Top 25 need-to-know revisions, as excerpted from his book, Mike Holt's Illustrated Guide — Changes to the NEC 2005. Regardless of what you do or where you work, these are the changes that are sure to pop up sooner or later. But because everyone's job is different and no two people will be affected the same, we're skipping a subjective ranking of all 25 and presenting them in the order they appear in the 2005 NEC. And for those of you in jurisdictions still using the 1996 or 1999 Code, well, consider the following a preview of what you have to look forward to in nine years or so.
As you read through this analysis, you'll notice we've used several different type faces. Blue text is a slightly reworded representation of what appears in the Code. Underlined blue text represents Code text that has either been changed or added.
And because we know you can't get enough Code change info, we'll be highlighting one additional change not listed here in each issue of our e-mail newsletter dedicated to the NEC, CodeWatch, beginning on Dec. 8 and continuing throughout 2005. Don't receive CodeWatch? Visit www.ecmweb.com and click on “subscriptions” to sign up.
#1. 210.8 GFCI PROTECTION
The text was revised to require all 15A and 20A, 125V receptacles within 6 feet of the dwelling unit laundry or utility sink to be GFCI protected. Irons, hair dryers, and similar items with ungrounded polarized and nonpolarized cord caps are commonly used in this area and present the same shock hazard found in other areas where the NEC currently requires GFCI protection.
(A) Dwelling Units
(7) Laundry, Utility, and Wet Bar Sinks. GFCI protection is required for all 15 and 20A, 125V receptacles located within an arc measurement of 6 ft from the dwelling unit laundry, utility, and wet bar sink. (Fig. 1 )
#2. 210.8 GFCI PROTECTION
The GFCI protection requirement for commercial kitchens was clarified by adding a definition of a kitchen. This new requirement expands the GFCI protection requirements for 15A or 20A, 125V receptacles to include receptacles that are located outdoors and accessible to the public.
(B) Other Than Dwelling Units
(2) Commercial and Institutional Kitchens. All 15 and 20A, 125V receptacles installed in kitchens, even those that do not supply the countertop surface, must be GFCI protected.
Author's Comment: GFCI protection is required for all 15A and 20A, 125V receptacles installed in kitchens, even if not readily accessible or on a dedicated branch circuit for a specific cord-and-plug connected appliance. (Fig. 2)
For the purposes of this section, a kitchen is defined as an area with a sink and permanent facilities for food preparation and cooking.
Author's Comment: This definition distinguishes commercial and institutional kitchens from those areas often found in employee break rooms that might have a portable cooking appliance.
#3. 210.8 GFCI PROTECTION
New text was added that calls for the installation of GFCI-protected receptacles in all outdoor public spaces accessible to the public.
(4) Outdoor Public Spaces. All 15 and 20A, 125V receptacles installed in a public space that is for use by or is accessible to the public must be GFCI protected. (Fig. 3)
Ex: GFCI protection isn't required for a fixed electric snow-melting or de-icing equipment receptacle that isn't readily accessible. See 426.28.
Author's Comment: GFCI protection isn't required for receptacles located outside of commercial and industrial occupancies where the general public doesn't have access. (Fig. 4)
#4. 210.12 ARC-FAULT CIRCUIT-INTERRUPTER PROTECTION
Text was revised to require that all dwelling unit bedroom branch-circuit AFCI protection devices must be listed as a “Combination Type AFCI,” effective Jan. 1, 2008. And a new exception permits AFCI protection by a device that isn't a circuit breaker, such as a receptacle, but only if it meets stringent requirements.
(B) Dwelling Unit Bedroom Circuits. All 15 or 20A, 120V branch circuits that supply outlets in dwelling unit bedrooms must be AFCI-protected by a listed arc-fault circuit interrupter. (Fig. 5)
Author's Comment: Smoke detectors connected to a 15A or 20A circuit must be AFCI-protected if the smoke detector is located in the bedroom of a dwelling unit. The exemption of AFCI protection for the fire alarm circuit (760.21 and 760.41) doesn't apply to the smoke detector circuit, because a smoke detector circuit isn't defined as a fire alarm circuit; it's an “alarm circuit” (See NFPA 72, National Fire Alarm Code).
