eep April 10, 2025 NEC 400-490 NEC Quizzes Report a question What’s wrong with this question? You cannot submit an empty report. Please add some details. 0% Article 400-490 Part04 This quiz consists of 50 carefully selected questions covering NEC Articles 400 through 490, which provide critical guidelines for flexible cords and cables (Article 400), switchgear and control equipment (Article 409), and installations operating above 1000 volts (Article 490). These sections of the National Electrical Code focus on safety, material specifications, and proper installation practices. The randomly generated questions ensure a thorough assessment of your understanding, reinforcing key principles related to permitted uses of flexible cords, ampacity ratings, industrial control panels, and high-voltage equipment requirements. Some topics may reappear in different contexts to strengthen comprehension and application. Your feedback is invaluable! If you notice any discrepancies or have suggestions for improvement, please report them. Your insights help maintain the accuracy and effectiveness of this learning tool. The scope of this article includes most low-voltage switching devices. 1 / 50 What does NEC Article 404 primarily cover (404.1)? a. Temporary switching devices. b. Switches operating at 1000 volts or below, unless referenced for higher voltages. c. Only switches above 1000 volts. d. Wireless control equipment. Incorrect. The article focuses on low-voltage switches, not wireless or temporary systems. Correct! Article 404 applies to switches at 1000 volts or below. Article 404 governs switches, switching devices, and circuit breakers operating at 1000 volts or below, excluding wireless control equipment. NEC restricts these cables in certain structural installations. 2 / 50 In what scenarios are portable power feeder cables over 2000 volts prohibited (400.43)? a. When run through walls, ceilings, or floors. b. In industrial applications. c. For connection to portable equipment. d. When used for temporary installations. Incorrect. Running through walls, ceilings, or floors is prohibited. Correct! Running cables through walls, ceilings, or floors is not allowed. These cables cannot be run through walls, ceilings, or floors, as such installations pose safety risks. NEC mandates specific protection for transformer-fed panelboards. 3 / 50 What is required for panelboards supplied through a transformer (408.36(B))? a. Overcurrent protection must be on the transformer’s secondary side. b. No additional protection is required. c. A dedicated panelboard for each transformer. d. Primary side protection is sufficient. Incorrect. Secondary-side protection is required by NEC. Correct! Overcurrent protection must be on the transformer’s secondary side. Overcurrent protection must be located on the secondary side of a transformer feeding a panelboard unless exceptions apply NEC requires measures to minimize fire risk. 4 / 50 What must be provided for panelboards installed over combustible floors (408.17)? a. A fire-resistant enclosure. b. Clearance of at least 3 feet from the floor. c. Suitable protection, such as a sheet of noncombustible material. d. Nothing additional is required. Incorrect. A protective, noncombustible layer is required. Correct! Noncombustible material protects against fire hazards. Combustible floors must have protection, such as a sheet of noncombustible material, to prevent fire risks. NEC specifies standards for installations in damp or wet locations. 5 / 50 What marking is required for switchboards in damp locations (408.16)? a. No marking is needed. b. They must be marked as compliant with NEC 312.2. c. A general weatherproof label. d. Voltage rating only. Incorrect. Markings must indicate compliance with NEC 312.2 Correct! Compliance with NEC 312.2 is required. Switchboards in damp locations must comply with NEC 312.2, ensuring suitable construction and labeling. These cables are designed for portable or temporary applications. 6 / 50 Where are portable power feeder cables over 2000 volts permitted (400.42)? a. For connecting portable equipment and machinery or wiring cranes and hoists. b. For installations in hazardous locations. c. For fixed wiring of structures. d. Where run through floors or ceilings. Incorrect. These cables are for portable or machinery connections only. Correct! They are permitted for portable equipment and machinery connections. These cables are allowed for connecting portable equipment, machinery, cranes, and hoists but not for fixed wiring or structural installations. The splice must maintain the cord’s original safety features. 7 / 50 How must splices in flexible cords be performed (400.13)? a. Splices must retain insulation and mechanical properties. b. Splices are not permitted. c. With electrical tape only. d. With wire nuts and heat shrink only. Incorrect. Splices must maintain all original properties of the cord. Correct! Splices must preserve the cord’s insulation and mechanical properties. Splices must be done in a way that retains the insulation, outer sheath properties, and usage characteristics of the flexible cord, ensuring safety and compliance. The scope defines the type of equipment and voltage range covered. 