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 Part01 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. Grounding is necessary for all metal raceways to ensure safety. 1 / 50 How must grounding be provided for surface metal raceways (386.60)? a. Grounding is only required for raceways over 300 volts. b. The raceway enclosure must have a means for connecting an equipment grounding conductor. c. A separate grounding conductor must always be run alongside the raceway. d. Grounding is not required for metal raceways. Incorrect. Grounding is mandatory and must be provided through the raceway enclosure. Correct! The raceway must provide a means to connect an equipment grounding conductor. Surface metal raceway enclosures must have a means for connecting an equipment grounding conductor, such as a grounding terminal screw or lug, to comply with NEC requirements High-voltage conductors require visible warnings. 2 / 50 What marking is required for cable trays containing conductors over 600 volts (392.18(H))? a. No marking is necessary. b. Voltage rating only. c. A permanent warning notice reading “DANGER — HIGH VOLTAGE — KEEP AWAY.” d. Manufacturer's name and serial number. Incorrect. The specific warning message is mandatory. Correct! The warning ensures safety and compliance. Cable trays containing conductors over 600 volts must display a permanent, visible warning notice stating “DANGER — HIGH VOLTAGE — KEEP AWAY,” placed every 10 feet. Open wiring on insulators is versatile but has specific location requirements. 3 / 50 Where is open wiring on insulators permitted (398.10)? a. Indoors or outdoors in dry or wet locations, including areas with corrosive vapors. b. Only in concealed spaces. c. In temporary construction sites. d. Only in residential buildings. Incorrect. It is permitted indoors, outdoors, and in corrosive environments under specific conditions. Correct! This wiring method is allowed in these locations under proper conditions. Open wiring on insulators is allowed indoors or outdoors, in dry or wet locations, and in areas with corrosive vapors, provided appropriate insulation is used. NEC specifies approved methods for securing entries into cable trays. 4 / 50 How must raceways and cables entering a cable tray be secured (392.30(B))? a. Securing is not required. b. Using any available securing method. c. With cable ties only. d. With listed clamps, adapters, or raceway fittings. Incorrect. Listed clamps or adapters are required for secure entry. Correct! Listed securing methods ensure compliance. Raceways and cables entering a cable tray must be secured with listed clamps, adapters, or fittings to ensure stability and compliance. Space must remain for heat dissipation and proper conductor arrangement. 5 / 50 What is the maximum allowable fill for splices and taps in surface metal raceways with removable covers (386.56)? a. 50% of the raceway’s interior cross-sectional area. b. 75% of the raceway’s interior cross-sectional area. c. 100% of the raceway’s interior cross-sectional area. d. No limit applies. Incorrect. The maximum fill is 75% for splices and taps. Correct! Splices and taps can fill up to 75% of the raceway’s interior area. Splices and taps in surface metal raceways with removable covers are limited to filling no more than 75% of the raceway’s interior cross-sectional area to ensure safety and functionality. Accessibility and safety are key for electrical connections. 6 / 50 How must connections in busbar grid rails be made (393.57)? a. With push-on connectors without insulation. b. With listed insulating devices that are accessible after installation. c. Only in a concealed enclosure. d. Using solder only. Incorrect. Connections must be made using accessible and listed insulating devices. Correct! Listed insulating devices must be used, and the connections must be accessible. Connections in busbar grid rails must use listed insulating devices and remain accessible after installation to comply with NEC safety standards. Clearance ensures electrical safety and prevents contact 7 / 50 What clearance is required between open conductors and metal raceways or piping (398.19)? a. 50 mm (2 inches), or separated by a fixed nonconductor. b. 25 mm (1 inch). c. No clearance is required. d. 75 mm (3 inches). Incorrect. The required clearance is 50 mm (2 inches) or separation by a nonconductor. Correct! Conductors require 50 mm (2 inches) of clearance or fixed separation. Open conductors must maintain at least 50 mm (2 inches) of clearance from metal raceways, piping, or other conducting materials, or be separated by a fixed nonconductor. Nonmetallic materials cannot serve as grounding conductors. 