eep April 7, 2025 NEC 300-399 NEC Quizzes Report a question What’s wrong with this question? You cannot submit an empty report. Please add some details. 0% Article 300-399 Part02 This comprehensive quiz contains 50 questions carefully selected from the National Electrical Code (NEC) Articles spanning 300 through 399. This section of the NEC addresses crucial aspects of wiring methods, materials, and general requirements for electrical installations within this portion of the code. The questions in this quiz are chosen randomly to provide a thorough assessment of your knowledge across these essential NEC articles. While we strive for a diverse set of questions, some fundamental principles may be revisited in different contexts due to their relevance to multiple sections within this range. This approach ensures a robust evaluation of your understanding. We encourage you to actively participate and provide feedback. If you identify any issues or have suggestions for improving the quiz questions, please report them. Your contributions are invaluable in helping us maintain the accuracy and effectiveness of these learning resources. The NEC allows splices and taps but specifies accessibility and space limits. 1 / 50 What is required for splices and taps made within a wireway (376.56(A))? a. Splices and taps must fill no more than 50% of the wireway’s area. b. Only factory-made splices and taps are allowed. c. Splices and taps must be located at the ends of the wireway. d. Splices and taps are permitted if accessible and do not fill more than 75% of the wireway’s area. Incorrect. Splices and taps must be accessible and not exceed 75% of the wireway’s area. Correct! Accessibility and space limits apply to splices and taps. Splices and taps are permitted in wireways as long as they are accessible and do not fill more than 75% of the wireway’s interior cross-sectional area. Conductor space limits ensure adequate heat dissipation and mechanical integrity. 2 / 50 What is the maximum number of conductors allowed in a cellular metal floor raceway (374.22)? a. The combined cross-sectional area of conductors cannot exceed 40% of the raceway's interior. b. No restriction applies. c. Limited to three conductors per cell. d. Up to 50% of the raceway's interior cross-sectional area. Incorrect. The limit is 40% of the raceway’s interior cross-sectional area. Correct! The combined cross-sectional area of conductors must not exceed 40%. The NEC limits the combined cross-sectional area of conductors in cellular metal floor raceways to 40% of the interior cross-sectional area to maintain system integrity and prevent overheating. Marking requirements ensure proper identification and application of IBP systems. 3 / 50 What information must be included in the marking on IBP systems (369.120)? a. Only the voltage and ampacity ratings. b. The manufacturer’s logo and serial number. c. Only the rated peak withstand current. d. Maximum voltage, ampacity, equivalent AWG size, and conductor temperature. Incorrect. NEC requires a range of detailed markings for IBP systems. Correct! Markings must include key specifications for safe and compliant use. Markings on IBP systems must include details such as maximum voltage, ampacity, equivalent AWG size, conductor temperature, and other essential ratings to comply with NEC requirements. Internal joiners reduce the allowable conductor fill compared to external joiners. 4 / 50 What is the maximum cross-sectional area for conductors in strut-type channel raceways using internal joiners (384.22)? a. No restriction applies. b. 50% of the raceway's interior area. c. 40% of the raceway's interior area. d. 25% of the raceway's interior area. Incorrect. Internal joiners limit conductor fill to 25% of the raceway’s crosssectional area. Correct! Internal joiners allow a maximum fill of 25%. For strut-type channel raceways with internal joiners, the conductors cannot exceed 25% of the interior cross-sectional area to ensure adequate space for heat dissipation and conductor safety. Thermal expansion fittings are essential for long, straight runs. 5 / 50 What must be provided to accommodate thermal expansion in nonmetallic wireways (378.44)? a. Expansion fittings for changes of 0.25 inches or greater. b. Flexible connectors. c. No provisions are required for thermal expansion. d. Expansion joints every 10 feet. Incorrect. Expansion fittings are mandatory for significant thermal length changes. Correct! Expansion fittings must be used for changes of 0.25 inches or greater. Expansion fittings are required for nonmetallic wireways when thermal expansion or contraction is expected to result in a length change of 0.25 inches or greater, ensuring structural integrity. The NEC specifies environments unsuitable for multioutlet assemblies. 