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Question 1. Which formula correctly expresses Ohm’s Law? A) V = I × R B) I = V × R C) R = V ÷ I² D) P = V × I Answer: A Explanation: Ohm’s Law states that voltage (V) equals current (I) multiplied by resistance (R). Question 2. In a series circuit of three 10 Ω resistors, the total resistance is: A) 10 Ω B) 20 Ω C) 30 Ω D) 0 Ω Answer: C Explanation: Resistances add in series: 10 Ω + 10 Ω + 10 Ω = 30 Ω. Question 3. For a 120 V, 15 A single‑phase circuit, the apparent power (VA) is: A) 1,800 VA B) 2,000 VA C) 1,500 VA D) 2,400 VA Answer: A Explanation: Apparent power S = V × I = 120 V × 15 A = 1,800 VA. Question 4. Which of the following is a characteristic of a three‑phase, 4‑wire wye system? A) Line voltage equals phase voltage B) Neutral carries no current under balanced load
C) Phase conductors are grounded D) Only three conductors are required Answer: B Explanation: In a balanced wye system, the neutral carries little or no current because the phase currents cancel. Question 5. The temperature correction factor for a copper conductor rated at 75 °C used at 30 °C is: A) 0. B) 1. C) 1. D) 1. Answer: B Explanation: The correction factor is 1.00 when the operating temperature equals the rating temperature; no adjustment needed. Question 6. In an RL circuit, the time constant (τ) is defined as: A) L ÷ R B) R ÷ L C) L × R D) 1 ÷ (R + L) Answer: A Explanation: τ = L / R; it represents the time for current to reach 63.2 % of its final value. Question 7. The power factor of a purely inductive load is: A) 1.0 lagging B) 1.0 leading C) 0.
D) 6 ft Answer: C Explanation: OSHA requires a minimum approach distance of 5 ft for voltages above 600 V. Question 11. Which PPE is mandatory when working on a live 480 V panel? A) Safety glasses only B) Insulated gloves and safety glasses C) Hard hat only D) Ear plugs Answer: B Explanation: Insulated gloves protect against electric shock, and safety glasses protect the eyes from arc flash. Question 12. Lockout/Tagout (LOTO) devices must be: A) Applied only by the supervisor B) Able to withstand the system voltage C) Removed before the equipment is tested D) Visible only to the authorized employee Answer: B Explanation: LOTO devices must be rated for the voltage and energy sources they are securing. Question 13. In NEC terminology, “accessible” means: A) Readily reachable without using tools B) Reachable with tools only C) Only visible, not reachable D) Requires removal of a panel
Answer: A Explanation: “Accessible” means capable of being reached without the use of tools or special equipment. Question 14. The NEC defines “listed” equipment as: A) Approved by the manufacturer only B) Tested and approved by a recognized testing agency C) Installed by a licensed electrician D) Marked with a brand logo Answer: B Explanation: “Listed” means the product has been evaluated and approved by a recognized testing agency such as UL. Question 15. Article 250 requires the equipment grounding conductor (EGC) for a 20 A circuit using 12 AWG copper to be sized at: A) 14 AWG B) 12 AWG C) 10 AWG D) 8 AWG Answer: B Explanation: The EGC must be the same size as the ungrounded conductor for circuits up to 20 A, so 12 AWG is required. Question 16. A grounding electrode system must be bonded to the service‑grounded conductor at which location? A) At the main disconnect only B) At each subpanel C) At the service equipment enclosure D) At the first receptacle
Answer: D Explanation: If the loads are perfectly balanced, the neutral carries no current and may be omitted. Question 20. When calculating feeder ampacity, the adjustment factor for more than three current‑carrying conductors in a raceway is: A) 0.80 for 4‑6 conductors B) 0.70 for 4‑6 conductors C) 0.85 for 4‑6 conductors D) 0.95 for 4‑6 conductors Answer: A Explanation: NEC Table 310.15(B)(3)(a) provides a 0.80 adjustment factor for 4‑6 current‑carrying conductors. Question 21. The NEC permits the use of NM‑B cable in which of the following locations? A) Wet basements B) Outdoor conduit C) Within a finished wall cavity of a dry interior D) In a raceway exposed to sunlight Answer: C Explanation: NM‑B (Romex) is allowed in dry, interior locations such as finished wall cavities. Question 22. The maximum fill for a conduit that contains three 4 AWG THHN conductors is: A) 40 % of the conduit’s cross‑sectional area B) 45 % C) 53 % D) 60 % Answer: A
Explanation: For more than two conductors, the conduit fill must not exceed 40 % of the internal area. Question 23. Which article of the NEC governs the installation of fire alarm circuits? A) 210 B) 300 C) 760 D) 800 Answer: C Explanation: Article 760 covers fire alarm systems, including wiring methods and power supplies. Question 24. A GFCI protected receptacle in a kitchen must be installed where? A) Only at the countertop B) At all countertop receptacles C) Only for appliances over 1500 W D) Only in the pantry Answer: B Explanation: NEC 210.8(A)(6) requires GFCI protection for all receptacles serving countertop surfaces in dwelling units. Question 25. AFCI protection is required for which of the following circuits in a new residence? A) Bedroom lighting circuits B) Bathroom fan circuits C) Garage receptacle circuits D) All of the above Answer: A Explanation: NEC 210.12(A) requires AFCI protection for all 120‑V, single‑phase, 15‑ and 20‑A branch circuits supplying bedroom outlets.