8 / 50 What grounding requirement applies to surface nonmetallic raceways (388.60)? a. The raceway itself serves as the grounding conductor. b. A separate grounding conductor must always be installed when grounding is required. c. No grounding is required for nonmetallic raceways. d. A separate grounding conductor must only be used in outdoor installations. Incorrect. Nonmetallic raceways require a separate grounding conductor. Correct! A separate grounding conductor is mandatory in these installations. When equipment grounding is required, a separate grounding conductor must be installed within the surface nonmetallic raceway as the raceway material cannot serve as a grounding conductor. The disconnecting means must allow easy access for servicing and maintenance. 9 / 50 What is the requirement for the disconnecting means in a suspended ceiling power distribution system (393.21(A))? a. It must be accessible and within sight of the Class 2 power source. b. It can be located anywhere in the building. c. The disconnect must be installed within 20 feet of the system. d. No disconnecting means is required. Incorrect. The disconnecting means must be within sight of the Class 2 power source. Correct! The disconnecting means must be accessible and within sight of the Class 2 power source. The disconnecting means for the Class 2 power supply must be accessible and located within sight of the Class 2 power source to facilitate safe servicing and maintenance. NEC emphasizes grounding and bonding for discontinuities. 10 / 50 What must be done when cable trays are mechanically discontinuous (392.60(C))? a. Replace the cable tray system with conduit. b. Install a bonding jumper in accordance with NEC 250.102. c. No special action is required. d. Leave the segments disconnected. Incorrect. A bonding jumper is required to ensure continuity and safety. Correct! Bonding jumpers are essential for mechanically discontinuous cable trays. When cable trays are mechanically discontinuous, a bonding jumper sized per NEC 250.102 must connect the segments to maintain electrical continuity. The bushing material ensures the safety and longevity of the wiring. 11 / 50 What material is required for bushings used in open wiring through framing members (398.17)? a. Noncombustible, nonabsorbent insulating materials, supplemented by waterproof sleeves if the bushing is shorter than the hole. b. Noncombustible and nonabsorbent insulating materials. c. Any type of insulating material. d. Flexible plastic tubing. Incorrect. Both insulating bushings and waterproof sleeves are required under certain conditions. Correct! This ensures the conductors remain safe and out of contact with framing materials. Bushings for open wiring through framing members must be made of noncombustible, nonabsorbent insulating materials, with waterproof sleeves used when the bushing is shorter than the hole. Proper installation prevents damage and maintains system integrity. 12 / 50 How must junction boxes in underfloor raceway systems be installed (390.74)? a. Leveled to floor grade and sealed to prevent water or concrete ingress. b. Set at any convenient level. c. Covered with nonmetallic caps. d. Sealed with electrical tape. Incorrect. Junction boxes must be sealed and leveled to floor grade. Correct! Junction boxes must be properly sealed and leveled to floor grade. Junction boxes must be leveled to the floor grade and sealed to prevent the free entrance of water or concrete. For metal raceways, the boxes must be metal and electrically continuous with the raceways. Exposure to sunlight requires cables with specific markings. 13 / 50 What type of cables can be installed in a cable tray exposed to sunlight (392.10(A))? a. Only multiconductor cables. b. Cables that are identified as sunlight-resistant. c. Any cable type. d. Nonmetallic-sheathed cable only. Incorrect. Only sunlight-resistant cables can be installed in such conditions. Correct! Sunlight-resistant cables are required for exposed installations. Cables in cable trays exposed to sunlight must be identified as sunlight-resistant to prevent degradation. Corrosion protection ensures durability in harsh environments. 14 / 50 How must underfloor cable trays be constructed in corrosive environments (392.100(C))? a. Using standard steel materials. b. Corrosion-resistant or protected from corrosion. c. With a double layer of paint. d. No special construction is required. Incorrect. Special materials or coatings are required for corrosive environments. Correct! Corrosion resistance is mandatory for cable trays in such environments Cable trays in corrosive environments must be corrosion-resistant or protected as specified in NEC 300.6 to ensure longevity and safety. Some environments pose mechanical risks to this wiring method. 