6 / 50 Where is the use of a multioutlet assembly prohibited (380.12)? a. In hazardous locations, hoistways, or where subject to severe physical damage. b. For surface mounting on walls. c. In dry locations. d. In residential applications. Incorrect. Multioutlet assemblies are restricted in hazardous or high-risk environments. Correct! Hazardous locations, hoistways, and physically risky areas are prohibited for multioutlet assemblies. Multioutlet assemblies cannot be used in hazardous locations, hoistways, areas subject to corrosive vapors or severe physical damage, or where voltage exceeds 300 volts unless specific conditions are met. Protection of bends prevents damage to the conductors and assembly. 7 / 50 What must be done to protect bends in nonmetallic extensions (382.24(A))? a. No protection is necessary. b. Tape over the bends for insulation. c. Cover the bends with a cap to prevent physical damage. d. Leave the bends exposed. Incorrect. Bends must be covered with caps for protection. Correct! Caps are required to protect bends from damage. Bends in nonmetallic extensions must be covered with a cap to protect the assembly from physical damage, ensuring durability and compliance with NEC standards. NEC requires specific measures to secure busway ends. 8 / 50 How must dead ends of busways be treated (368.58)? a. Sealed with electrical tape. b. Closed using an approved cover or cap. c. Left open for future connections. d. Covered with insulating material. Incorrect. Approved covers or caps must be used to close busway dead ends. Correct! Dead ends must be secured with an approved cover or cap. Dead ends of busways must be closed using an approved cover or cap to prevent exposure to live parts and ensure safety. Proper securing prevents sagging and ensures alignment. 9 / 50 How must a strut-type channel raceway be secured in a surface mount installation (384.30(A))? a. Only at terminations. b. At intervals not exceeding 10 feet and within 3 feet of terminations. c. At intervals of 6 feet and at every joint. d. No specific securing is required. Incorrect. The raceway must be secured at specified intervals for surface mounting. Correct! Strut-type channel raceways require securing at 10-foot intervals and near terminations. Surface-mounted strut-type channel raceways must be secured with external retention straps at intervals not exceeding 10 feet and within 3 feet of terminations to maintain stability. Ampacity is determined by conductor size and NEC guidelines. 10 / 50 What is the maximum allowed ampacity for nonmetallic extensions using 14 AWG conductors (382.104)? a. 25 amperes. b. 10 amperes. c. 20 amperes. d. 15 amperes. Incorrect. The ampacity for 14 AWG conductors is limited to 20 amperes. Correct! 20 amperes is the maximum ampacity for 14 AWG conductors in nonmetallic extensions. The ampacity of 14 AWG conductors used in nonmetallic extensions is limited to 20 amperes as per NEC requirements. Proper closure prevents exposure to conductors and ensures system safety. 11 / 50 How must dead ends of nonmetallic wireways be treated (378.58)? a. Closed with adhesive tape. b. Closed using listed fittings. c. No specific treatment is required. d. Left open for ventilation. Incorrect. Dead ends must be closed using listed fittings. Correct! Dead ends must be closed with listed fittings. Dead ends of nonmetallic wireways must be closed using listed fittings to maintain system safety and compliance with NEC requirements. Cablebus systems are designed for larger current-carrying capacities. 12 / 50 What is the minimum conductor size allowed for use in a cablebus system (370.20(A)(2))? a. 4 AWG. b. 8 AWG. c. 2 AWG. d. 1/0 AWG. Incorrect. The smallest conductor size for cablebus systems is 1/0 AWG. Correct! 1/0 AWG is the minimum allowable size for conductors in a cablebus system. Conductors in a cablebus system must be at least 1/0 AWG to comply with NEC requirements for adequate current-carrying capacity. The framework may serve as an equipment grounding conductor if it complies with NEC standards. 13 / 50 What is required for grounding the cablebus framework (370.60)? a. Grounding is not required for the framework. b. Only the conductors inside the framework need grounding. c. The framework can be used as the equipment grounding conductor if it meets NEC requirements. d. Only a separate grounding conductor must be installed. Incorrect. The framework can be used as the grounding conductor if properly evaluated. Correct! The framework can serve as the equipment grounding conductor when compliant. The cablebus framework can serve as the equipment grounding conductor if it meets the requirements of NEC 250.118(A)(12) and is tested for ground-fault current-carrying performance. Flexible bus systems are versatile but require proper identification for certain environments. 