After January 1, 2008 (basically a 2008 NEC requirement), AFCI protection shall be provided by a combination type AFCI protection device.
Author's Comment: Combination type AFCI protection devices provide improved safety performance over existing AFCI protection devices, because the combination type is designed to detect arcs as low as 5A peak. Existing branch-circuit AFCI circuit breakers are designed to operate when the arcs exceeds 75A peak.
See UL 1699, Standard for Arc-Fault Circuit Interrupters (www.UL.com) for information on the differences between a branch-circuit type AFCI and a combination type AFCI.
Ex: The location of the AFCI can be at other than the origination of the branch circuit if in compliance with (a) and (b).
(a) The AFCI is installed within 6 ft of the branch-circuit overcurrent device as measured along the branch-circuit conductors.
(b) The circuit conductors between the branch-circuit overcurrent device and the AFCI must be installed in a metal raceway or a cable with a metallic sheath.
Author's Comment: The 120V circuit limitation means that AFCI protection isn't required for equipment rated 230V, such as a baseboard heater or room air-conditioner.
#5. 250.104 BONDING OF PIPING SYSTEMS AND EXPOSED STRUCTURAL METAL
The structural metal member bonding requirements that were located in 250.30(A)(3)(d) and 250.104(A)(1) were combined and relocated to 250.104(D) to improve NEC usability.
(D) Separately Derived Systems. Metal water pipe systems and structural metal that is interconnected to form a building frame must be bonded to the separately derived systems in accordance with (1), (2) and (3).
(1) In the area served by a separately derived system the nearest available point of the metal water piping system must be bonded to the grounded (neutral) terminal of the separately derived system. The bonding at the separately derived system must be at the same location where the grounding electrode conductor and system jumper terminates [250.32(A)]. (Fig. 6)
The bonding jumper for the metal water pipe system must be sized in accordance with Table 250.66, based on the largest ungrounded conductor of the separately derived system.
Ex. 1: A bonding jumper from the metal water piping system to the separately derived system isn't required if the water pipe is used as the grounding (earthing) electrode for the separately derived system.
Ex. 2: A separate bonding jumper to the metal water pipe isn't required where the metal frame of the building or structure is used as the grounding (earthing) electrode for a separately derived system and is bonded to the metal water pipe in the area served by the separately derived system. (Fig. 7)
(2) Structural Metal. Where exposed structural metal that is interconnected to form the building frame exists in the area served by the separately derived system, it must be bonded to the grounded (neutral) conductor of each separately derived system. This connection must be made at the same point on the separately derived system where the grounding electrode conductor is connected. Each bonding jumper must be sized in accordance with Table 250.66 based on the largest ungrounded conductor of the separately derived system.
Ex 1: A separate bonding jumper to the building structural metal isn't required where the metal frame of a building or structure is used as the grounding electrode for the separately derived system.
Ex 2: A separate bonding jumper to the building structural metal isn't required where the water piping of a building or structure is used as the grounding electrode for a separately derived system and is bonded to the building structural metal in the area served by the separately derived system.
(3) Common Grounding Electrode Conductor. Where a common grounding electrode conductor is installed for multiple separately derived systems as permitted by 250.30(A)(4), and exposed structural metal that is interconnected to form the building frame or interior metal piping exists in the area served by the separately derived system, the metal piping and the structural metal member must be bonded to the common grounding electrode conductor.
Ex: A separate bonding jumper from each derived system to metal water piping and to structural metal members isn't required where the metal water piping and the structural metal members in the area served by the separately derived system are bonded to the common grounding electrode conductor.
#6. 250.2 DEFINITIONS
The text added to the definition of an effective ground-fault current path is intended to help the Code user understand that its purpose is to help clear a ground fault by facilitating the operation of the overcurrent device.
