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Question 1. Which of the following equations correctly represents Ohm’s Law? A) P = V × I B) V = I ÷ R C) V = I × R D) I = V ÷ P Answer: C Explanation: Ohm’s Law states that voltage (V) equals current (I) multiplied by resistance (R). Question 2. In a purely resistive circuit, the power factor is: A) 0. B) 0. C) 1. D) Undefined Answer: C Explanation: Resistive loads have voltage and current in phase, giving a power factor of 1.0. Question 3. The temperature coefficient of resistance for copper is approximately: A) +0.00393 /°C B) - 0.00393 /°C C) +0.00039 /°C D) 0 /°C Answer: A Explanation: Copper’s resistance increases with temperature at about +0.00393 per degree Celsius. Question 4. According to NEC Article 100, the term “equipment grounding conductor” is defined as:
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A) A conductor that carries load current under normal conditions. B) A conductor that provides a low-impedance path to ground for fault current. C) A conductor used only for signal transmission. D) A conductor that isolates the circuit from earth. Answer: B Explanation: The EGC is intended to safely carry fault current back to the source. Question 5. The NEC hierarchy of authority places which of the following documents at the highest level? A) Manufacturer’s instructions B) Local amendments C) National Electrical Code (NEC) D) UL listings Answer: C Explanation: The NEC is the primary code; local amendments may modify it, but the NEC remains the foundation. Question 6. When determining the minimum size of a service-entrance conductor, which factor is NOT considered? A) Maximum demand load B) Voltage drop C) Ambient temperature correction D) Color of the conductor insulation Answer: D Explanation: Conductor color is irrelevant to sizing; demand, voltage drop, and temperature are required factors. Question 7. The minimum clearance required between an overhead service-drop conductor and a building roof edge is: A) 3 ft B) 5 ft
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Answer: C Explanation: NEC recommends a maximum of 3 % voltage drop for feeders and branch circuits combined. Question 11. Which type of protection is required for a bathroom receptacle in a dwelling unit? A) GFCI only B) AFCI only C) Both GFCI and AFCI D) Neither Answer: A Explanation: NEC 210.8(A)(1) mandates GFCI protection for bathroom receptacles. Question 12. An AFCI is required in which of the following residential locations? A) Garage B) Bedroom C) Basement D) All of the above Answer: D Explanation: NEC 210.12 requires AFCI protection for all 120 V, single-phase branch circuits supplying outlets in bedrooms, garages, and basements. Question 13. The minimum number of receptacles required in a living room of 20 ft × 15 ft is: A) 2 B) 3 C) 4 D) 5 Answer: C Explanation: NEC 210.52(A) requires one receptacle per wall space of 12 ft or less; this room needs at least four.
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Question 14. The grounding electrode conductor (GEC) for a 100-A residential service may be sized as which of the following? A) #8 AWG copper B) #6 AWG copper C) #4 AWG copper D) #2 AWG copper Answer: B Explanation: Table 250.66 permits #8 AWG copper for up to 100 A only if a single rod is used; the typical minimum is #6 AWG copper. Question 15. Which of the following is NOT an approved grounding electrode? A) Ufer (concrete-encased) electrode B) Metal water pipe not bonded to the system C) Ground rod D) Ground plate Answer: B Explanation: A metal water pipe must be bonded; an unbonded pipe cannot serve as a grounding electrode. Question 16. The minimum size of the equipment grounding conductor (EGC) for a 20-A branch circuit with copper conductors is: A) #14 AWG B) #12 AWG C) #10 AWG D) #8 AWG Answer: B Explanation: NEC Table 250.122 specifies #12 AWG copper for a 20-A circuit. Question 17. Bonding of interior metal water piping is required at:
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B) 0.
C) 0.
D) 0.
Answer: B Explanation: Table 310.15(B)(2)(a) gives a factor of 0.91 for 40 °C ambient temperature for 90 °C insulation. Question 21. Which of the following cable types is suitable for direct burial without a conduit? A) NM-B (Romex) B) AC (Armored Cable) C) UF (Underground Feeder) D) MC (Metal-Clad) Answer: C Explanation: UF cable is rated for direct burial in the earth. Question 22. The maximum number of #12 AWG THHN conductors that may be installed in a 1/2-in. EMT conduit is: A) 6 B) 9 C) 12 D) 15 Answer: B Explanation: Using the 40 % fill rule and the cross-sectional area of #12 THHN, nine conductors fit in 1/2-in. EMT. Question 23. For a 3-wire feeder supplying a 240-V, 30-A circuit, the minimum conduit size required (EMT) is: A) 1/2-in. B) 3/4-in.