15 / 50 Where is the use of messenger-supported wiring prohibited (396.12)? a. In locations where sunlight exposure occurs. b. In hoistways or areas subject to physical damage. c. In industrial installations with qualified maintenance personnel. d. In residential buildings. Incorrect. The prohibition specifically applies to hoistways and damageprone areas. Correct! This wiring is not permitted in hoistways or areas subject to physical damage. Messenger-supported wiring cannot be installed in hoistways or locations where it is subject to physical damage, as these conditions compromise safety and system integrity. Proper spacing ensures optimal heat dissipation. 16 / 50 What spacing must be maintained between cables in a cable tray to qualify for maximum ampacity (392.80(A)(1)(c))? a. 1.5 times the cable diameter. b. At least one cable diameter. c. Two cable diameters. d. No spacing is required. Incorrect. The minimum required spacing is one cable diameter. Correct! A spacing of at least one cable diameter is required. To achieve maximum ampacity, cables in a tray must be installed with at least one cable diameter of spacing between them. NEC sets specific size requirements for grounding conductors. 17 / 50 What is the minimum size for single conductors used as equipment grounding conductors in cable trays (392.10(B)(1)(c))? a. 6 AWG. b. No minimum size is specified. c. 4 AWG. d. 2 AWG. Incorrect. The minimum size is 4 AWG. Correct! A minimum size of 4 AWG is required for these conductors. Single conductors used as equipment grounding conductors in cable trays must be at least 4 AWG to ensure sufficient current-carrying capacity. The metal thickness determines the voltage limitation 18 / 50 What is the maximum voltage between conductors for surface metal raceways with a thickness of less than 1.02 mm (0.040 in.) nominal (386.12)? a. No more than 300 volts. b. Any voltage is permitted. c. 300 volts. d. 100 volts. Incorrect. The voltage is limited to 300 volts for raceways with thinner metal. Correct! The voltage must not exceed 300 volts with thinner metal raceways. Surface metal raceways with metal less than 1.02 mm (0.040 in.) nominal thickness cannot be used where the voltage exceeds 300 volts between conductors. Accessibility is critical for safety and maintenance. 19 / 50 What is required for splices and joints in cable trays (392.56)? a. Splices may occupy up to 90% of the tray's cross-sectional area. b. Only factory-made splices are permitted. c. Splices are not allowed in cable trays. d. Splices must be accessible and approved for use in cable trays. Incorrect. Splices must meet accessibility and approval requirements. Correct! Splices must be accessible and approved for use in cable trays. Splices and joints in cable trays must be accessible and approved to ensure compliance and allow for maintenance. Knob-and-tube wiring is a legacy system with limited permitted uses. 20 / 50 Where is the installation of concealed knob-and-tube wiring permitted (394.10)? a. Only in new buildings. b. For extensions of existing installations or by special permission. c. Only in hazardous locations. d. For all wiring methods in attics and hollow walls. Incorrect. Its use is restricted to extensions or with special permission Correct! It is permitted for extensions or by special permission. Concealed knob-and-tube wiring is allowed only for extensions of existing installations or where special permission is granted, as it is no longer widely used in modern installations. Larger conductors are required for ladder cable trays. 21 / 50 What is required when single conductors are installed in a ladder cable tray (392.10(B)(1))? a. Conductors must be 10 AWG or larger. b. Only insulated conductors are allowed. c. A minimum spacing of 6 inches between conductors. d. Conductors must be 1/0 AWG or larger and listed for use in cable trays. Incorrect. Conductors must meet specific size and listing requirements. Correct! 1/0 AWG or larger conductors are required. Single conductors in ladder cable trays must be 1/0 AWG or larger, ensuring safe and compliant installations. Insulators must meet multiple criteria to ensure performance and safety. 