Effective Ground-Fault Current Path. An intentionally constructed, permanent, low-impedance conductive path designed to carry fault current from the point of a ground fault on a wiring system to the grounded (neutral) point at the electrical supply source. (Fig. 8)
The effective ground-fault current path is intended to facilitate the operation of the circuit overcurrent protective device, or the ground-fault detector on a high-impedance grounded system. (Fig. 9)
#7. 250.4 GENERAL REQUIREMENTS FOR GROUNDING AND BONDING
This change clarifies that swift operation of an overcurrent protection device in the presence of a ground fault depends upon the existence of an effective ground-fault current path from the point of the fault to the power supply neutral.
The last sentence was revised to make it clear that the earth can't be used as the effective ground-fault current path. It won't facilitate the opening of the circuit protection device from a ground fault.
(A) Solidly-Grounded Systems.
(5) Effective Ground-Fault Current Path. Electrical raceways, cables, enclosures, and equipment, as well as other electrically conductive material that are “likely to become energized,” must be installed in a manner that creates a permanent, low-impedance path that facilitates the operation of the circuit overcurrent device or ground-fault detector for high-impedance grounded systems. (Fig. 10 above right)
The effective ground-fault current path must be capable of safely carrying the maximum fault current likely to be imposed on it from any point on the wiring system where a ground fault may occur to the electrical supply source neutral (110.10).
Author's Comment: Clearing ground faults (line-to-case faults) is accomplished by bonding all metal parts of electrical equipment and conductive material likely to become energized to the power-supply grounded (neutral) terminal.
Another factor necessary to help ensure an effective ground-fault current path is that all circuit conductors [ungrounded, grounded and the equipment grounding (bonding) conductor] must be grouped together in the same raceway, cable, or trench [300.3(B), 300.5(I), and 300.20(A)]. (Fig. 11 above)
The earth isn't considered an effective ground-fault current path. (Fig. 12)
#8. 250.50 GROUNDING ELECTRODE SYSTEM
The words “if available” have been replaced with “are present.” The effect is that a concrete-encased electrode (Ufer) is always required for new construction, because it is present. However, a new exception adds clarity that a concrete-encased electrode [250.52(A)(3)] isn't required for existing buildings or structures.
All grounding electrodes as described in 250.52(A)(1) through (A)(6) that are present at each building or structure must be bonded together to form the grounding electrode system. (Fig. 13)
Ex: Concrete-encased electrodes are not required for existing buildings or structures where the conductive steel reinforcing bars aren't accessible without disturbing the concrete.
#9. 250.52 GROUNDING ELECTRODES
The language in the 2002 NEC was vague and subject to wide interpretation as it described when the metal frame of a building or structure could serve as a grounding electrode. The new text establishes the requirement for the structural metal electrode. In addition, listed galvanized rods of the 0.5-inch diameter are now permitted.
(A) Electrodes Permitted for Grounding.
(2) Metal Frame of the Building or Structure Electrode. The metal frame of the building or structure can serve as a grounding electrode, where any of the following methods exist:
(a) 10 ft or more of a single structural metal member is in direct contact with the earth or encased in concrete that is in direct contact with the earth
(b) The structural metal is bonded to an electrode as defined in 250.52(A)(1), (3), or (4)
(c) The structural metal is bonded to two ground rods if the ground resistance of a single ground rod exceeds 25 ohms [250.52(A)(5) and 250.56]
(d) Other means approved by the authority having jurisdiction
Author's Comment: The intent is that the metal used in the building structure be of substantial cross-sectional area (“I” beams, columns, channel, and angle iron). It doesn't include items like sheet metal studs that are made of much thinner metal.
The grounding electrode conductor to the metal frame of a building or structure must be sized in accordance with Table 250.66. (Fig. 14)
#10. 250.52 GROUNDING ELECTRODES
(5) Ground Rod Electrodes. Ground rod electrodes must not be less than 8 ft long and must have not less than 8 ft of length in contact with the soil [250.53(G)].