14 / 50 Where are flexible bus systems permitted to be used (371.10)? a. Only indoors. b. Indoors, outdoors where listed, in corrosive or damp locations, and behind access panels. c. Only in dry locations. d. In air-handling spaces. Incorrect. Flexible bus systems are allowed in a range of environments if identified for the specific use. Correct! Flexible bus systems are versatile and suitable for various environments when properly listed. Flexible bus systems are permitted in various environments, including indoors, outdoors (if identified for such use), corrosive or damp locations, and behind access panels that are not used for air-handling purposes. Larger conductors are allowed only with special permission. 15 / 50 What is the maximum conductor size allowed in cellular concrete floor raceways (372.20)? a. 2 AWG. b. 1/0 AWG. c. No size limit applies. d. 2/0 AWG. Incorrect. The maximum conductor size is 1/0 AWG unless otherwise permitted. Correct! The maximum conductor size is 1/0 AWG. The NEC limits the conductor size in cellular concrete floor raceways to 1/0 AWG unless special permission is granted, ensuring safe and practical installations. Specific arrangements are required to maintain accessibility and safety. 16 / 50 How may a metal multioutlet assembly extend through dry partitions (380.76)? a. By routing within the partition with outlets placed as needed. b. Only if it is completely concealed within the partition. c. Only if the assembly is nonmetallic. d. By extending through the partition with removable caps or covers on exposed portions. Incorrect. The assembly must extend through the partition with accessible removable caps or covers. Correct! Removable caps or covers must be arranged for any exposed portions. A metal multioutlet assembly can extend through dry partitions if arrangements are made for removing caps or covers on all exposed portions, and no outlets are located within the partitions. Certain environments are unsuitable for nonmetallic extensions. 17 / 50 Where is the use of nonmetallic extensions prohibited (382.12)? a. In unfinished basements, attics, or roof spaces. b. In finished basements. c. In office spaces. d. On residential walls. Incorrect. Nonmetallic extensions cannot be used in unfinished spaces like basements and attics. Correct! These areas are not allowed for nonmetallic extension installations. Nonmetallic extensions are not permitted in unfinished basements, attics, or roof spaces due to safety concerns, including exposure to physical damage or environmental hazards. NEC emphasizes using specified components for safety and compliance. 18 / 50 What is required for all connections or terminations in IBP systems (369.20)? a. Any compatible connectors can be used. b. Terminations require adhesive-sealed connectors. c. Manufacturer-supplied terminating means must be used. d. Connections must use standard wire nuts. Incorrect. Only manufacturer-supplied terminating means are acceptable for IBP systems. Correct! Manufacturer-supplied terminating means are mandatory for IBP connections. All connections and terminations in IBP systems must use manufacturer-supplied terminating means to ensure safety and compatibility, as required by the NEC. Proper marking ensures compliance and safety during use. 19 / 50 What marking is required on concealable nonmetallic extensions (382.120)? a. Voltage rating and conductor size. b. Only the manufacturer’s name. c. No marking is required. d. Material of conductors, maximum temperature rating, and ampacity. Incorrect. The marking must include material, temperature rating, and ampacity. Correct! These markings ensure safe and compliant use of nonmetallic extensions. Concealable nonmetallic extensions must be marked with the material of conductors, maximum temperature rating, and ampacity to ensure compliance with NEC requirements and proper application. Regular support intervals maintain stability and alignment. 20 / 50 How must metal wireways be supported for horizontal runs (376.30(A))? a. Only at endpoints. b. Every 3 feet. c. At each end and at intervals not exceeding 5 feet. d. No support is required. Incorrect. Support is required every 5 feet unless otherwise specified. Correct! Horizontal runs must be supported at 5-foot intervals. Metal wireways must be supported at each end and at intervals not exceeding 5 feet for horizontal runs, unless otherwise listed for longer spans. The wireway’s use as a grounding conductor depends on its listing. 21 / 50 Can a metal wireway serve as an equipment grounding conductor (376.60)? a. No, a separate grounding conductor is always required. b. Yes, if listed for use as an equipment grounding conductor. c. Only when the wireway is made of aluminum. d. Grounding is not required for wireways. Incorrect. The wireway must be listed to serve as a grounding conductor. Correct! A listed wireway can act as an equipment grounding conductor. A listed metal wireway can serve as an equipment grounding conductor in compliance with NEC 250.118(A)(13). Certain environments pose safety risks or are not conducive to flexible bus systems. 