8 / 50 What is the scope of NEC Article 409 (409.1)? a. It applies to residential control panels. b. It applies to panels operating above 1000 volts. c. It applies exclusively to motor control centers. d. It applies to industrial control panels operating at 1000 volts or below. Incorrect. The article focuses on industrial panels at 1000 volts or less. Correct! The scope includes industrial control panels operating at 1000 volts or below. NEC Article 409 covers industrial control panels designed for general use and operating at 1000 volts or below, aligning with UL 508A standards. Exposed live parts have strict location and access requirements. 9 / 50 What is required for switchboards and switchgear with exposed live parts (408.20)? a. They are prohibited in industrial settings. b. They must be enclosed in plastic. c. They must be located in permanently dry areas and accessible only to qualified persons. d. No restrictions apply if supervised. Incorrect. Such equipment is limited to dry areas and qualified access. Correct! Installation and access restrictions ensure safety for exposed live parts. Switchboards and switchgear with exposed live parts must be installed in permanently dry locations and restricted to qualified personnel to ensure safety. Labels ensure clear identification of system characteristics. 10 / 50 What labeling is required for ungrounded DC systems (408.3(F)(4))? a. A general warning for all systems. b. No labeling is required. c. CAUTION: UNGROUNDED DC SYSTEM OPERATING — _____ VOLTS BETWEEN CONDUCTORS. d. Voltage rating only. Incorrect. Specific labels for ungrounded systems are required. Correct! The labeling ensures clear identification of ungrounded systems. Ungrounded DC systems must have specific cautionary labels to indicate their operating voltage and configuration. Vertical operation has standard positions for clarity. 11 / 50 What is the required handle position for vertically operated switches (404.7)? a. Vertical for "off." b. Either position is acceptable. c. Horizontal for "on." d. Up for "on" and down for "off." Incorrect. Vertically operated switches must follow standard positions. Correct! Up is “on,” and down is “off” for vertical switches. For vertically operated switches, the “up” position must correspond to the “on” state, and the “down” position must correspond to “off” for proper indication. Splices must maintain the integrity of the cable. 12 / 50 What types of connectors must be used for splicing portable power feeder cables rated over 600 volts (400.36)? a. Temporary clamp splices. b. Electrical tape and heat shrink tubing. c. Standard wire nuts. d. Permanent molded or vulcanized splices. Incorrect. Only permanent molded or vulcanized splices are allowed. Correct! Splices must meet strict durability requirements. Splices must be permanent molded or vulcanized types to ensure that the cable retains its insulation and usage properties. Specific spaces have inherent safety concerns for switches. 13 / 50 Where are switches prohibited from being installed (404.4(C))? a. In attics. b. Outdoors without enclosures. c. Within tub or shower spaces, unless part of a listed assembly. d. In bedrooms. Incorrect. Tub or shower spaces restrict standard switch installations. Correct! Switches cannot be installed in these spaces unless listed for the purpose. Switches are prohibited in tub or shower spaces unless they are part of a listed tub or shower assembly. NEC mandates specific methods to identify grounded conductors. 14 / 50 What is required to identify grounded conductors in flexible cords (400.22)? a. No specific identification is needed. b. Continuous white or gray marking, or surface ridges. c. Yellow insulation for grounding. d. A red stripe on the insulation. Incorrect. The conductor must be identified with white, gray, or surface ridges. Correct! NEC specifies white, gray, or surface ridges for identification. Grounded conductors in flexible cords must have continuous white or gray insulation or markings like ridges to distinguish them from ungrounded conductors. The NEC ensures that dimmers are properly protected against overcurrent to prevent damage or unsafe conditions. 15 / 50 Where dimmers are installed in ungrounded conductors, each dimmer shall have overcurrent protection not greater than _______________ of the dimmer rating and shall be disconnected from all ungrounded conductors when the master or individual switch or circuit breaker supplying such dimmer is in the open position. a. 125 percent b. 110 percent c. 120 percent d. 115 percent Incorrect! The NEC specifies that dimmers must have overcurrent protection not exceeding 125 percent of their rated load, per NEC Article 404.14(E). Correct! Overcurrent protection for dimmers installed in ungrounded conductors must not exceed 125 percent of the dimmer rating, as stated in NEC Article 404.14(E). 125 percent: According to NEC 404.14(E), overcurrent protection for dimmers must not exceed 125 percent of their rated load to ensure safety and compliance. Other percentages like 110%, 115%, and 120% are not aligned with the NEC requirements for dimmer overcurrent protection. Overcurrent protection ensures safety by preventing damage. 