(a) Electrodes of pipe or conduit must not be smaller than 3/4 inch and, where of iron or steel, must have the outer surface galvanized or otherwise metal-coated for corrosion protection.
(b) Rod. Unlisted ground rod must have a diameter of at least 5/8 in., whereas listed ground rods only require a diameter of 1/2 in.
#11. 310.10 INSULATION TEMPERATURE LIMITATION
A new FPN alerts the designer to consider elevated ambient temperatures when raceways are installed outdoors in direct sunlight in close proximity to rooftops.
Conductors cannot be used where the operating temperature exceeds that designated for the type of insulated conductor involved.
FPN No. 2: Conductors installed in conduit exposed to direct sunlight in close proximity to rooftops have been shown, under certain conditions, to experience an increase in temperature of 30°F above ambient temperature. (Fig. 15)
Author's Comment: A Fine Print Note (FPN) is for information only and isn't intended to be enforceable [90.5(C)].
#12. 314.30 HANDHOLE ENCLOSURES
This new section contains the requirements for handhole enclosures.
Handhole enclosures must be designed and installed to withstand all loads likely to be imposed.
FPN: See ANSI/SCTE 77, Specification for Underground Enclosure Integrity, for additional information on deliberate and nondeliberate traffic loading that can be expected to bear on underground enclosures.
(A) Size. Handhole enclosures must be sized in accordance with 314.28(A). For handhole enclosures without bottoms, the measurement to the removable cover is taken from the end of the conduit or cable assembly.
(B) Mechanical Connection. Underground raceways and cable entering a handhole enclosure aren't required to be mechanically connected to the handhole enclosure. (Fig. 16)
(C) Handhole Enclosures Without Bottoms. All splices or terminations must be listed as suitable for wet locations.
(D) Covers. Handhole enclosure covers must have an identifying mark or logo that prominently identifies the function of the enclosure, such as “electric.”
Handhole enclosure covers must require the use of tools to open, or they must weigh over 100 lb. Metal covers and other exposed conductive surfaces must be bonded to an effective ground fault current path in accordance with 250.96(A) [250.4(A)(3)].
#13. 400.14 PROTECTION FROM DAMAGE
This new paragraph permits flexible cords to be installed in aboveground raceways in industrial environments in lengths up to 50 feet, but only under restricted conditions.
Flexible cords must be protected by bushings or fittings where passing through holes in covers, outlet boxes, or similar enclosures.
In industrial establishments where the conditions of maintenance and supervision ensure that only qualified persons will service the installation, flexible cords not exceeding 50 ft can be installed in above ground raceways.
#14. 406.8 RECEPTACLES IN DAMP OR WET LOCATIONS
The wording has been revised to clarify where a receptacle isn't permitted in a bathroom.
(C) Bathtub and Shower Space. Receptacles must not be installed within or directly over a bathtub or shower stall. (Fig. 17)
Author's Comment: Receptacles must be located no less than 5 feet from any spa or hot tub [680.21(A)(1) and 680.43(A)(1)].
#15. 410.73 GENERAL
This new rule specifies when luminaires with metal halide lamps are to be provided with a method to help contain the arc at end-of-life arc-tube failures.
(F) High-Intensity Discharge Luminaires.
(5) Metal Halide Lamp Containment. Luminaires containing metal halide lamps, other than a thick-glass parabolic reflector lamp (PAR), must be provided with a containment barrier that encloses the lamp or the luminaire must only allow the use of a Type “O” lamp. (Fig. 18)
Author's Comment: Fires have resulted from the spillage of hot arc-tube particles from metal halide lamp failures. “O-rated” lamps have been designed to meet the ANSI containment test for the installation of the metal halide lamp in an open fixture.
#16. 410.73 GENERAL
This rule was added to require disconnecting means for fluorescent luminaires that have double-ended lamps and contain ballasts. However, it isn't effective until Jan. 1, 2008.