22 / 50 What criteria must insulators for outdoor overhead conductors over 1000 volts meet (395.30(C))? a. Ratings for applied phase-to-phase voltage, mechanical strength, and impulse withstand (BIL). b. Only mechanical strength requirements. c. No specific criteria are specified. d. General resistance to weather conditions. Incorrect. Insulators must meet electrical, mechanical, and impulse withstand criteria. Correct! These criteria ensure safe and effective operation of the conductors. Insulators must be rated for the applied phase-to-phase voltage, the mechanical strength needed for the installation, and the impulse withstand BIL, ensuring durability and compliance with high-voltage standards. The NEC specifies conductor types for messenger-supported wiring in industrial settings. 23 / 50 What types of cables are permitted for messenger-supported wiring in industrial establishments (396.10(B))? a. Any cable type listed in NEC Chapter 3. b. Conductors listed in Table 310.4(1) or (2) and medium-voltage cables. c. Nonmetallic cables without additional conditions. d. Only medium-voltage cables. Incorrect. The allowed conductors are listed in Table 310.4(1) or (2) and medium-voltage cables. Correct! Only conductors from Table 310.4(1), (2), or medium-voltage cables are allowed in industrial settings. Messenger-supported wiring in industrial establishments may use any conductor type listed in Table 310.4(1) or (2) or medium-voltage cables. Additional requirements apply for weather and sunlight exposure. NEC mandates provisions for fire safety 24 / 50 How must cable trays be installed when passing through walls or partitions (392.18(D))? a. Only horizontally. b. With removable sections for maintenance. c. In accordance with NEC 300.21 for fire and smoke containment. d. Fully enclosed within the wall. Incorrect. Fire and smoke containment measures are required. Correct! NEC 300.21 applies to cable trays passing through walls. When passing through walls or partitions, cable tray installations must comply with NEC 300.21 to maintain fire and smoke barriers. High-voltage installations require professional engineering oversight. 25 / 50 What documentation is required for the design of overhead conductors over 1000 volts (395.30(A))? a. Engineered design documentation by a licensed professional engineer. b. A standard installation manual. c. No documentation is necessary. d. Only conductor specifications. Incorrect. Engineered design documentation is mandatory for these systems. Correct! A licensed engineer must provide the design documentation. Engineered design documentation by a licensed professional engineer, covering applied voltage, conductor size, support structure spacing, and environmental conditions, must be available upon request to ensure safe and compliant installation. Compatibility prevents corrosion or degradation. 26 / 50 How should cable tray covers be installed for additional protection (392.18(C))? a. Installed only over hazardous areas. b. Made of any available material. c. Required only for indoor installations. d. Compatible with the cable tray material. Incorrect. Covers must match the tray material for compatibility. Correct! Compatibility ensures proper protection and longevity. Cable tray covers must be made of a material that is compatible with the cable tray to ensure durability and protection. Conductor size is crucial for carrying the current safely. 27 / 50 What is the minimum size for load-side utilization conductors (393.100(A))? a. 18 AWG, with exceptions for smaller conductors in specific conditions. b. 14 AWG. c. No minimum size is specified. d. 20 AWG. Incorrect. The minimum conductor size is 18 AWG, with exceptions for smaller Class 2 circuits. Correct! The minimum size is 18 AWG, with smaller conductors allowed under specific conditions. The minimum size for load-side utilization conductors is 18 AWG. However, conductors as small as 24 AWG are permitted for Class 2 circuits if they are fully enclosed and comply with specific conditions. Specific environments pose risks to these systems. 