16 / 50 What is required for the overcurrent protection of panelboards (408.36)? a. A protective device with a rating not exceeding the panelboard’s rating. b. No overcurrent protection is required. c. Overcurrent devices are optional for service equipment. d. Only if rated below 200 amperes. Incorrect. Overcurrent protection is mandatory and must match or be below the panelboard’s rating. Correct! The overcurrent device must not exceed the panelboard’s rating. Panelboards must be protected by an overcurrent device rated at or below the panelboard’s rating to prevent overloading and damage. Clearance reduces fire risks in installations. 17 / 50 What clearance is required between a switchboard and a combustible ceiling (408.18(A))? a. 3 feet unless a noncombustible shield is used. b. No clearance is needed. c. 6 inches. d. 2 feet for industrial installations. Incorrect. A 3-foot clearance or a shield is mandatory. Correct! Clearance or shielding ensures fire safety Switchboards require a 3-foot clearance from combustible ceilings unless a noncombustible shield is installed. Markings provide critical information for proper switch application. 18 / 50 What marking is required on switches per NEC (404.20(A))? a. Current, voltage, and horsepower ratings. b. Installation location. c. Only the voltage rating. d. Manufacturer’s logo. Incorrect. Switches require markings for current, voltage, and horsepower. Correct! Markings ensure proper application of switches. Switches must be marked with their current, voltage, and horsepower ratings to ensure they are used within their designed capabilities. Clearance ensures safe installation and operation. 19 / 50 What is the minimum clearance for conductor entry in bus enclosures (408.5)? a. No specific clearance is required. b. 3 inches for insulated busbars. c. 6 inches for non-insulated busbars. d. 8 inches for insulated and 10 inches for non-insulated busbars. Incorrect. The correct clearances are 8 inches for insulated and 10 inches for non-insulated busbars. Correct! These clearances ensure safe operation. Conductor entry clearance must be at least 8 inches for insulated busbars and 10 inches for non-insulated busbars. Cords in these locations must withstand wear and tear. 20 / 50 What types of cords are permitted in show windows and showcases (400.15)? a. Any flexible cord. b. Only heat-resistant cords. c. Only types suitable for dry locations. d. Hard or extra-hard usage cords, such as Type S or SO. Incorrect. Hard or extra-hard usage cords are required for these environments. Correct! Cords must be suitable for hard or extra-hard usage. Only cords identified for hard or extra-hard usage are allowed in show windows and showcases due to their exposure to damage. Openings must be closed to prevent access to live parts. 21 / 50 How must unused openings in panelboards and switchgear be handled (408.7)? a. Closed using identified closures or approved means. b. Covered with temporary materials. c. Left open for ventilation. d. Covered with tape. Incorrect. Openings cannot be left open or temporarily covered. Correct! Identified closures must be used. Unused openings must be closed with identified closures or equivalent approved means to maintain the enclosure’s integrity. Certain switch types are not allowed to be reconditioned. 22 / 50 What is prohibited regarding reconditioned switches (404.16)? a. Reconditioning is always permitted. b. Reconditioning of lighting, dimmer, and snap switches. c. Reconditioning of knife switches only. d. Reconditioning of switches rated above 600 volts. Incorrect. Reconditioning is not permitted for these types of switches. Correct! Reconditioning is prohibited for lighting, dimmer, and snap switches. The NEC prohibits reconditioning of lighting switches, dimmer switches, and snap switches, ensuring reliability and safety. Protection prevents damage to the cord. 23 / 50 How should flexible cords be protected when passing through holes in covers or enclosures (400.17)? a. By wrapping the cords with heat shrink tubing. b. By using electrical tape. c. With bushings or fittings. d. No protection is required. Incorrect. Bushings or fittings are required to protect the cords. Correct! Bushings or fittings are mandatory for this protection. Flexible cords must be protected with bushings or fittings when passing through holes to prevent physical damage and maintain insulation integrity. These switches must operate on ungrounded conductors for safety. 24 / 50 How must three-way and four-way switches be wired (404.2(A))? a. In the grounded circuit conductor. b. In the ungrounded circuit conductor. c. Using any available conductor. d. Only in conduit systems. Incorrect. Switching must occur in the ungrounded conductor only. Correct! Switching is performed in the ungrounded circuit conductor. Three-way and four-way switches must perform switching in the ungrounded conductor to maintain compliance and safety. Grounding conductors must be easily identifiable. 