(G) Disconnecting Means. In indoor locations, other than dwellings and associated accessory structures, fluorescent luminaires that utilize double-ended lamps and contain ballast(s) that can be serviced in place or re-ballasted must have a disconnecting means, to disconnect simultaneously all conductors of the ballast, including the grounded (neutral) conductor if any. The disconnecting means must be accessible to qualified persons. This requirement will become effective January 1, 2008 (Basically a 2008 NEC requirement).
Author's Comment: Changing the ballast out while the circuit feeding the luminaire is energized has become a regular practice, because a local disconnect isn't available. Also, ballasts are often serviced from a ladder, adding the possibility of increased injury from a fall. The rule requires the disconnecting means to open “all circuit conductors,” including the grounded (neutral) conductor. If the grounded (neutral) conductor in a multiwire circuit isn't disconnected at the same time as the ungrounded conductor, a false sense of security could result in an unexpected shock, and its consequences from the grounded (neutral) conductor.
Ex 1: A disconnecting means isn't required for luminaires installed in hazardous (classified) location(s).
Ex 2: A disconnecting means isn't required for emergency illumination required in 700.16.
Ex 3: For cord-and-plug-connected luminaires, an accessible separable connector or an accessible plug and receptacle is permitted to serve as the disconnecting means.
Ex 4: A disconnecting means isn't required in industrial establishments with restricted public access where written procedures and conditions of maintenance and supervision ensure that only qualified persons service the installation.
Ex 5: Where more than one luminaire is installed and supplied by other than a multiwire branch circuit, a disconnecting means isn't required for every luminaire when the design of the installation includes locally accessible disconnects, such that the illuminated space won't be left in total darkness
#17. 422.51 CORD-AND-PLUG-CONNECTED VENDING MACHINES
Because of three recent deaths, a new Code section requires GFCI protection for cord-and-plug-connected vending machines.
Cord-and-plug-connected vending machines manufactured or re-manufactured on or after January 1, 2005 must include a ground-fault circuit interrupter as an integral part of the attachment plug. Cord-and-plug-connected vending machines not incorporating integral GFCI protection must be connected to a GFCI-protected outlet.
Author's Comment: This change was driven by three electrocutions since 1995; two of the victims were children who touched the energized metal parts of a vending machine. Because electric vending machines are often located in damp or wet locations in public places, and are used by people standing on the ground, reliance on an equipment grounding (bonding) conductor for protection against electrocution is insufficient.
#18. 513.12 GFCI-PROTECTED RECEPTACLES
This new section requires GFCI protection for 15A and 20A, 125V receptacles where aircraft might undergo service, repairs, or alterations.
GFCI protection for personnel is required for all 15 and 20A, 125V receptacles used for service and repair operations, such as electrical diagnostic equipment, electrical hand-tools, portable lighting devices, etc. (Fig. 19)
Author's Comment: Personnel who service and maintain aircraft use the same hand tools and equipment that are used in commercial garages, which requires GFCI protection.
#19. 680.26 EQUIPOTENTIAL BONDING
The term “equipotential bonding” was added to the title to clarify that the purpose of bonding is to reduce electric shock from stray voltage.
And a Fine Print Note was converted into a Code requirement to specify that “equipotential bonding conductors aren't required to extend to any panelboard, service equipment, or an electrode.”
(A) Performance. Equipotential bonding is intended to reduce or eliminate voltage gradients from stray voltage in the permanently installed pool, outdoor spa, and outdoor hot tub area by forming a common bonding grid.
Author's Comment: Equipotential bonding isn't intended to provide a low-impedance ground-fault current path to help assist in clearing a ground fault.
The 8 AWG or larger solid copper equipotential bonding conductor [680.26(C)] isn't required to be extended to or attached to any panelboard, service equipment, or an electrode.