22 / 50 Where is the use of flexible bus systems prohibited (371.12)? a. In hoistways, hazardous locations (unless permitted), and air-handling spaces. b. In corrosive environments. c. In wet locations. d. For feeder circuits. Incorrect. These locations are explicitly restricted for flexible bus systems. Correct! Flexible bus systems are prohibited in these environments. Flexible bus systems cannot be used in hoistways, hazardous locations (unless specifically permitted by NEC Chapter 5), or air-handling spaces. Support intervals for horizontal runs are specific to maintain stability. 23 / 50 How must nonmetallic wireways be supported when installed horizontally (378.30(A))? a. Only at endpoints. b. Every 3 feet and at each joint. c. At intervals not exceeding 10 feet. d. Every 5 feet and at each joint. Incorrect. Support for horizontal runs is required every 3 feet and at joints. Correct! Nonmetallic wireways require horizontal support every 3 feet and at joints. Nonmetallic wireways must be supported horizontally at intervals not exceeding 3 feet and at each joint to ensure proper alignment and system stability. Support intervals ensure proper alignment and prevent sagging. 24 / 50 How often must busways be supported (368.30)? a. Only at endpoints. b. Every 3 feet. c. Every 5 feet unless otherwise designed and marked. d. Every 7 feet. Incorrect. Support is required every 5 feet unless marked otherwise. Correct! Support intervals must not exceed 5 feet. Busways must be securely supported at intervals not exceeding 5 feet unless specifically designed and marked for greater intervals. Conductor support ensures stability and prevents sagging. 25 / 50 How often must the insulated conductors in a horizontal run of a cablebus be supported (370.30(B))? a. Every 5 feet. b. Every 10 feet. c. Every 3 feet. d. Only at termination points. Incorrect. Conductors in horizontal runs must be supported every 3 feet. Correct! Conductors must be supported at intervals of 3 feet in horizontal runs. In horizontal runs, conductors within a cablebus must be supported at intervals not exceeding 3 feet to maintain alignment and mechanical integrity. NEC specifies detailed labeling for safety and compliance. 26 / 50 What information must be included on the nameplate of a cablebus system (370.120(A))? a. Manufacturer’s name, voltage rating, maximum conductor diameter, number of conductors, and ampacity. b. No marking is required for cablebus systems. c. Conductor length and manufacturer’s name. d. Voltage rating and the manufacturer’s contact information. Incorrect. The nameplate must include all required details for compliance. Correct! Nameplates must contain all the specified information as per NEC standards. The nameplate on a cablebus system must include the manufacturer’s name or trade designation, voltage rating, maximum conductor diameter, number of conductors, and ampacity to ensure proper identification and application. Splicing and tapping locations are explicitly defined for safety. 27 / 50 How must splices and taps be made in cellular metal floor raceways (374.56)? a. In any section of the raceway. b. By twisting wires together and insulating them. c. Using loop wiring anywhere in the system. d. Only in header access units or junction boxes. Incorrect. Splices and taps are restricted to header access units or junction boxes. Correct! Splices and taps must only occur in header access units or junction boxes. Splices and taps must only be made in header access units or junction boxes to ensure safe and compliant connections, avoiding unintended conductor exposure. Exceptions exist for short lengths of reduced-ampacity busways. 28 / 50 What is required for overcurrent protection when a busway is reduced in ampacity (368.17(B))? a. No protection is needed if the reduction is less than 25%. b. Overcurrent protection must always be installed at the reduction point. c. Protection is required unless the smaller busway is 50 feet or shorter and meets other criteria. d. The smaller busway must always have separate protection. Incorrect. Exceptions are specified for short, reduced-ampacity busways in industrial settings. Correct! Exceptions apply for short busways with reduced ampacity Overcurrent protection is not required for smaller busways in industrial settings if they are less than 50 feet long and have an ampacity at least one-third the rating of the upstream device. NEC specifies comprehensive labeling for busways. 