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Residential Electrician Ultimate
Exam
Question 1. What does the NEC term “readily accessible” mean? A) Able to be reached without using tools or removing obstacles B) Able to be reached only after removing a panel cover C) Able to be reached only by qualified personnel D) Able to be reached after turning off the power Answer: A Explanation: “Readily accessible” means a component can be accessed without the use of tools, ladders, or removing obstacles, as defined in NEC Article 100. Question 2. In a single-phase 120/240 V residential service, how many ungrounded (hot) conductors are present? A) One B) Two C) Three D) Four Answer: B Explanation: The typical residential service uses two ungrounded conductors (L and L2) each at 120 V to neutral, providing 240 V between them. Question 3. Which formula correctly represents Ohm’s Law? A) V = I / R B) V = I × R C) I = V × R D) R = V – I Answer: B Explanation: Ohm’s Law states voltage equals current multiplied by resistance (V = I·R).
Residential Electrician Ultimate
Exam
Question 4. The NEC requires a minimum working clearance in front of a service disconnecting means. What is the required depth? A) 24 inches B) 30 inches C) 36 inches D) 48 inches Answer: C Explanation: NEC 110.26(A)(1) requires a minimum working space depth of 3 feet (36 inches) in front of equipment. Question 5. When sizing a service-entrance conductor for a 200 A residential service, which factor is NOT considered in Table 310.15(B)(16)? A) Conductor temperature rating B) Number of conductors in the raceway C) Length of the run D) Ambient temperature correction factor Answer: C Explanation: Table 310.15(B)(16) provides ampacity based on temperature rating, number of conductors, and ambient temperature; length is used for voltage-drop calculations, not ampacity. Question 6. A kitchen countertop receptacle must be installed so that no point along the countertop is farther than how many inches from a receptacle? A) 12 inches B) 24 inches C) 36 inches D) 48 inches Answer: B Explanation: NEC 210.52(C)(1) requires receptacles so that no point is more than 24 inches from a receptacle outlet.
Residential Electrician Ultimate
Exam
Explanation: Dual-function GFCI/AFCI breakers protect against ground-faults and arc-faults and are required in many habitable rooms. Question 10. According to NEC 220.12, what is the general lighting load calculation for a dwelling unit? A) 1 VA per square foot B) 2 VA per square foot C) 3 VA per square foot D) 5 VA per square foot Answer: C Explanation: NEC 220.12 specifies a general lighting load of 3 VA per square foot of floor area. Question 11. A residential dryer is rated at 5,000 W. What minimum circuit rating (ampere) is required for this appliance? A) 15 A B) 20 A C) 30 A D) 40 A Answer: C Explanation: 5,000 W ÷ 240 V = 20.8 A; NEC requires a 125 % safety factor, resulting in a minimum of 30 A circuit. Question 12. Which NEC article governs the installation of grounding electrode systems? A) Article 250 B) Article 300 C) Article 210 D) Article 430
Residential Electrician Ultimate
Exam
Answer: A Explanation: Article 250 details grounding and bonding requirements, including grounding electrodes. Question 13. What is the minimum size (in AWG) of a copper grounding electrode conductor (GEC) connected to a 1-phase 200 A service? A) 10 AWG B) 8 AWG C) 6 AWG D) 4 AWG Answer: C Explanation: Table 250.66 indicates a 6 AWG copper GEC is required for a 200 A service. Question 14. In a residential panel, how many circuits may be supplied by a 100 A main breaker without violating the 42-circuit limit? A) 30 B) 40 C) 42 D) 44 Answer: C Explanation: NEC 408.54 limits a panelboard to 42 overcurrent devices regardless of the main breaker size. Question 15. Which of the following is considered a “dwelling unit” under NEC definitions? A) A single-family home with a detached garage B) A two-family duplex sharing a common wall C) A storage shed without living space
Residential Electrician Ultimate
Exam
C) Ground and equipment grounding conductor bonded together D) Only the equipment grounding conductor must be present Answer: B Explanation: In sub-panels, the neutral and equipment grounding conductors must remain isolated; only the main service panel bonds them. Question 19. For a 20 A branch circuit feeding kitchen countertop receptacles, what is the minimum size of the grounding electrode conductor required? A) 14 AWG copper B) 12 AWG copper C) 10 AWG copper D) 8 AWG copper Answer: B Explanation: NEC 250.122 requires a minimum of 12 AWG copper for a 20 A circuit’s grounding conductor. Question 20. Which article of the NEC specifically addresses requirements for tamper-resistant receptacles? A) Article 210 B) Article 406 C) Article 300 D) Article 250 Answer: B Explanation: Article 406 covers receptacles, including the requirement for tamper-resistant receptacles in dwelling units. Question 21. A homeowner wants to install a 240 V electric water heater on a 30 A circuit. What minimum conductor size (copper) should be used, assuming 75 °C insulation? A) 12 AWG
Residential Electrician Ultimate
Exam
B) 10 AWG
C) 8 AWG
D) 6 AWG
Answer: C Explanation: Table 310.16 shows 8 AWG copper at 75 °C rated for 40 A, providing the required 125 % of the 30 A load. Question 22. Which of the following devices is required for a garage that stores gasoline-powered tools? A) GFCI receptacle only B) AFCI breaker only C) Both GFCI and AFCI protection D) No special protection required Answer: C Explanation: NEC 210.12(A) requires AFCI protection in garages, and NEC 210.8(A) (2) requires GFCI protection for receptacles in garages where fuel-powered tools may be used. Question 23. What is the minimum clearance between a service drop and a public walkway? A) 6 feet B) 8 feet C) 10 feet D) 12 feet Answer: C Explanation: NEC 230.9 requires a minimum of 10 feet clearance between service drop conductors and a public walkway. Question 24. In a residential lighting circuit, how many lumens are typically provided per square foot according to common design practice?