#20. 680.26 EQUIPOTENTIAL BONDING
This change requires an equipotential bonding grid to be installed to reduce voltage gradients in and around permanently installed pools, outdoor spas, and outdoor hot tubs.
(B) Bonded Parts. The following parts of a permanently installed pool, outdoor spa, and outdoor hot tub must be bonded to a equipotential bonding grid of the type specified in 680.26(C).
Author's Comment: See 680.42(B) for the bonding methods permitted for outdoor spas and hot tubs.
(1) Metallic Parts of Structure. All metallic parts of the water structure, including the reinforcing metal of the permanently installed pool, outdoor spa, and outdoor hot tub shell and deck, must be bonded to the equipotential grid. The usual steel tie wires are considered suitable for bonding the reinforcing steel together for this purpose. Welding or special clamping is not required, but the tie wires must be made tight. (Fig. 20)
Where the reinforcing steel of the permanently installed pool, outdoor spa, and outdoor hot tub shell and deck are encapsulated with a nonconductive compound or if it's not available, an equipotential grid constructed in accordance with 680.26(C) must be installed to mask stray voltage gradients.
(2) Underwater Lighting. All metal forming shells for underwater permanently installed pool, outdoor spa, and outdoor hot tub luminaires and speakers.
(3) Metal Fittings. Metal fittings within or attached to the permanently installed pool, outdoor spa, and outdoor hot tub structure, such as ladders and handrails.
(4) Electrical Equipment. Metal parts of electrical equipment associated with the permanently installed pool, outdoor spa, and outdoor hot tub water circulating system, such as water heaters and pump motors. Accessible metal parts of listed equipment incorporating a system of double insulation and providing a means for grounding internal metal parts are not required to be directly bonded to the equipotential grid.
(5) Metal Wiring Methods and Equipment. Metal-sheathed cables and raceways, metal piping, and all fixed metal parts, as well as metallic surfaces of electrical equipment, must be bonded to the equipotential grid if located:
(1) Within 5 ft horizontally of the inside walls of the permanently installed pool, and outdoor spa or hot tub, and
(2) Within 12 ft measured vertically above the maximum water level of the permanently installed pool, outdoor spa, and outdoor hot tub, or any observation stands, towers, or platforms or any diving structures.
An equipotential grid is now required in or under the permanently installed pool, outdoor spa, and outdoor hot tub deck to help mask stray voltage from utility wiring errors, deteriorating primary utility neutral conductors, ground faults that haven't cleared, as well as appliance and equipment leakage current.
(C) Equipotential Grid. A solid copper conductor not smaller than 8 AWG must be used to bond the metallic parts of a permanently installed pool, outdoor spa, and outdoor hot tub as specified in 680.26(B) to an equipotential grid. The termination of the bonding conductor must be made by exothermic welding, listed pressure connectors, or listed clamps that are suitable for the purpose. (Fig. 21)
To properly mask stray voltage, an equipotential grid must extend under the permanently installed pool, outdoor spa, and outdoor hot tub, and walking surfaces for 3 ft horizontally from the water. The equipotential grid must be formed from one or more of the following: (Fig. 22 below)
(1) Structural Reinforcing Steel. Structural reinforcing steel of the concrete permanently installed pool, outdoor spa, and outdoor hot tub.
(2) Bolted or Welded Metal Pools. The walls of a bolted or welded metal permanently installed pool, outdoor spa, and outdoor hot tub.
(3) Other Methods. The equipotential grid can be constructed as specified in (a) through (c).
(a) Materials and Connections. The equipotential grid can be constructed with 8 AWG bare solid copper conductors that are bonded to each other at all points of crossing.
(b) Grid. The equipotential grid must cover the contour of the permanently installed pool, outdoor spa, and outdoor hot tub, and deck extending 3 ft horizontally from the water. The equipotential grid must be arranged in a 1 ft × 1 ft network of conductors in a uniformly spaced perpendicular grid pattern with a tolerance of 4 in.
(c) Securing. The equipotential grid must be secured.