28 / 50 Where is the installation of suspended ceiling power distribution systems prohibited (393.12)? a. In residential buildings. b. For lighting purposes in any location. c. In damp or wet locations, hazardous areas, or concealed spaces. d. In dry locations. Incorrect. These systems cannot be installed in damp, wet, or hazardous locations. Correct! These systems are prohibited in damp, wet, hazardous, or concealed locations. Suspended ceiling power distribution systems are not allowed in damp or wet locations, hazardous (classified) areas, or concealed spaces to ensure compliance with safety standards. The NEC outlines several restrictions for their use. 29 / 50 Where is the use of surface nonmetallic raceways prohibited (388.12)? a. In concealed locations, hazardous areas, or where subject to severe physical damage. b. In office spaces. c. In residential buildings. d. For low-voltage systems. Incorrect. Concealed, hazardous, or high-risk environments are prohibited for these raceways. Correct! These restrictions ensure safe usage of surface nonmetallic raceways. Surface nonmetallic raceways cannot be used in concealed locations, hazardous areas (unless permitted by other articles), or where subject to severe physical damage or ambient temperatures beyond their ratings. NEC mandates secure closure for raceway dead ends. 30 / 50 How must dead ends of underfloor raceways be treated (390.73)? a. Left open for future use. b. Sealed with electrical tape. c. No specific treatment is required. d. Closed to prevent access or entry. Incorrect. Dead ends must be closed to comply with NEC requirements. Correct! Dead ends must be securely closed. Dead ends of underfloor raceways must be securely closed to prevent entry of debris, moisture, or unintended access, ensuring compliance and safety. Certain environments can compromise the integrity and safety of raceways 31 / 50 Where are underfloor raceways prohibited from being installed (390.12)? a. In residential applications. b. In areas with corrosive vapors or in hazardous locations (unless permitted). c. Beneath concrete floors. d. In dry office locations. Incorrect. These environments pose risks and are restricted unless specific conditions are met. Correct! Corrosive and hazardous environments are restricted for underfloor raceways. Underfloor raceways cannot be installed in areas subject to corrosive vapors or in hazardous (classified) locations unless allowed by specific NEC provisions, such as 504.20 and 501.10(B)(3). Nonmetallic raceways are limited to specific environmental conditions. 32 / 50 In what locations are surface nonmetallic raceways permitted (388.10)? a. In dry locations, including through dry walls and partitions if unbroken. b. Only in concealed spaces. c. In hazardous locations. d. Only in outdoor locations. Incorrect. These raceways are restricted to dry locations and specific uses through walls. Correct! They are allowed in dry locations and can pass through unbroken dry walls or partitions. Surface nonmetallic raceways are permitted in dry locations and may extend through dry walls, partitions, and floors if the raceway remains unbroken. Concealment restricts access and violates NEC requirements for strut-type raceways. 33 / 50 Where are strut-type channel raceways prohibited from being installed (384.12)? a. For power pole applications. b. Where concealed. c. In dry locations. d. In areas exposed to sunlight. Incorrect. Concealed installations are not allowed for strut-type channel raceways. Correct! Concealment of strut-type channel raceways is prohibited. Strut-type channel raceways are not permitted where concealed, as they must remain accessible for conductor installation and maintenance. Insulation can compromise heat dissipation and conductor safety. 34 / 50 Where is concealed knob-and-tube wiring prohibited (394.12)? a. In residential buildings. b. In areas where loose, rolled, or foamed-in-place insulation envelops the conductors. c. In unfinished attics. d. In concealed hollow spaces. Incorrect. Wiring is prohibited where insulating material surrounds the conductors. Correct! Insulation enveloping conductors is not allowed for knob-and-tube wiring. Concealed knob-and-tube wiring cannot be used where insulation, such as loose, rolled, or foamed-in-place materials, envelops the conductors. This insulation can trap heat and increase the risk of overheating or fire. Space limitations ensure heat dissipation and safety. 35 / 50 What is the maximum combined cross-sectional area of conductors in underfloor raceways (390.22)? a. 40% of the interior cross-sectional area. b. 50% of the interior cross-sectional area. c. 30% of the interior cross-sectional area. d. No limit applies. Incorrect. The limit for conductors in underfloor raceways is 40%. Correct! Conductors can fill up to 40% of the raceway’s interior crosssectional area. Conductors in underfloor raceways must not exceed 40% of the interior cross-sectional area to comply with NEC requirements and ensure proper heat dissipation. Cable trays are open systems designed to support, not enclose, cables. 