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C) 1-in. D) 1-1/4-in. Answer: A Explanation: The conduit fill for three #10 AWG THHN conductors fits within 1/2-in. EMT. Question 24. Which of the following is a requirement for a junction box in a wet location? A) Must be metal only B) Must be listed for wet locations C) Must be larger than 4 in³ D) Must be installed on a wall only Answer: B Explanation: NEC 314.15 requires boxes in wet locations to be listed for such use. Question 25. The minimum height above finished floor for a receptacle in a dwelling’s kitchen countertop is: A) 12 in. B) 15 in. C) 18 in. D) 24 in. Answer: C Explanation: NEC 210.52(C)(1) requires receptacles to be installed not more than 20 in. above the countertop; 18 in. is a common practice. Question 26. A swimming pool pump motor must be provided with which of the following over-current protection? A) Standard circuit breaker only B) Dedicated GFCI breaker only C) Dedicated circuit breaker sized per motor’s full-load amps D) No over-current protection required
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Explanation: NEC 422.31 requires the disconnect to be readily accessible and as close as practicable to the equipment. Question 30. Which over-current device is appropriate for protecting a 5-hp, 240 - V single-phase motor with a full-load current of 14 A? A) 15-A standard circuit breaker B) 20-A inverse-time circuit breaker C) 30-A standard circuit breaker D) 10-A fuse Answer: B Explanation: Motors require inverse-time breakers sized 125– 250 % of full-load current; a 20-A breaker is suitable. Question 31. The required PPE for an electrician working on a live 480-V panel includes: A) Safety glasses only B) Hard hat and steel-toe boots only C) Arc-rated face shield, gloves, and flame-resistant clothing D) No PPE if the panel is de-energized Answer: C Explanation: OSHA and NFPA 70E require arc-rated PPE when working on energized equipment above 240 V. Question 32. The minimum approach distance for an arc-flash boundary of 4 cal/cm² is: A) 4 in. B) 12 in. C) 24 in. D) 48 in. Answer: C
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Explanation: NFPA 70E defines the arc-flash boundary distance where the incident energy is 4 cal/cm²; for typical systems this is about 24 in. Question 33. Lockout/Tagout (LOTO) procedures require that the lock applied to a disconnecting means be: A) Standard padlock only B) Identical to the one used by the employer C) Unique to the authorized employee and not removable by others D) Colored red only Answer: C Explanation: LOTO requires a lock that only the authorized employee can remove to ensure safety. Question 34. When trenching for underground service conductors, the minimum cover depth for a residential feeder in non-rock soil is: A) 12 in. B) 18 in. C) 24 in. D) 30 in. Answer: B Explanation: NEC 300.5(D) requires a minimum of 18 in. cover for residential feeders in non-rock. Question 35. OSHA regulation 29 CFR 1926.501(b)(1) requires that ladders used on construction sites be: A) Maximum 6 ft in length B) Inspected before each shift C) Only wooden ladders allowed D) Equipped with anti-slip feet only Answer: B
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Question 39. Under Oklahoma lien law, a contractor must file a lien affidavit within how many days after completing work? A) 30 days B) 45 days C) 60 days D) 90 days Answer: B Explanation: Oklahoma statutes require filing a lien affidavit within 45 days of completion. Question 40. The “fine schedule” of the Oklahoma Construction Industries Board (CIB) primarily addresses: A) Electrical design standards B) Penalties for violations of licensing rules C) Material specifications for construction D) Tax rates for contractors Answer: B Explanation: The CIB fine schedule lists monetary penalties for breaches of licensing and regulatory requirements. Question 41. Which of the following is the correct method to calculate conduit fill for mixed-size conductors? A) Add the areas of the largest conductor only B) Use the sum of the cross-sectional areas of all conductors and compare to 40 % of conduit’s internal area C) Multiply the number of conductors by the area of the smallest conductor D) Ignore insulation thickness Answer: B Explanation: NEC requires the total cross-sectional area of all conductors (including insulation) to be ≤ 40 % of conduit’s internal cross-sectional area.
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Question 42. A 4-wire feeder to a subpanel must have which of the following conductor arrangements? A) Two hots, one neutral, one ground B) Three hots and one neutral C) Two hots and two neutrals D) One hot, one neutral, two grounds Answer: A Explanation: A 4-wire feeder supplies two ungrounded (hot) conductors, a grounded (neutral) conductor, and an equipment grounding conductor. Question 43. The NEC requires that the neutral conductor of a multi-wire branch circuit be: A) Labeled “neutral” only B) Connected to the ground at every outlet box C) Simultaneously disconnected with all ungrounded conductors D) Never larger than the hot conductors Answer: C Explanation: NEC 210.4(B) mandates a common disconnect for all ungrounded conductors of a MWBC, ensuring the neutral is also disconnected. Question 44. When installing NM-B cable in a wall cavity, the maximum spacing between staples is: A) 4 in. B) 6 in. C) 8 in. D) 12 in. Answer: B Explanation: NEC 334.30 requires NM cable to be secured at intervals not exceeding 6 in. and within 12 in. of a box.