#21. 695.4 CONTINUITY OF POWER
A new sentence clarifies that the “carry the locked rotor current indefinitely” requirement only applies to sizing the fire pump circuit protective devices, not the circuit conductors to the fire pump motor.
(B) Supervised Connection.
(1) Overcurrent Device Selection. The overcurrent protective device(s) must be selected or set to carry indefinitely the sum of the locked-rotor current of the fire pump motor(s) and the pressure maintenance pump motor(s) and the full-load current of the associated fire pump accessory equipment when connected to this power supply. The requirement to carry the locked-rotor currents indefinitely does not apply to fire pump motor conductors.
#22. 695.6 POWER WIRING
The text was revised to alert Code users that the branch-circuit conductors for a fire pump motor are sized in accordance with 430.22. In addition, branch-circuit conductors must be sized to accommodate the voltage drop requirements of 695.7.
(C) Conductor Size.
(1) Fire Pump Motors and Other Equipment. Conductors supplying fire pump motors and accessory equipment must be sized no less than 125 percent of the sum of the motor full-load currents as listed in Table 430.248 or 430.250, plus 100 percent of the ampere rating of the fire pumps accessory equipment.
(2) Fire Pump Motors Only. Conductors supplying a single fire pump motor must be sized in accordance with the requirements of 430.22.
Author's Comment: This means that the branch-circuit conductors to a single fire pump motor must have an ampere rating of not less than 125% of the fire pump motor full-load current (FLC) as listed in Table 430.248 or 430.250.
Question: What size conductor is required for a 25-hp, 208V 3-phase fire pump motor? (Fig. 23)
(a) 4 AWG (b) 3 AWG (c) 2 AWG (d) 1 AWG Conductors sized at 125% of the motor's FLC in Table 430.250
FLC of 25 hp = 74.8A, Table 430.250
Conductor = 74.8A × 1.25
Conductor = 93.5A
Answer: 3 AWG at 75°C is rated 100A
Note: Fire pump motor circuit protective device size must be set to carry indefinitely the sum of the locked-rotor current of the fire pump motor. According to Table 430.151(B), the locked-rotor current of a 25-hp, 208V 3-phase motor is 404A.
In addition, branch circuit conductors for a fire pump motor must be sized to accommodate the voltage drop requirements of 695.7.
#23. 700.27 COORDINATION
The overcurrent protective device of an emergency power system must now be selectively coordinated. This means circuit protection schemes confine the interruption to a particular area. For example with selective coordination, if a short circuit or ground fault occurs in a branch circuit, the only protection device that will open will be the one protecting just that branch circuit. Without selective overcurrent protection coordination, the feeder circuit protection device might open, leaving the entire system without power.
Overcurrent protection devices for emergency power systems must be selectively coordinated with all supply side overcurrent protective devices.
#24. 760.21 GFCI AND AFCI PROTECTION
This new rule prohibits AFCI protection of the 120V circuit that supplies power for a nonpower-limited fire alarm system.
The power source for a nonpower-limited fire alarm circuit cannot be supplied through groundfault circuit interrupters or arc-fault circuit interrupters. (Fig. 24 at right)
Author's Comment: This GFCI/AFCI limitation only applies to the circuit that supplies a nonpower-limited fire alarm system. Smoke detectors connected to a 15A or 20A, 120V circuit must be AFCI-protected if located in the bedroom of a dwelling unit [210.12(B)] because according to NFPA 72, National Fire Alarm Code, the circuit for the smoke detectors isn't the power source of a nonpower-limited fire alarm circuit.
#25. 800.24 MECHANICAL EXECUTION OF WORK
A new FPN alerts the Code user to a comprehensive standard that identifies what “installed in a neat and workmanlike manner” means.
Equipment and cabling must be installed in a neat and workmanlike manner.
FPN: Information describing industry practices can be found in ANSI/NECA/BICSI 568, Standard for Installing Commercial Building Telecommunications Cabling.