Residential Electrician Ultimate
Exam
Question 27. Which NEC article governs the installation of swimming pool equipment? A) Article 680 B) Article 690 C) Article 710 D) Article 750 Answer: A Explanation: Article 680 specifically addresses swimming pools, hot tubs, and related equipment. Question 28. The “6-foot rule” for receptacle placement in a dwelling’s general living area means: A) No point shall be more than 6 feet from a receptacle. B) Receptacles must be installed every 6 feet along the wall. C) Receptacles must be 6 feet above the floor. D) Receptacles must be within 6 feet of a light switch. Answer: A Explanation: NEC 210.52(A)(1) requires that receptacles be placed so that no point along the wall line is farther than 6 feet from a receptacle. Question 29. When performing a box-fill calculation for a device box, which of the following counts as one “unit” of fill? A) A single insulated conductor entering the box B) The internal volume of the box itself C) The metal conduit entering the box D) The external raceway length Answer: A Explanation: NEC 314.16 counts each insulated conductor that terminates or passes through a box as one fill unit.
Residential Electrician Ultimate
Exam
Question 30. For a 120 V, 15 A lighting circuit, what is the maximum number of receptacles allowed on that circuit according to NEC? A) 5 B) 8 C) 10 D) No specific limit, but load must not exceed 80 % of the breaker rating. Answer: D Explanation: NEC does not set a specific receptacle count; the circuit must not exceed 80 % of the breaker’s capacity (12 A continuous load), so the number depends on the connected load. Question 31. Which of the following is a required feature of a listed residential smoke alarm? A) Battery backup not required if hard-wired B) Interconnection capability with other alarms C) Only one alarm per floor is permitted D) Must be installed only in the attic Answer: B Explanation: NEC 760.41 requires hard-wired smoke alarms to be interconnectable so that activation of one triggers all. Question 32. When installing a conduit raceway in a concrete slab, what minimum concrete cover is required for PVC conduit? A) 1 inch B) 2 inches C) 4 inches D) 6 inches Answer: B
Residential Electrician Ultimate
Exam
C) Standard 15 A receptacle D) Surge protective device Answer: B Explanation: NEC 210.8(A)(1) mandates GFCI protection for bathroom receptacles; installing a GFCI receptacle at the first outlet provides this protection. Question 36. What is the required ampacity of a grounding electrode conductor (GEC) for a 100 A service using copper? A) 8 AWG B) 6 AWG C) 4 AWG D) 2 AWG Answer: B Explanation: Table 250.66 lists 6 AWG copper as the minimum size for a 100 A service. Question 37. Which of the following is the correct minimum height for a receptacle outlet installed in a garage? A) 12 inches above the floor B) 18 inches above the floor C) 24 inches above the floor D) No specific height requirement Answer: D Explanation: NEC does not prescribe a specific height for garage receptacles; they must be installed per the general receptacle placement rules. Question 38. A residential feeder runs through a wall cavity with three 4-wire NM-B cables. What is the minimum conduit fill percentage allowed? A) 20 %
Residential Electrician Ultimate
Exam
B) 30 %
C) 40 %
D) 53 %
Answer: C Explanation: For conduit fill with more than two conductors, NEC allows up to 40 % of the conduit’s cross-sectional area. Question 39. Which article of the NEC governs temporary wiring used during construction? A) Article 590 B) Article 590 C) Article 590 D) Article 590 Answer: A Explanation: Article 590 covers temporary installations, including power for construction sites. Question 40. A 20 A branch circuit supplies a bathroom vanity light and a receptacle. What is the maximum continuous load allowed on this circuit? A) 12 A B) 15 A C) 16 A D) 18 A Answer: A Explanation: NEC requires continuous loads not to exceed 80 % of the breaker rating; 80 % of 20 A = 16 A, but the receptacle load is considered continuous, so the lighting plus receptacle must stay under 16 A. The more conservative answer is 12 A (80 % of 15 A) for strictly continuous loads; however, the correct interpretation for a 20 A circuit is 16 A. Therefore the answer is C (16 A). Explanation corrected: 80 % of 20 A = 16 A, which is the maximum continuous load.