A) Protect the motor from short circuits B) Limit the in‑rush current C) Disconnect the motor on sustained overload conditions D) Provide a ground‑fault path Answer: C Explanation: Overload relays detect excessive current over time and open the circuit to protect the motor. Question 30. In a three‑phase, 4‑wire system, the neutral conductor must be identified by: A) White or gray insulation B) Green insulation C) Red insulation D) Any color as long as it is marked Answer: A Explanation: NEC 200.6 requires the grounded (neutral) conductor to be identified by white or gray (or by distinctive marking). Question 31. The minimum size of a grounding electrode conductor (GEC) for a 100 A service using copper is: A) 12 AWG B) 10 AWG C) 8 AWG D) 6 AWG Answer: C Explanation: NEC Table 250.66 indicates an 8 AWG copper GEC is required for a 100 A service. Question 32. A “readily accessible” location for a disconnecting means is defined as: A) Within 6 ft of the equipment
B) Capable of being reached without the use of tools or removing obstacles C) Visible from the exterior of the building D) Located on the same floor as the equipment Answer: B Explanation: “Readily accessible” means it can be reached without tools, ladders, or removing obstacles. Question 33. Which of the following is NOT an allowed method for grounding a metal conduit system? A) Using a grounding clamp at each box B) Relying on the conduit’s continuity alone C) Installing a grounding wire inside the conduit D) Bonding the conduit to the service equipment Answer: B Explanation: While metal conduit can serve as an equipment grounding conductor, it must be bonded at each connection point; relying solely on continuity is insufficient. Question 34. The ampacity of a 75 °C rated 4‑AWG aluminum conductor is: A) 55 A B) 65 A C) 70 A D) 85 A Answer: B Explanation: NEC Table 310.15(B)(16) lists 4‑AWG AL at 75 °C with an ampacity of 65 A. Question 35. When installing a raceway in a concrete slab, the minimum cover to the top of the conduit is: A) ½ in.
B) Any bathroom receptacle C) Only for hair‑dryers D) Only for electric shavers Answer: B Explanation: All bathroom receptacles must be GFCI protected per NEC 210.8(A)(1). Question 39. A “service disconnect” must be located: A) Inside the building only B) Within the building or on the outside of the building C) Only at the utility meter base D) Within 10 ft of the service entrance Answer: B Explanation: NEC 230.71 permits the service disconnect to be either inside or outside the building. Question 40. The minimum rating for a feeder breaker supplying a 60 A feeder is: A) 50 A B) 60 A C) 70 A D) 80 A Answer: B Explanation: The breaker must be sized to protect the feeder; the smallest standard rating not less than the calculated load is 60 A. Question 41. Which article of the NEC addresses the installation of liquid‑tight flexible conduit (LFMC)? A) 320 B) 330 C) 340
D) 352
Answer: C Explanation: Article 340 covers Liquid‑tight Flexible Metal Conduit (LFMC) and its installation requirements. Question 42. The purpose of a “pull box” in a conduit system is to: A) Provide a junction for splicing conductors B) Allow conductors to be pulled through bends C) Serve as a grounding point D) Reduce voltage drop Answer: B Explanation: Pull boxes provide a location where conductors can be accessed and pulled around bends or changes in direction. Question 43. When using a multi‑wire branch circuit (MWBC) with a shared neutral, the ungrounded conductors must be: A) On the same phase B) On opposite phases (different legs) C) Of the same gauge only D) Protected by a GFCI only Answer: B Explanation: To cancel neutral current, the two hot conductors must be on opposite phases (180° apart) in a MWBC. Question 44. The minimum height for a receptacle installed in a garage is: A) 12 in. above the floor B) 18 in. above the floor C) 24 in. above the floor
