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Electrician2020 Ultimate Exam
Question 1. Which law states that the sum of currents entering a junction equals the sum of currents leaving that junction? A) Ohm’s Law B) Kirchhoff’s Current Law C) Faraday’s Law D) Thevenin’s Theorem Answer: B Explanation: Kirchhoff’s Current Law (KCL) governs the conservation of charge at a node, requiring the algebraic sum of currents to be zero. Question 2. In a single-phase AC circuit, the apparent power (VA) is 1200 VA and the real power (W) is 960 W. What is the power factor? A) 0.80 lagging B) 0.80 leading C) 1.25 lagging D) 1.25 leading Answer: A Explanation: Power factor = real power / apparent power = 960 W ÷ 1200 VA = 0.80. Since the circuit is inductive, it is lagging. Question 3. According to NEC Article 100, “readily accessible” means: A) Capable of being reached without the use of tools or a ladder B) Capable of being reached with a ladder only C) Capable of being reached only after removing a panel D) Capable of being reached after opening a conduit Answer: A Explanation: “Readily accessible” refers to equipment that can be reached quickly without tools, ladders, or removing obstacles. Question 4. Which instrument is safest to use for measuring voltage on a live circuit? A) Ammeter B) Ohmmeter
Electrician2020 Ultimate Exam
C) Voltmeter with a high-impedance input D) Clamp-on ammeter Answer: C Explanation: A voltmeter is designed for voltage measurement and presents a high impedance, minimizing circuit disturbance and shock risk. Question 5. A 240 V, 20 A branch circuit supplies a heater. What is the minimum conductor size (copper) required by Table 310.16 for 75 °C insulation? A) 12 AWG B) 10 AWG C) 8 AWG D) 6 AWG Answer: B Explanation: For 20 A at 75 °C, Table 310.16 calls for 12 AWG, but a heater is a continuous load (125 %). 20 A × 1.25 = 25 A, requiring 10 AWG (30 A rating). Question 6. In a multi-wire branch circuit (MWBC) feeding two 120 V circuits, how must the ungrounded conductors be arranged? A) Both on the same phase of the service B) On opposite phases (line-to-line) C) One grounded and one ungrounded D) Grounded to the neutral only Answer: B Explanation: MWBCs must have the two hot conductors on opposite phases to provide a 240 V potential and allow neutral cancellation. Question 7. The NEC requires a GFCI receptacle in a residential garage for circuits of up to which amperage? A) 15 A only B) 20 A only C) 15 A and 20 A D) All amperages Answer: C
Electrician2020 Ultimate Exam
standard rating, which is 35 A. However, many jurisdictions require the next standard size, so answer B (35 A) is correct. Question 11. Which of the following is an acceptable grounding electrode under NEC 250.50? A) Metal water pipe in contact with the earth for at least 18 in. B) A concrete-encased electrode (Ufer) of at least 20 ft of #4 rebar C) A ground rod driven 4 ft into the ground D) All of the above Answer: D Explanation: NEC 250.50 lists metal water pipe, concrete-encased electrode, and ground rods (minimum 8 ft) as acceptable grounding electrodes. Question 12. The minimum size of a grounding electrode conductor (GEC) for a 100-A service using copper is: A) #10 AWG B) #8 AWG C) #6 AWG D) #4 AWG Answer: B Explanation: NEC Table 250.66 indicates #8 AWG copper for a 100-A service. Question 13. When bonding a metal water pipe system, the connection must be made within how many feet of the point where the pipe enters the building? A) 5 ft B) 10 ft C) 25 ft D) No distance limit Answer: B Explanation: NEC 250.104(A)(1) requires bonding within 5 ft of the point of entry; however, many authorities adopt a 10-ft limit for practicality. The correct answer per NEC is 5 ft, but the exam often uses 5 ft. (Thus answer A.)
Electrician2020 Ultimate Exam
Question 14. In a conduit system, the maximum allowable fill for three or more conductors in EMT is: A) 15 % B) 20 % C) 30 % D) 40 % Answer: B Explanation: NEC Chapter 9, Table 1, allows 40 % fill for one conductor, 31 % for two, and 40 % for three or more in raceways; however, for EMT the limit is 40 % for three or more. (Thus answer D.) Question 15. A 4-in. schedule 40 PVC conduit is used to protect a 4-wire feeder in a wet location. According to NEC, the conduit must be: A) Listed for wet locations only B) Listed for both wet and dry locations C) Unlisted, as PVC is inherently wet-rated D) Lined with a moisture barrier Answer: B Explanation: PVC conduit is listed for both wet and dry locations; no additional lining is required. Question 16. For a junction box containing three conductors rated 20 A each, what is the minimum internal volume required (in cubic inches) according to NEC Table 314.16(B)? A) 30 in³ B) 45 in³ C) 60 in³ D) 75 in³ Answer: B Explanation: Each 20-A conductor (14 AWG) counts as 2.25 cu in. Three conductors = 6.75 cu in. Add 2.25 cu in. for the equipment (ground). Minimum box = 2 × (6.75+2.25)=18 cu in. (But NEC provides a minimum of 30 cu in for three 14-AWG conductors. Thus answer A.)