25 / 50 What is required for equipment grounding conductors in flexible cords (400.23)? a. Must be red or yellow for safety. b. Must always be green. c. Must be continuously marked in green or green with yellow stripes. d. Must be continuously marked in green or green with yellow stripes. Incorrect. The conductor must be marked in green or green with yellow stripes. Correct! These markings are mandatory for equipment grounding conductors. Equipment grounding conductors must have a continuous green color or green with yellow stripes to ensure proper identification. The scope defines the type of equipment and voltage range covered. 26 / 50 What is the scope of NEC Article 409 (409.1)? a. It applies to residential control panels. b. It applies to industrial control panels operating at 1000 volts or below. c. It applies exclusively to motor control centers. d. It applies to panels operating above 1000 volts. Incorrect. The article focuses on industrial panels at 1000 volts or less. Correct! The scope includes industrial control panels operating at 1000 volts or below. NEC Article 409 covers industrial control panels designed for general use and operating at 1000 volts or below, aligning with UL 508A standards. NEC specifies orientation restrictions for safety. 27 / 50 Are panelboards allowed to be installed in a face-up position (408.43)? a. Only for temporary installations. b. Yes, if in residential buildings. c. No, face-up or face-down installation is prohibited. d. Yes, with proper ventilation. Incorrect. Face-up and face-down installations are prohibited. Correct! This orientation is not allowed for panelboards. Panelboards cannot be installed in a face-up or face-down position to avoid debris and moisture ingress. Fault current marking ensures the equipment can handle expected faults. 28 / 50 What is required for short-circuit current rating marking (408.6)? a. Marking is optional for residential panelboards. b. It must match the panelboard’s voltage rating. c. The fault current and calculation date must be marked on the enclosure. d. Only fault current needs to be listed. Incorrect. Both fault current and calculation date are required. Correct! Marking includes fault current and calculation date. Switchboards, switchgear, and panelboards must be marked with the available fault current and the date the calculation was performed to confirm adequacy. NEC provides multiple requirements for cable connectors. 29 / 50 What is required for connectors used to join portable power feeder cables in a run (400.35)? a. All of the above. b. Connectors must prevent disconnection while energized. c. Suitable means must eliminate tension at connectors. d. Connectors must lock or latch firmly together. Incorrect. All these requirements apply to cable connectors. Correct! Connectors must meet all these NEC requirements. Connectors must meet all the above criteria to ensure safety, secure connections, and prevention of accidental disconnections while energized. NEC prioritizes protection and stability for conductors and busbars. 30 / 50 What is required for conductors and busbars in switchgear and panelboards (408.3(A)(1))? a. They must be located at the top of the enclosure. b. They must be insulated regardless of voltage. c. They must be free from physical damage and firmly held in place. d. No specific requirements are outlined. Incorrect. Conductors and busbars must meet these protection and stability requirements. Correct! Conductors and busbars must be free from damage and firmly secured. Conductors and busbars must be free from physical damage and securely held in place to ensure safe operation. Metal components must be grounded to prevent electrical hazards. 31 / 50 How must snap switches with metal faceplates be grounded (404.9(B))? a. They must be connected to an equipment grounding conductor. b. By ensuring the faceplate is securely mounted. c. By attaching the switch to a wooden backplate. d. Grounding is not required for switches with metal faceplates. Incorrect. Grounding is required for safety with metal faceplates. Correct! Metal faceplates must be connected to an equipment grounding conductor. Snap switches with metal faceplates must connect to an equipment grounding conductor to ensure safety in case the faceplate becomes energized. Markings help identify cable type and usage. 32 / 50 How often must flexible cords and cables be marked with their type designation and other required information (400.6)? a. Marking is optional for flexible cords. b. Only at both ends. c. Every 12 inches. d. Every 24 inches. Incorrect. The markings must appear every 24 inches Correct! Markings are required at 24-inch intervals. Flexible cords and cables must be marked on the surface at intervals not exceeding 24 inches with the type designation, size, and other required details. The NEC specifies the minimum allowable conductor size for flexible cords. 33 / 50 What is the minimum size of flexible cords for overcurrent protection (400.16)? a. 22 AWG. b. 20 AWG. c. 18 AWG. d. 14 AWG. Incorrect. 18 AWG is the smallest allowed conductor size for overcurrent protection. Correct! 