29 / 50 What marking is required on a busway nameplate (368.320)? a. Voltage, current rating, frequency, and other key operational data. b. Manufacturer’s logo only. c. Voltage rating and conductor material. d. No specific marking is required. Incorrect. The nameplate must include detailed operational data as specified by the NEC. Correct! Nameplates require comprehensive labeling for identification and safety. A busway nameplate must display information including voltage, current rating, frequency, and manufacturer’s name or trademark to ensure proper identification and application IBP systems are not suitable for certain environments unless explicitly allowed. 30 / 50 Where is the use of IBP systems prohibited (369.12)? a. For voltages exceeding 15,000 volts. b. In hazardous locations unless permitted by other articles. c. For installations exceeding 10 feet in length. d. In wet locations. Incorrect. IBP systems are prohibited in hazardous locations unless explicitly allowed. Correct! IBP systems are restricted in hazardous locations without NEC permission. IBP systems cannot be used in hazardous locations unless specifically permitted by other articles of the NEC, ensuring safety in such environments. Durability limitations restrict the use of nonmetallic wireways in certain environments. 31 / 50 Where is the use of nonmetallic wireways prohibited (378.12)? a. For low-voltage installations. b. In outdoor installations. c. In areas subject to physical damage or hazardous locations unless otherwise permitted. d. In damp or wet locations. Incorrect. Nonmetallic wireways are restricted in areas subject to physical damage or hazardous conditions. Correct! These restrictions ensure safe usage of nonmetallic wireways. Nonmetallic wireways cannot be used in areas subject to physical damage, hazardous locations, or environments for which they are not listed, ensuring compliance with safety standards. The material prevents liquids from entering the floor opening. 32 / 50 What material must be provided at floor openings for vertical riser busways in non-industrial establishments (368.10(C)(2)(b))? a. Non-conductive grommets. b. A 4-inch-high curb within 12 inches of the opening. c. No additional materials are required. d. Heat-resistant padding. Incorrect. A 4-inch-high curb is required for vertical riser busways. Correct! The curb prevents liquid entry into floor openings. A minimum 4-inch-high curb must be installed within 12 inches of floor openings for riser busways to prevent liquids from entering, ensuring safety and system integrity. Expansion fittings handle thermal expansion and vibration. 33 / 50 What is required for busway expansion fittings (368.244)? a. No expansion fittings are necessary for busways. b. Fittings are required for long, straight runs or crossings over building joints. c. Only flexible conduit can serve as an expansion fitting. d. Expansion fittings are only required for busways over 100 feet long. Incorrect. Expansion fittings are necessary for long runs and joint crossings. Correct! Expansion fittings accommodate thermal and mechanical movement. Expansion fittings are required in long, straight busway runs or when crossing building joints to allow for thermal expansion and contraction or vibration. The enclosure’s role as a grounding conductor depends on its listing. 34 / 50 What grounding requirements apply to busways (368.60)? a. No grounding is required for enclosed busways. b. Only a separate grounding conductor must be used. c. The busway enclosure may serve as a grounding conductor if listed for such use. d. The busway enclosure itself cannot be used as a grounding conductor. Incorrect. The enclosure may serve as a grounding conductor if appropriately listed. Correct! The enclosure can be used as a grounding conductor if listed for the purpose. The busway enclosure can serve as a grounding conductor if it is listed for such use. Otherwise, a separate equipment grounding conductor must be connected. Fire safety measures are critical at penetrations. 35 / 50 What must be provided when IBP systems pass through fire-rated barriers (369.110)? a. No special requirements are necessary. b. Use of fireproof tape. c. Installation of metallic seals. d. Fire barriers must be installed. Incorrect. Fire barriers must be installed where fire-rated structures are penetrated. Correct! Fire barriers are essential for fire safety in these situations. Fire barriers are required when IBP systems penetrate fire-rated walls, floors, or ceilings, ensuring the containment of fire and smoke as per NEC standards. Junction boxes must protect against water and maintain electrical continuity. 36 / 50 How must junction boxes in cellular concrete floor raceways be installed (372.18(C))? a. At least 2 inches above the floor surface. b. Installed below floor level with no sealing required. c. Flush with the floor and open to prevent water entry. d. Leveled to floor grade, sealed against water, and mechanically continuous with the header. Incorrect. Junction boxes must be sealed and leveled to prevent water ingress and ensure continuity. Correct! Junction boxes must be sealed, leveled, and continuous with the header. Junction boxes in cellular concrete floor raceways must be leveled to the floor grade, sealed to prevent water entry, and mechanically and electrically continuous with the header to meet NEC requirements. NEC prohibits splicing abandoned conductors within the raceway. 