36 / 50 What is the primary purpose of a cable tray system (392.1)? a. To replace raceways in all installations. b. To enclose conductors entirely. c. To provide mechanical support for cables and wiring methods. d. For temporary wiring only. Incorrect. Cable trays are used to support, not enclose, wiring. Correct! Cable trays provide mechanical support for cables. Cable trays serve as mechanical support systems for cables and are not raceways as defined in the NEC. Some environments present safety risks for cable tray installations. 37 / 50 Where are cable trays prohibited (392.12)? a. In dry locations. b. In hazardous locations. c. In hoistways or where subject to severe physical damage. d. In industrial facilities. Incorrect. Hoistways and damage-prone areas are not suitable for cable trays. Correct! These restrictions ensure safe use of cable trays. Cable trays are prohibited in hoistways and areas subject to severe physical damage, ensuring safety and compliance. Clearance ensures safety and proper heat dissipation. 38 / 50 What is the minimum clearance required between knob-and-tube conductors and the surfaces they pass over (394.19(A))? a. 25 mm (1 inch). b. No clearance is required. c. 100 mm (4 inches). d. 50 mm (2 inches). Incorrect. The minimum required clearance is 25 mm (1 inch). Correct! The clearance must be at least 25 mm (1 inch). Knob-and-tube wiring requires a minimum clearance of 25 mm (1 inch) between the conductor and the surface it passes over to ensure safe operation and proper heat dissipation. NEC requires grounding for all cable tray systems supporting power conductors. 39 / 50 What grounding requirements apply to metal cable trays (392.60(A))? a. Only aluminum trays require grounding. b. No grounding is required. c. Grounding is optional if non-power cables are used. d. The tray must be grounded as an equipment grounding conductor. Incorrect. Grounding is mandatory for trays supporting electrical conductors. Correct! Grounding is essential for metal cable trays. Metal cable trays must be grounded as an equipment grounding conductor or bonded in compliance with NEC requirements for safety. Concealment is a critical restriction for this wiring method. 40 / 50 Where is open wiring on insulators prohibited (398.12)? a. In agricultural buildings. b. In industrial settings. c. Where concealed by building structures. d. In dry attics. Incorrect. Concealment of open wiring is prohibited by the NEC. Correct! Open wiring cannot be concealed by building structures. Open wiring on insulators cannot be installed where it is concealed by building structures, as it must remain exposed for maintenance and inspection. Marking ensures traceability and compliance with NEC standards. 41 / 50 What marking is required on surface metal raceways (386.120)? a. Clear and durable identification as required by NEC 110.21(A). b. No specific marking is required. c. Manufacturer’s logo only. d. Voltage rating and conductor size. Incorrect. Markings must include clear and durable identification as specified in NEC 110.21(A). Correct! Markings must comply with NEC 110.21(A) for proper identification. Each length of surface metal raceway must be clearly and durably identified as required in the first sentence of NEC 110.21(A), ensuring proper use and installation. Cable fill limitations vary by tray type and conductor size. 42 / 50 What is the maximum allowable fill for multiconductor cables in a solid bottom cable tray (392.22(A)(3))? a. 90% of the tray's width for 4/0 AWG or larger cables. b. 100% of the tray's cross-sectional area. c. 50% of the tray's width. d. No limit applies. Incorrect. The limit is 90% for these specific cables and tray types. Correct! 90% of the tray width is the maximum allowable fill for these cables. For 4/0 AWG or larger cables in a solid bottom tray, the sum of the diameters of all cables must not exceed 90% of the tray width, ensuring proper spacing and heat dissipation. Bus rail conductors must be large enough to safely handle power distribution. 43 / 50 What is the minimum size for power feed bus rail conductors (393.100(B))? a. No size requirement is specified. b. 12 AWG. c. 16 AWG, or equivalent cross-sectional area. d. 18 AWG. Incorrect. The minimum size for power feed bus rail conductors is 16 AWG. Correct! 