18 AWG is the minimum size required. Flexible cords must be at least 18 AWG in size for overcurrent protection. Smaller cords may only be used if approved for specific appliances. Flexible cords are designed for temporary and portable applications. 34 / 50 What is the primary purpose of flexible cords and cables as defined in Article 400 (400.1)? a. To secure high-voltage connections for long-term use. b. To connect equipment to outlets via plugs or direct connections. c. For permanent installations in walls or ceilings. d. To replace fixed wiring methods. Incorrect. These cords are not a replacement for fixed wiring methods. Correct! Flexible cords connect equipment to outlets. Flexible cords and cables are primarily used to connect equipment to outlets using a cord-and-plug connection or through a direct connection to an outlet box, as specified in NEC. Flexible cables must not be bent too tightly. 35 / 50 What is the minimum bending radius for portable power feeder cables rated from 2000 to 5000 volts (400.47)? a. Six times the cable diameter. b. No minimum bending radius is specified. c. Eight times the cable diameter. d. Two times the cable diameter. Incorrect. The minimum radius is six times the cable diameter. Correct! The bending radius must be six times the cable diameter. For cables rated 2000 to 5000 volts, the minimum bending radius is six times the outer diameter of the cable to prevent damage during installation. Voltage and equipment type are key to the scope of this article. 36 / 50 What is the scope of Article 408 (408.1)? a. Applies to all electrical equipment. b. Applies only to residential installations. c. Applies exclusively to industrial applications. d. Applies to switchboards, switchgear, and panelboards operating at 1000 volts or below. Incorrect. The scope applies to specified equipment at 1000 volts or below. Correct! The article applies to this equipment and voltage range. Article 408 covers switchboards, switchgear, and panelboards operating at 1000 volts or below unless referenced for higher voltages. Supply conductor sizing accounts for continuous loads and motor operation. 37 / 50 What must the ampacity of industrial control panel supply conductors be (409.20)? a. 100% of the full-load current. b. Equal to the panel's rated current. c. 125% of the full-load current of heating loads plus 125% of the largest motor's full-load current, plus the sum of other connected loads. d. No specific ampacity is required. Incorrect. The NEC requires specific calculations for supply conductor ampacity. Correct! Supply conductor ampacity is calculated based on these load factors. The ampacity of supply conductors must account for heating loads at 125%, the largest motor at 125%, and all other connected loads, ensuring proper operation under full load. Grounding ensures safety for all conductive parts. 38 / 50 How must panelboards be grounded (408.40)? a. The cabinet and frame must be connected to an equipment grounding conductor. b. Grounding is optional. c. Only neutral conductors must be grounded. d. Grounding is required only for metallic enclosures. Incorrect. Grounding applies to both the cabinet and frame. Correct! Both the cabinet and frame must be grounded. Panelboard cabinets and frames must be connected to an equipment grounding conductor, ensuring proper grounding. NEC explicitly addresses reconditioned equipment. 39 / 50 Are reconditioned panelboards allowed (408.2(A))? a. No, reconditioned panelboards are not permitted. b. Yes, with proper labeling. c. No restrictions apply. d. Yes, if inspected by a qualified technician. Incorrect. Reconditioned panelboards are prohibited. Correct! Reconditioned panelboards are not permitted. Panelboards cannot be reconditioned under any circumstances to ensure safety and reliability. NEC specifies individual terminals for safety and maintenance. 40 / 50 How must grounded conductors terminate in a panelboard (408.41)? a. Each conductor must terminate in an individual terminal unless marked otherwise. b. Multiple conductors per terminal are allowed. c. Grounding conductors do not need separate terminals. d. Grounded and ungrounded conductors can share terminals. Incorrect. NEC requires separate terminals unless otherwise identified. Correct! Grounded conductors must terminate individually. Each grounded conductor must terminate in its own terminal to ensure safe and clear isolation during troubleshooting. Grounded conductors are essential for certain lighting controls. 41 / 50 What is required for switches controlling lighting loads in generalpurpose branch circuits (404.2(C))? a. A grounded circuit conductor at the switch location, with exceptions. b. A dedicated breaker for each switch. c. A dedicated ground rod for each circuit. d. Two independent switch locations. Incorrect. A grounded conductor is required unless exceptions are met. Correct! A grounded conductor must be available unless an exception applies. A grounded circuit conductor must be extended to the switch location unless specific exceptions apply, such as the use of a raceway or automatic lighting control. Gravity closure is a potential safety concern for knife switches. 