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Stumped by the Code?

May 23, 2011 4:20 PM, By Mike Holt, NEC Consultant

Your most pressing National Electrical Code (NEC) questions answered

All questions and answers are based on the 2011 NEC.

Q. Can receptacles installed above the kitchen counter also be used to meet the 6-ft requirements of 210.52(A)(1)?

A. Not according to newly added Sec. 210.4(A)(4). Counter receptacles required by 210.52(C) can’t be considered for the receptacles required by 210.52(A), as shown in the Figure.

Q. What are the requirements for the installation of arc fault circuit interrupters (AFCIs) for new construction?

A. The combination AFCI is a circuit breaker that protects downstream branch circuit wiring as well as cord sets and power supply cords; an outlet branch circuit AFCI (receptacle) is installed as the first outlet in a branch circuit to protect downstream branch circuit wiring, cord sets, and power supply cords.

All 15A or 20A, 120V branch circuits in dwelling units supplying outlets in family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, or similar rooms/ areas must be protected by a listed AFCI device of the combination type [210.12(A)].

Exception 1: AFCI protection can be of the branch circuit type located at the first outlet if the circuit conductors are installed in RMC, IMC, EMT, or Type MC or steel-armored Type AC cable meeting the requirements of 250.118, and the AFCI device is contained in a metal outlet or junction box.

Exception 2: Where a listed metal or nonmetallic conduit or tubing is encased in not less than 2 in. of concrete for the portion of the branch circuit between the branch circuit overcurrent device and the first outlet, an outlet branch circuit AFCI at the first outlet is permitted to provide protection for the remaining portion of the branch circuit.

Exception 3: AFCI protection can be omitted for an individual branch circuit to a fire alarm system in accordance with 760.41(B) and 760.121(B), if the circuit conductors are installed in RMC, IMC, EMT, or steel sheath Type AC or MC cable that qualifies as an equipment grounding conductor in accordance with 250.118, with metal outlet and junction boxes.

Q. What are the requirements for bonding of service raceways?

A. According to 250.92(A), the metal parts of service equipment indicated below must be bonded together in accordance with 250.92(B).

1. Metal raceways containing, enclosing, or supporting service conductors.
2. Metal enclosures containing service conductors. Metal raceways or metal enclosures containing feeder and branch circuit conductors are required to be connected to the circuit equipment grounding conductor in accordance with 250.86.

As per 250.92(B), bonding jumpers shall be used around reducing washers, or oversized, concentric, or eccentric knockouts are required. Standard locknuts are permitted to make a mechanical connection of the raceway(s), but they can’t serve as the bonding means required by this section.

Electrical continuity at service equipment, service raceways, and service conductor enclosures must be ensured by one of the following methods:

1. Neutral conductor. By bonding the metal parts to the service neutral conductor.
2. Threaded fittings. By terminating metal raceways to metal enclosures by threaded hubs on enclosures if made up wrenchtight.
3. Threadless fittings. By terminating metal raceways to metal enclosures by threadless fittings if made up tight.
4. Other listed devices, such as bonding-type locknuts, bushings, wedges, or bushings with bonding jumpers.

Q. Does the Code allow the use of ceiling-support wires to support raceways and cables?

A. No. Raceways, cable assemblies, boxes, cabinets, and fittings must be securely fastened in place. The ceiling-support wires or ceiling grid must not be used to support raceways and cables (power, signaling, or communications). However, independent support wires that are secured at both ends and provide secure support are permitted [300.11(A)].

1. Fire-rated ceiling assembly. Electrical wiring within the cavity of a fire-rated floor-ceiling or roof-ceiling assembly can be supported by independent support wires attached to the ceiling assembly. The independent support wires must be distinguishable from the suspended-ceiling support wires by color, tagging, or other effective means.
2. Nonfire-rated ceiling assembly. Wiring in a nonfire-rated floor-ceiling or roof-ceiling assembly can be supported by independent support wires attached to the ceiling assembly. The independent support wires must be distinguishable from the suspended-ceiling support wires by color, tagging, or other effective means.

Q. What does the NEC require when replacing receptacles in locations that now require tamper-resistant receptacles?

A. Listed tamper-resistant receptacles must be provided where replacements are made at receptacle outlets that are required to be tamper resistant elsewhere in this Code [406.4(D)(5)].

Q. What does the NEC require when replacing receptacles in locations that now require weather-resistant receptacles?

A. Weather-resistant receptacles must be provided where replacements are made at receptacle outlets that are required to be so protected elsewhere in the Code [406.4(D)(6)].

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