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Question 48. A conduit run that passes through a fire-rated wall assembly must be: A) Unprotected, as conduit is fire-resistant B) Sealed with firestop material to maintain the wall’s rating C) Lined with additional metal pipe D) Installed only with PVC conduit Answer: B Explanation: NEC 300.21 requires firestopping any penetrations through fire-rated assemblies. Question 49. The NEC permits the use of a single-pole breaker to protect a 240 - V, 2-wire motor circuit only if: A) The motor has a built-in thermal overload B) The breaker is rated at twice the motor’s full-load amps C) The circuit also supplies 120-V loads D) The motor is less than 5 hp Answer: A Explanation: A motor with a built-in overload can be protected by a single-pole breaker if the overload trips at the appropriate current. Question 50. The required height for a receptacle in a garage to be considered “readily accessible” is: A) No higher than 48 in. above the floor B) No higher than 54 in. above the floor C) No higher than 72 in. above the floor D) No height limit, only location matters Answer: B Explanation: NEC 210.52(G) sets the maximum height for garage receptacles at 48 in.; however, “readily accessible” generally means not more than 54 in. from the floor.
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Question 51. The maximum number of receptacles allowed on a single 20-A branch circuit in a dwelling unit is: A) 8 B) 10 C) 12 D) No specific limit, but must not exceed the circuit’s ampacity Answer: D Explanation: NEC does not set a numeric limit; the number of receptacles is limited by the load calculation and ampacity. Question 52. Which of the following statements about GFCI protection for outdoor receptacles is correct? A) Only required for receptacles within 6 ft of a sink B) Required for all outdoor receptacles regardless of location C) Only required for receptacles serving a pool pump D) Not required if the receptacle is on a dedicated 30-A circuit Answer: B Explanation: NEC 210.8(A)(3) requires GFCI protection for all outdoor receptacles in dwellings. Question 53. An equipment grounding conductor may be installed in a raceway that also contains: A) Only power conductors, no neutrals B) Both power and neutral conductors C) Only signal conductors D) No other conductors; it must be separate Answer: B Explanation: The EGC can share the same raceway with other circuit conductors, provided the conduit fill limits are observed.
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Question 57. When installing a grounding electrode conductor (GEC) that runs outdoors, the conductor must be: A) Underground only B) Exposed and painted green C) Protected from physical damage, e.g., in conduit or buried with proper cover D) Only attached to the service equipment Answer: C Explanation: NEC 250.68(A) requires the GEC to be protected from physical damage. Question 58. The minimum size of copper grounding electrode conductor for a 400 - A service is: A) #6 AWG B) #4 AWG C) #2 AWG D) #1/0 AWG Answer: D Explanation: Table 250.66 indicates #1/0 AWG copper is required for a 400-A service. Question 59. The NEC requires that a disconnecting means for a PV array be installed: A) Inside the photovoltaic inverter only B) At the service equipment or as a separate disconnect within sight of the array C) Only at the utility meter D) No disconnect required for residential PV Answer: B Explanation: NEC 690.13 requires a disconnect for PV systems to be readily accessible and within sight of the array.
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Question 60. Which of the following is true regarding the use of a “dedicated” circuit for a laundry dryer? A) It may share a circuit with a bathroom GFCI receptacle B) It must be a 30-A, 240-V circuit with a dedicated breaker C) It can be a 20-A, 120-V circuit if the dryer is electric D) No dedicated circuit required if the dryer is gas-fired Answer: B Explanation: NEC 210.11(C)(2) requires a dedicated 30-A, 240-V circuit for electric dryers. Question 61. The maximum number of current-carrying conductors allowed in a single conduit without applying derating is: A) 3 B) 4 C) 6 D) 9 Answer: A Explanation: NEC Table 310.15(B)(3)(a) applies derating when more than three current-carrying conductors are present. Question 62. A metal conduit that is used as an equipment grounding conductor must be: A) Bonded at each end with a listed bonding device B) Grounded only at the service panel C) Connected to the neutral at every box D) Never used as a grounding path Answer: A Explanation: NEC 250.118 allows metal raceways to serve as EGCs when bonded at each end.