37 / 50 What action must be taken for abandoned outlets in cellular metal floor raceways (374.58)? a. Seal the outlet with a protective cap. b. Remove the circuit conductors supplying the abandoned outlet. c. Leave the conductors in place for future use. d. Splice and insulate the conductors within the raceway. Incorrect. The circuit conductors must be removed entirely Correct! Conductors supplying abandoned outlets must be removed from the raceway. Conductors supplying abandoned, discontinued, or removed outlets must be removed from the raceway. Splicing or re-insulating these conductors in the raceway is not allowed. Space limits ensure heat dissipation and proper conductor arrangement. 38 / 50 What is the maximum cross-sectional area of conductors allowed in a metal wireway (376.22(A))? a. No limit applies. b. 50% of the wireway's interior. c. 25% of the wireway's interior. d. 20% of the wireway's interior. Incorrect. The NEC specifies a maximum of 20% of the interior crosssectional area. Correct! Conductors can occupy up to 20% of the wireway’s interior area. The sum of the cross-sectional areas of all conductors in a wireway cannot exceed 20% of its interior cross-sectional area, ensuring proper spacing and heat dissipation. NEC specifies the maximum voltage for IBP applications. 39 / 50 What is the minimum rating for IBP systems in terms of voltage (369.10(5))? a. Only up to 10,000 volts. b. Up to 35,000 volts. c. No voltage limit applies. d. Up to 15,000 volts. Incorrect. IBP systems can be used for voltages up to 35,000 volts. Correct! The maximum voltage for IBP systems is 35,000 volts. IBP systems are permitted for use on power systems with voltages up to and including 35,000 volts, ensuring their suitability for high-voltage applications. The prohibition includes environments that may damage conductors or pose safety risks. 40 / 50 Where are conductors prohibited from being installed in precast cellular concrete floor raceways (372.12)? a. In dry commercial garages. b. In residential buildings. c. In locations with corrosive vapor or hazardous areas, except as permitted by the Code. d. In ceiling-mounted applications. Incorrect. Conductors are prohibited in environments with corrosive vapor or hazardous areas unless explicitly allowed. Correct! Conductors cannot be installed in corrosive or hazardous environments without specific permission. Conductors are not allowed in precast cellular concrete floor raceways where they may be exposed to corrosive vapors, hazardous locations (unless permitted by other NEC articles), or in commercial garages except for specific uses. NEC allows multiple wiring methods for branch circuits. 41 / 50 What wiring methods are permitted for branches from busways (368.56(A))? a. Various methods, including EMT, PVC, and MC cable. b. Only liquidtight conduit. c. Only flexible conduit. d. Only metallic conduit. Incorrect. Multiple wiring methods are permitted for busway branches Correct! EMT, PVC, MC cable, and others are approved for branch circuits. Branches from busways can use various approved methods, such as EMT, PVC, MC cable, and others listed in 368.56(A), ensuring flexibility in installations. NEC requires comprehensive information for system identification. 42 / 50 What must be included on the system nameplate for flexible bus systems (371.120(A))? a. Voltage rating and manufacturer’s contact information. b. Only the manufacturer’s logo. c. Voltage, phase, current rating, short-circuit current rating, and environmental ratings. d. Conductor length and insulation type. Incorrect. The nameplate must include detailed ratings and manufacturer information. Correct! Comprehensive markings are required for flexible bus systems. The system nameplate for flexible bus systems must include the voltage, phase, current rating, short-circuit current rating, environmental ratings, and the manufacturer’s name or trademark for proper identification and compliance. Pull box installations require adherence to specific dimensional standards. 43 / 50 What must be ensured when a multioutlet assembly is used as a pull box for insulated conductors of 4 AWG or larger (380.23(B))? a. Conductors must always be bent within 30 degrees. b. No specific requirements apply for larger conductors. c. The distance between raceway entries must comply with NEC 314.28 for straight and angle pulls. d. Conductors can be spliced anywhere within the assembly. Incorrect. The distances must comply with NEC 314.28 to ensure proper conductor handling. Correct! NEC 314.28 specifies the required distances for safe conductor pulls. When used as a pull box for 4 AWG or larger conductors, the distance between raceway entries must meet the minimum requirements of NEC 314.28 for straight and angle pulls, ensuring adequate space for safe conductor movement. Dead ends must be secured to prevent exposure or damage. 