Residential Electrician Ultimate
Exam
Explanation: Table 250.66 specifies a 4 AWG copper GEC for a 150 A service when using a concrete-encased electrode. Question 44. Which of the following devices must be installed in a dwelling unit’s outdoor receptacle that is within 6 feet of a swimming pool? A) Standard 15 A receptacle B) GFCI receptacle C) AFCI receptacle D) Weather-proof cover only Answer: B Explanation: NEC 210.8(A)(3) requires GFCI protection for outdoor receptacles in dwelling units. Question 45. A 12 AWG THHN conductor is installed in a raceway with an ambient temperature of 40 °C. What is the corrected ampacity? A) 20 A B) 25 A C) 30 A D) 35 A Answer: B Explanation: Table 310.16 lists 12 AWG THHN at 30 A for 30 °C; applying the 40 °C (10 °C above) correction factor (0.94) reduces ampacity to ~28 A, but the next standard rating is 25 A for safety. Question 46. Which NEC article addresses the installation of luminaires (lighting fixtures) in damp or wet locations? A) Article 410 B) Article 410 C) Article 410 D) Article 410
Residential Electrician Ultimate
Exam
Answer: A Explanation: Article 410 covers luminaires, including requirements for damp and wet locations. Question 47. How many grounding conductors are required in a 3-wire feeder (two hots and a neutral) supplying a sub-panel? A) One B) Two C) Three D) None Answer: A Explanation: A separate equipment grounding conductor is required in addition to the neutral; thus one grounding conductor. Question 48. What is the minimum height for a receptacle installed in a bathroom vanity area? A) 12 inches above the countertop B) 15 inches above the countertop C) 18 inches above the countertop D) No specific height requirement, only location rules apply Answer: D Explanation: NEC does not prescribe a specific height for bathroom vanity receptacles; they must be installed per general receptacle placement rules. Question 49. Which of the following statements about AFCI protection in a dwelling’s bedroom is correct? A) Only a GFCI breaker is required. B) AFCI protection is optional. C) AFCI protection is required on all 120 V branch circuits serving bedroom outlets.
Residential Electrician Ultimate
Exam
A) Article 760 B) Article 300 C) Article 210 D) Article 700 Answer: D Explanation: Article 700 covers emergency systems, including fire alarm wiring for residential occupancies. Question 53. In a residential panel, a 20 A circuit breaker is installed to supply a bathroom exhaust fan. Which additional protection is required by the NEC? A) GFCI protection B) AFCI protection C) Both GFCI and AFCI D) No additional protection required Answer: D Explanation: Bathroom exhaust fans are not considered receptacles or outlets requiring GFCI or AFCI protection. Question 54. What is the minimum size of a copper equipment grounding conductor required for a 60 A feeder? A) 12 AWG B) 10 AWG C) 8 AWG D) 6 AWG Answer: C Explanation: Table 250.122 indicates that a 60 A circuit requires a minimum of 8 AWG copper for the equipment grounding conductor.
Residential Electrician Ultimate
Exam
Question 55. Which of the following is the correct method for securing NM-B cable within 12 inches of a non-metallic box? A) Staple the cable every 6 inches B) Use a cable clamp or listed connector C) Tape the cable to the wall surface D) No securing is required within 12 inches Answer: B Explanation: NEC 334.30 requires NM-B to be secured within 12 inches of a box using a staple, cable clamp, or listed connector. Question 56. In a residential installation, a GFCI receptacle is installed in a kitchen countertop area. Which of the following statements is true? A) The GFCI must be protected by a 20 A breaker only. B) The GFCI provides both ground-fault and arc-fault protection. C) The GFCI must be the first device on the branch circuit. D) The GFCI can be installed downstream of an AFCI breaker. Answer: D Explanation: A GFCI receptacle can be installed downstream of an AFCI breaker; the two protective devices are compatible. Question 57. What is the required minimum height for a receptacle installed in a residential laundry room? A) 12 inches above the floor B) 18 inches above the floor C) 24 inches above the floor D) No specific height requirement, only location rules apply Answer: D Explanation: NEC does not specify a height for laundry room receptacles; they must meet general placement rules.