Electrician2020 Ultimate Exam
A) 6 in. B) 12 in. C) 18 in. D) 24 in. Answer: B Explanation: NEC 300.5(A)(1) requires a minimum cover of 12 in. for PVC conduit under driveways. Question 21. The ampacity of a 12-AWG copper THHN conductor at 90 °C is 30 A. If it is installed in a raceway with 5 current-carrying conductors, what is the corrected ampacity? A) 30 A B) 27 A C) 24 A D) 21 A Answer: C Explanation: Table 310.15(B)(3)(a) gives a 80 % derating factor for 4- 6 conductors. 30 A × 0.80 = 24 A. Question 22. Which of the following flexible cords is permitted for use as a fixed branch-circuit wiring method? A) SJT (Service-Junior-Thermoplastic) B) SE (Service-Entrance) cable C) UF (Underground Feeder) cable D) None of the above Answer: D Explanation: Flexible cords are not permitted as a permanent wiring method for branch circuits per NEC 400.10. Question 23. A luminaire installed in a bathtub “zone 0” must have a rating of: A) 120 V, 15 A, listed for damp locations B) 120 V, 15 A, listed for wet locations C) 250 V, 15 A, listed for wet locations
Electrician2020 Ultimate Exam
D) 250 V, 15 A, listed for dry locations Answer: C Explanation: NEC 410.10(D) requires luminaires in “zone 0” (inside the tub) to be listed for wet locations and rated up to 250 V. Question 24. An electric dryer requires a disconnecting means. Which of the following satisfies NEC requirements? A) A standard 20-A breaker in the main panel B) A dedicated 30-A double-pole breaker with a tie-handle C) A fused disconnect box located within 6 ft of the dryer D) Both B and C are acceptable Answer: D Explanation: NEC 422.31 allows a dedicated circuit breaker or a fuse disconnect within sight distance (6 ft) of the appliance. Question 25. For a three-phase induction motor rated 15 hp, 460 V, 3-phase, 60 Hz, what is the minimum size (copper) of the branch-circuit conductors per NEC Table 430.250? A) 8 AWG B) 6 AWG C) 4 AWG D) 2 AWG Answer: C Explanation: NEC Table 430.250 lists #4 AWG copper for a 15-hp motor at 460 V. Question 26. A motor’s overload protection must be set to protect the motor at a current not greater than: A) 115 % of full-load amps (FLA) B) 125 % of FLA C) 150 % of FLA D) 200 % of FLA Answer: B Explanation: NEC 430.32 requires overload protection to be set between 115 % and 125 % of the motor’s full-load current.
Electrician2020 Ultimate Exam
Question 30. In a healthcare facility, patient-care areas must have a grounding system that provides a low-impedance path to ground. Which NEC article addresses this requirement? A) 210. B) 250. C) 517. D) 645. Answer: C Explanation: NEC 517.19 requires a grounding system for patient-care areas to ensure a low-impedance path. Question 31. The required distance between a pool’s bonding grid and the nearest GFCI receptacle is: A) 6 ft B) 10 ft C) 12 ft D) 15 ft Answer: C Explanation: NEC 680.22(A)(2) requires GFCI protection for receptacles within 12 ft of the pool’s water’s edge. Question 32. For a sign-mounted luminaire, the disconnecting means must be located within how many feet of the sign? A) 5 ft B) 10 ft C) 15 ft D) 20 ft Answer: B Explanation: NEC 410.136 requires a disconnect within sight distance, not exceeding 10 ft, of the sign. Question 33. A photovoltaic (PV) array requires a rapid-shutdown device. The device must be capable of reducing the conductors to less than what voltage within 30 seconds?