44 / 50 What action must be taken for dead ends of a wireway (376.58)? a. Marked for future use. b. Covered with electrical tape. c. Left open for future expansion. d. Closed using an approved cover or plate. Incorrect. Dead ends must be securely closed. Correct! Dead ends must be covered with an approved closure. Dead ends of a metal wireway must be securely closed with an approved cover or plate to maintain safety and system integrity. Proper support intervals are crucial for system stability. 45 / 50 How must flexible bus systems be supported (371.30)? a. Only at endpoints. b. No specific support intervals are required. c. At intervals not exceeding 3 feet for horizontal runs and 1 1/2 feet for vertical runs. d. At intervals not exceeding 5 feet. Incorrect. Support intervals are clearly defined to ensure stability. Correct! Flexible bus systems must follow these support intervals for proper installation. Flexible bus systems must be supported at intervals of 3 feet for horizontal runs and 1 1/2 feet for vertical runs, unless otherwise specified by the product listing. Fire safety measures are critical for penetrations. 46 / 50 What must be provided when a cablebus system passes through a firerated wall (370.18)? a. Flame-resistant tape. b. Fire barriers in accordance with NEC 300.21. c. Plastic conduits to insulate the conductors. d. No additional requirements. Incorrect. Fire barriers are required for fire-rated penetrations. Correct! Fire barriers are mandatory for fire-rated wall penetrations. When a cablebus system passes through fire-rated walls, it must be installed with fire barriers as specified in NEC 300.21 to ensure fire containment. Regular securing ensures stability and alignment. 47 / 50 . How often must nonmetallic extensions be secured when installed horizontally (382.30(A))? a. No securing is required. b. Every 18 inches. c. Every 12 inches. d. Every 8 inches. Incorrect. Nonmetallic extensions must be secured every 8 inches. Correct! Securement is required every 8 inches. Nonmetallic extensions must be secured at intervals not exceeding 8 inches for proper support and alignment during installation. Space limits are necessary for proper heat dissipation and safety. 48 / 50 What is the maximum allowable cross-sectional area of conductors within a nonmetallic wireway (378.22)? a. 30% of the wireway's interior cross-sectional area. b. No restriction applies. c. 25% of the wireway's interior cross-sectional area. d. 20% of the wireway's interior cross-sectional area. Incorrect. The limit for conductor fill is 20% of the wireway’s interior area. Correct! The conductor fill is limited to 20% of the wireway’s interior crosssectional area. Conductors in a nonmetallic wireway must not exceed 20% of the interior cross-sectional area, ensuring adequate spacing for heat dissipation and compliance with NEC standards. Clearance restrictions ensure safety in accessible areas. 49 / 50 Where are lighting busways prohibited from being installed (368.12(E))? a. In residential applications. b. In hazardous locations. c. In concealed spaces. d. Less than 8 feet above the floor or working platform unless covered. Incorrect. The required clearance is 8 feet unless a cover is installed. Correct! Clearance of 8 feet is required for safety. Lighting busways must not be installed less than 8 feet above the floor or working platform unless they are provided with an identified cover to prevent accidental contact. NEC specifies feeder protection requirements. 50 / 50 What overcurrent protection applies to flexible bus systems installed as feeders (371.17(B))? a. Overcurrent protection is required only at the load end. b. Overcurrent protection is not required for feeders. c. Only the upstream protection applies. d. Overcurrent protection must comply with NEC 215.3. Incorrect. NEC 215.3 specifies the overcurrent protection requirements for feeder systems. Correct! Feeder systems must follow the overcurrent protection requirements of NEC 215.3. Flexible bus systems installed as feeders must comply with NEC 215.3, which governs overcurrent protection for feeder circuits. Your score is LinkedIn Facebook Twitter 0% Restart quiz Exit Rate & Review Thank you for taking the time to leave us a review! Your feedback is greatly appreciated and helps us improve our services. Send feedback Leave a Reply Cancel replyYour email address will not be published. Required fields are marked * Comment* Name* Email* Website Save my name, email, and website in this browser for the next time I comment. Post Comment