42 / 50 How should single-throw knife switches be installed (404.6(A))? a. With blades always energized. b. In any orientation. c. Only in weatherproof enclosures. d. So gravity will not close them unless approved for inverted use. Incorrect. The switch must be installed to avoid unintended closure. Correct! Gravity closure must be prevented unless specifically approved. Single-throw knife switches must be positioned to prevent gravity from closing them unless they are approved for inverted use with mechanical means to hold them open. Overcurrent device limits ensure the panelboard’s safe operation. 43 / 50 How are maximum overcurrent devices in a panelboard determined (408.54)? a. By the manufacturer’s discretion. b. By the panelboard’s design, rating, and listing. c. Based on the total amperage rating of the panelboard. d. By the largest branch circuit breaker size. Incorrect. Device limits are set by the panelboard’s design and listing. Correct! Panelboards must not exceed their listed capacity for overcurrent devices. The number of overcurrent devices must not exceed what the panelboard is designed, rated, and listed for. NEC specifies insulation materials for durability and safety. 44 / 50 What type of insulation must flexible cords have (400.21)? a. No insulation is required. b. Only thermoplastic. c. Rubber only. d. Thermoset or thermoplastic. Incorrect. Only thermoset or thermoplastic insulation is allowed. Correct! Thermoset or thermoplastic insulation is required. Flexible cords must use thermoset or thermoplastic insulation to meet safety and durability standards. Circuit descriptions must be clear to avoid confusion. 45 / 50 How should circuits in a panelboard be identified (408.4(A))? a. Using employee names. b. With general terms like "lights" or "outlets." c. With a permanent, clear, and specific description. d. Identification is optional. Incorrect. Vague or transient identifiers are not allowed. Correct! Clear, specific, and permanent descriptions are required. Circuits must have permanent, specific descriptions that are unlikely to cause confusion, ensuring clarity and safety. Supply conductor sizing accounts for continuous loads and motor operation. 46 / 50 What must the ampacity of industrial control panel supply conductors be (409.20)? a. 100% of the full-load current. b. No specific ampacity is required. c. Equal to the panel's rated current. d. 125% of the full-load current of heating loads plus 125% of the largest motor's full-load current, plus the sum of other connected loads. Incorrect. The NEC requires specific calculations for supply conductor ampacity. Correct! Supply conductor ampacity is calculated based on these load factors. The ampacity of supply conductors must account for heating loads at 125%, the largest motor at 125%, and all other connected loads, ensuring proper operation under full load. These cords are not suitable for installations where they pass through structural elements. 47 / 50 Where is the use of flexible cords explicitly prohibited (400.12)? a. Where run through holes in walls, ceilings, floors, or windows. b. For temporary applications. c. In residential garages. d. In industrial settings. Incorrect. Running cords through walls, ceilings, or floors is prohibited. Correct! Such installations are restricted under NEC. Flexible cords are prohibited where they pass through holes in walls, structural ceilings, or floors, or through doorways and windows, to prevent damage and ensure safety. NEC sets specific voltage limits to prevent hazards between devices. 48 / 50 What is the voltage limitation between adjacent snap switches in enclosures without barriers (404.8(B))? a. No voltage limitation applies. b. 300 volts. c. 120 volts. d. 480 volts. Incorrect. The voltage limit without barriers is 300 volts. Correct! The limit is 300 volts unless barriers are used. Snap switches in the same enclosure must not have a voltage exceeding 300 volts between adjacent devices unless barriers are installed to prevent contact. Consistent arrangement minimizes confusion and ensures safety 49 / 50 What phase arrangement is required for 3-phase AC busbars (408.3(E) (1))? a. C, A, B. b. A, B, C from front to back, top to bottom, or left to right. c. No specific arrangement is required. d. B, C, A. Incorrect. The standard arrangement is A, B, C. Correct! The proper arrangement is A, B, C. AC phase arrangement on 3-phase buses must follow the A, B, C order unless an exception applies, such as for additions to existing installations. Clear marking is critical for high-leg identification. 50 / 50 How must high-leg identification be marked on switchboards (408.3(F) (1))? a. Voltage rating only. b. With a red triangle. c. CAUTION: _____ PHASE HAS _____ VOLTS TO GROUND. d. A warning label is optional. Incorrect. The high-leg must be clearly marked with phase and voltage. Correct! NEC requires this specific labeling for high-leg identification. High-leg identification must include a caution label specifying the phase and voltage to ground, preventing misconnection. 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
