Stumped by the Code?
Q. My inspector approved the electrical rough-in stage of my project, but failed the final inspection because I installed a panel in an 8-foot × 5-foot walk-in closet. How can I convince the inspector to approve the installation?
A. I'm sorry you didn't know that 240.24(D) prohibits overcurrent devices in the vicinity of easily ignitible material, such as in clothes closets. The panel needs to be moved to another location that's acceptable to the inspector (Fig. 1).
Q. Must the smoke detector circuit in a dwelling unit bedroom be AFCI-protected?
A. Sec. 210.12(B) requires all branch circuits that supply 15A and 20A, 125V outlets in dwelling unit bedrooms to be AFCI-protected. This would include the smoke detector circuit. However, the proposed change to 760.21 for the 2005 NEC would prohibit the use of GFCIs or AFCIs to protect a nonpower-limited fire alarm circuit (Fig. 2).
Q. Is AFCI protection required for bedroom circuits of a hotel guest room with space for sleeping, permanent provisions for cooking (2-burner cooktop), but no true areas for eating.
A. If the guest room has space for sleeping as well as permanent provisions for cooking and sanitation, then it's a dwelling unit as defined by Art. 100. Since the guest room is a dwelling unit as defined in Art. 100, all branch circuits that supply 15A and 20A bedroom outlets must be AFCI-protected [210.12(B)].
Note: An outlet is defined as a point in the wiring system at which current is taken to supply utilization equipment.
Q. Are AFCI receptacles available?
A. AFCI receptacles aren't currently available in the marketplace because they don't meet the AFCI protection requirements as outlined in 210.12.
Q. Can I connect the ground rods for the lightning protection system to the grounding system of the building?
A. As noted in 250.106, the NEC requires the lightning protection system to be bonded to the building or structure grounding electrode system. However, the NEC doesn't specify what size bonding conductor you should use to bond the lightning protection electrode to the building electrode.
Note: Sec. 250.53(C), which doesn't apply to the bonding of the lightning protection electrode to the building electrode, requires the bonding jumper used to connect grounding electrodes together to form the grounding electrode system (250.50) to be installed in accordance with 250.64(A), (B), and (E), sized in accordance with 250.66, and connected in the manner specified in 250.70.
According to 250.66(A), a 6 AWG copper conductor is the largest conductor required as the sole connection to a ground rod to bond.
Q. We have a difference of opinion with local inspectors when it comes to supporting lay-in light fixtures in a drop ceiling. What does the Code have to say about this?
A. The Code requires lay-in luminaires to be securely fastened to the ceiling-framing member by mechanical means like bolts, screws, or rivets. Listed clips identified for use with the type of ceiling framing member and luminaire can also be used for this purpose [410.16(C)]. But review the plans and check with the building official for special requirements per building code if the ceiling is a fire-resistive assembly.
Q. Can the feeder conductor sizes listed in Table 310.15(B)(6) instead of those in Table 310.16 be used to supply individual dwelling units of a multifamily dwelling-unit building? What if the voltage to each dwelling unit is 120/208V single-phase?
A. Table 310.15(B)(6) can be used to size feeder conductors for individual dwelling unit feeders, but only if the system voltage is 120/240V single-phase.
Clashing with your local inspector? Taking issue with the AHJ's latest ruling? Send your questions to firstname.lastname@example.org.