NEC Q and A: Questions and Answers on the National Electrical Code
Beginners will find answers to practical on-the-job problems, and experts will be able to explore in depth the reasons behind NEC rules and the additional issues related to each question in this examination of frequently- and not-so-frequently-asked questions. Based on questions posed to, and answered by, NFPA's Advisory Services engineers. Includes coverage of: Where GFCI, AFCI, and overcurrent protection are required. “Parallel paths” and “objectionable current over grounding connectors.” Ampacity calculations coordinated with termination and continuous load requirements. How to use dual-marked wiring cables. Use of cable trays permitted in other than industrial occupancies. Low-voltage lighting systems. Overcurrent protection requirements for motors. Classification of hazardous locations. Definition of Class 1, 2, and 3 remote-control, signaling, and power-limited circuits. NEC® Q&A: Questions and Answers on the National Electrical Code® includes coverage of: Where GFCI, AFCI, and overcurrent protection are required "Parallel paths" and "objectionable current over grounding connectors". Ampacity calculations coordinated with termination and continuous load requirements. How to use dual-marked wiring cables. Use of cable trays permitted in other than industrial occupancies. Low-voltage lighting systems. Overcurrent protection requirements for motors. Classification of hazardous locations. Definition of Class 1, 2, and 3 remote-control, signaling, and power-limited circuits.
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4 Are electrical substations covered by the NEC?
7 Are all switches required to have a shortcircuit or interrupting rating?
10 How are the requirements for working spaces determined?
11 What working spaces apply to HVAC equipment?
14 What clearance is required for equipment that is serviced only while
What types of devices are permitted for providing AFCI protection?
Do unit load values for general lighting include factors for continuous
15 What are the differences in requirements for boxes in combustible
19 Do the extended support lengths for RMC apply where threepiece cou
cords and extension cords?
4 Is there any length limitation on flexible conduit runs or flexible fittings
7 What type of portable lighting is permitted in garages and aircraft
11 What loads are permitted on the equipment branch of an essential electri
Are goosenecks permitted to be located below service drop
Where is an overcurrent device required to be located in a circuit?
Must water piping and steel be bonded where there is no building?
17 Is a lighting pole considered grounded by a direct connection to
20 Should a service lateral include a grounding or bonding conductor?
Wiring Methods and Materials
6 Are receptacles permitted in plenum ceilings?
8 When are solid conductors allowed in raceways?
13 How are ampacity calculations coordinated with termination and continu
Special Equipment Conditions and Systems
4 How is bonding to be accomplished for hydromassage bathtubs?
7 Which conductors for fire pumps require special routing
10 Is more than one emergency system permitted in a building?
13 How do I know if a circuit is Class l Class 2 or Class 3?
15 How are rules for data and communications circuits applied to a Class 2
17 Are separations required between power and instrument or control
21 What raceways or equipment are required to be grounded in communica
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AFCI ampacity amperes appliance apply Article l00 authority having jurisdiction AWG conductor Based on NEC bonding jumper branch circuit building cable trays ceiling circuit breaker Class l circuits clearances combustible connected continuous load countertop disconnecting means ductors dwelling units electrical equipment emergency enclosure energized equipment grounding conductor example fault current feeder fire alarm fire pump flexible cords GFCI protection grounding electrode conductor hazardous HVAC installed insulation Keywords listed luminaires MC cable metal conduit minimum motor National Electrical Code NEC Handbook NEC References neutral NFPA 70E NM cable noncombustible nonmetallic overcurrent device overcurrent protection overload panel panelboard patient care areas permitted raceway receptacle outlet Related Questions secondary conductors service conductors service disconnecting service drop service equipment service-entrance conductors shown in Figure sizes space specific switch Table tap conductors temperature tion transformer Type NM ungrounded utility voltage volts wall wet location wiring methods