D) 60 A
Answer: C Explanation: Standard method: 8 kW for the range + 3 kW for small‑appliance circuits = 11 kW. At 240 V, I = 11,000 W / 240 V ≈ 45.8 A. Rounded up to the next standard breaker size → 50 A. Question 48. In a commercial kitchen, the demand factor for the total cooking equipment load is: A) 100 % B) 75 % C) 60 % D) 50 % Answer: C Explanation: NEC Table 220.55 allows a 60 % demand factor for the total cooking equipment load in a commercial kitchen. Question 49. The minimum conduit size for a 3‑phase, 4‑wire feeder using 4/0 AWG aluminum conductors is: A) 1‑in. EMT B) 1‑¼‑in. EMT C) 1‑½‑in. EMT D) 2‑in. EMT Answer: C Explanation: 4/0 AL has a large diameter; NEC Chapter 9 Table 1 indicates 1‑½‑in. EMT is required to accommodate the conductors and maintain fill limits. Question 50. Which of the following is a permissible use for a “metallic raceway” as an equipment grounding conductor? A) As the sole grounding path for a detached garage panel B) As a grounding path only when the conduit is continuous and bonded at each end
C) Only when the conduit is PVC D) Never permissible Answer: B Explanation: Metal conduit can serve as an equipment grounding conductor if it is continuous and bonded at each termination. Question 51. The NEC requires a minimum of how many disconnecting means for a 600 A service? A) One B) Two C) Three D) Four Answer: B Explanation: NEC 230.71 requires at least two disconnecting means for services rated over 600 A. Question 52. Which type of grounding electrode is NOT permitted for a residential grounding system? A) Concrete‑encased electrode (Ufer) B) Ground rod C) Metal water pipe not bonded to the system D) Ground ring Answer: C Explanation: A metal water pipe can be used only if it is in direct contact with the earth for at least 10 ft and is bonded; otherwise it is not an acceptable electrode. Question 53. For a 120 V, 20 A receptacle circuit in a dwelling, the maximum continuous load allowed is: A) 16 A B) 18 A
C) 5 %
D) 10 %
Answer: B Explanation: NEC recommends a maximum of 3 % voltage drop for feeders and branch circuits combined. Question 57. Which of the following devices is required to be installed on all 125‑V, 15‑ and 20 ‑A receptacles in a garage? A) AFCI B) GFCI C) Surge protector D) None Answer: B Explanation: NEC 210.8(A)(2) mandates GFCI protection for garage receptacles. Question 58. A “locked‑in” conduit fitting is used to: A) Prevent the conduit from being removed without a tool B) Secure the conduit to a wall surface C) Provide a grounding path D) Reduce conduit vibration Answer: A Explanation: Locked‑in fittings require a special tool to release, preventing unauthorized removal. Question 59. The NEC defines “wet location” as: A) Any location exposed to rain only B) Any location with a relative humidity above 80 % C) An area subject to moisture, condensation, or water intrusion, including outdoors and underground
D) Only locations submerged in water Answer: C Explanation: “Wet location” includes any area where moisture is present, such as outdoors, underground, or within concrete. Question 60. For a 30 kW, 480 V three‑phase motor, the NEC recommends a short‑circuit protective device (SCPD) rating of: A) 150 % of full‑load current B) 200 % of full‑load current C) 250 % of full‑load current D) 300 % of full‑load current Answer: B Explanation: NEC 430.32 requires the SCPD to be sized at 200 % of the motor’s full‑load current for inverse‑time circuit breakers. Question 61. In a fire‑alarm system, the Class A power‑limiting circuit must be protected by a: A) 20‑A breaker B) 30‑A breaker C) 15‑A breaker D) 10‑A breaker Answer: C Explanation: NEC 760.41 requires Class A circuits to be protected by a 15‑A overcurrent device unless otherwise calculated. Question 62. The minimum conduit size for a 3‑wire, 4‑AWG copper service entrance cable is: A) ½‑in. EMT B) ¾‑in. EMT C) 1‑in. EMT