16 AWG is the minimum required size for these conductors. Power feed bus rail conductors must be at least 16 AWG or have an equivalent crosssectional area for safety and compliance. Specific environments and conditions define where surface metal raceways can be used. 44 / 50 Where is the use of surface metal raceways permitted (386.10)? a. In hazardous locations without restrictions. b. Only for residential installations. c. In dry locations and Class I, Division 2 hazardous locations as specified in NEC 501.10(B)(3). d. Only in wet locations. Incorrect. Surface metal raceways are limited to specific environments as defined by NEC. Correct! Surface metal raceways are allowed in these specified environments. Surface metal raceways are permitted in dry locations and Class I, Division 2 hazardous locations when meeting NEC 501.10(B)(3), and under raised floors as per 645.5(E)(2). These conductors are designed for high-voltage outdoor applications. 45 / 50 Where are outdoor overhead conductors over 1000 volts permitted to be used (395.10)? a. In all locations without restrictions. b. Outdoors in free air for service conductors, feeders, or branch circuits. c. Only for industrial applications. d. Only in residential installations. Incorrect. These conductors are only permitted outdoors in free air for specific applications. Correct! They are allowed outdoors in free air for service conductors, feeders, or branch circuits. Outdoor overhead conductors over 1000 volts are permitted for use outdoors in free air and can serve as service conductors, feeders, or branch circuits, ensuring compliance with high-voltage safety standards. The NEC specifies durable materials for raceway construction. 46 / 50 What materials are permitted for constructing strut-type channel raceways (384.100(A))? a. Nonmetallic materials only. b. Steel, stainless steel, or aluminum. c. Steel, copper, or aluminum. d. Stainless steel, copper, or PVC. Incorrect. Copper and nonmetallic materials are not listed for constructing these raceways. Correct! Steel, stainless steel, and aluminum are the approved materials. Strut-type channel raceways must be made of steel, stainless steel, or aluminum, ensuring strength and corrosion resistance for various applications. Identification ensures safety and proper usage for combination raceways. 47 / 50 What marking is required for combination raceways used for multiple systems (388.70)? a. Different systems must be separated and identified by stamping, imprinting, or color coding. b. Marking is optional if the systems are installed in separate compartments. c. No marking is required for multiple systems. d. Only the voltage rating must be marked. Incorrect. Separation and identification are required for combination raceways. Correct! Compartments must be identified by stamping, imprinting, or color coding. Combination raceways must separate lighting/power circuits from signaling systems and clearly identify the compartments using stamping, imprinting, or color coding. These systems are designed for low-voltage applications. 48 / 50 What is the voltage limit for low-voltage suspended ceiling power distribution systems (393.6(A))? a. 42 volts AC or DC. b. 50 volts AC or DC. c. 30 volts AC or less, or 60 volts DC or less. d. No voltage limit applies. Incorrect. The maximum voltage for these systems is 30 volts AC or 60 volts DC. Correct! These systems are restricted to 30 volts AC or 60 volts DC. Suspended ceiling power distribution systems are limited to operating at 30 volts AC or less and 60 volts DC or less, ensuring safety for Class 2 power levels. Underfloor raceways are designed for use in specific environments. 49 / 50 Where are underfloor raceways permitted to be installed (390.10)? a. Beneath concrete or flooring material, including flush installations in office occupancies. b. In outdoor areas. c. Only in hazardous locations. d. Only in dry locations. Incorrect. Underfloor raceways are specifically permitted under flooring or concrete in the stated conditions. Correct! They are allowed under concrete and flooring and flush installations in offices. Underfloor raceways are permitted beneath the surface of concrete or other flooring materials, and in office occupancies when installed flush with the concrete floor and covered with appropriate flooring. Space must be reserved for heat dissipation and proper wiring. 50 / 50 What is the maximum conductor fill for splices and taps in surface nonmetallic raceways with accessible covers (388.56)? a. 100% of the raceway’s area. b. 75% of the raceway’s area. c. 50% of the raceway’s area. d. No limit applies. Incorrect. Splices and taps can fill up to 75% of the raceway’s crosssectional area. Correct! The maximum fill for splices and taps is 75%. Splices and taps in surface nonmetallic raceways with accessible covers are limited to filling no more than 75% of the raceway’s cross-sectional area to comply with safety standards 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