Electrician2020 Ultimate Exam
A) 30 V
B) 60 V
C) 80 V
D) 100 V
Answer: B Explanation: NEC 690.12 requires rapid-shutdown to reduce voltage to 30 V (for residential) or 80 V (for commercial). For the 2020 code, the requirement is 30 V for residential, but the exam often uses 80 V as the threshold for all. Thus answer B. Question 34. An emergency lighting circuit must be supplied from an emergency source that is: A) Connected to the same panel as normal lighting B) Fed through a transfer switch that isolates it from normal power C) Powered by a battery backup only D) Fed through a dedicated branch circuit with no transfer switch Answer: B Explanation: NEC 700.12 requires emergency lighting to be supplied from an emergency source that is isolated from normal power. Question 35. Which type of communication cable must be bonded to the grounding electrode system at each end? A) Unshielded twisted pair (UTP) B) Shielded twisted pair (STP) C) Coaxial cable D) Fiber-optic cable Answer: B Explanation: NEC 800.10 requires the shield of STP cable to be bonded at each end to the grounding system. Question 36. A radio antenna lead-in conductor is required to be protected by a lightning-rod system. The required grounding electrode conductor size for a 50 - A service is: A) #12 AWG copper
Electrician2020 Ultimate Exam
Explanation: OSHA requires a minimum clearance of 10 ft for voltages over 50 kV, but for 15 kV the minimum is 10 ft. However, many jurisdictions use 10 ft as the standard clearance for any line above 50 V. (Thus answer B.) Question 40. Double-insulated tools are identified by which symbol? A) A green triangle B) A yellow square with a black dot C) The double-square symbol (two overlapping squares) D) A red circle with a line through it Answer: C Explanation: The double-insulated symbol is two overlapping squares, indicating the tool does not require a grounding conductor. Question 41. A 120-V, 20-A receptacle in a bathroom must be GFCI protected because: A) All bathroom receptacles are required to be GFCI protected B) Only receptacles within 3 ft of a sink need GFCI C) Only 15-A receptacles need GFCI D) GFCI is optional in bathrooms Answer: A Explanation: NEC 210.8(A)(1) mandates GFCI protection for all 125-V, single-phase, 15- and 20-amp receptacles in bathrooms. Question 42. When sizing an equipment grounding conductor (EGC) for a 60 - A circuit using copper, the minimum size per NEC Table 250.122 is: A) #12 AWG B) #10 AWG C) #8 AWG D) #6 AWG Answer: B Explanation: Table 250.122 lists #10 AWG copper for a 60-A circuit.
Electrician2020 Ultimate Exam
Question 43. The NEC permits the use of aluminum conductors for feeders up to what voltage rating without special considerations? A) 120 V B) 240 V C) 600 V D) 1000 V Answer: C Explanation: Aluminum conductors are permitted for feeders rated 600 V or less per NEC 310.15(B)(1). Question 44. A conduit body (C-type) must have a minimum volume equal to: A) The sum of the volumes of all conductors entering it B) Twice the volume of the largest conductor inside C) The volume of the largest conduit body listed in Table 314. D) The volume of the conduit body as specified by the manufacturer Answer: D Explanation: NEC 314.28 requires using the manufacturer’s listed volume for conduit bodies. Question 45. For a 3-phase, 4-wire feeder supplying a commercial building, the neutral conductor must be: A) Same size as the ungrounded conductors B) One size larger than the ungrounded conductors C) Minimum #8 AWG regardless of load D) Sized based on the calculated neutral load per 220. Answer: D Explanation: NEC 220.61 requires neutral sizing based on calculated neutral load, not automatically the same size as the ungrounded conductors. Question 46. The minimum burial depth for a 1-in. Schedule 80 PVC conduit in a residential driveway is: A) 12 in. B) 18 in.
Electrician2020 Ultimate Exam
Explanation: Current = 1500 W ÷ 120 V = 12.5 A. For a continuous load, multiply by 125 % = 15.6 A → next standard breaker is 20 A. Question 50. In a Class II hazardous location, the wiring method must be: A) Intrinsically safe only B) Non-explosive and listed for the specific division C) Any NM cable is acceptable D) Rigid metal conduit only Answer: B Explanation: NEC 511.3 requires wiring methods in Class II locations to be listed for the specific division (e.g., Division 1 or 2). Question 51. The NEC requires that a receptacle installed in a swimming pool’s “shallow water” zone be GFCI protected and have a maximum rating of: A) 15 A, 125 V B) 20 A, 250 V C) 30 A, 250 V D) 50 A, 250 V Answer: B Explanation: NEC 680.22(A) permits 20-A, 250-V GFCI receptacles in the shallow-water zone. Question 52. A sign-mounted luminaire requires a disconnecting means. Which device can serve this purpose? A) A standard panel-mount circuit breaker located in the building B) A pull-type disconnect located within 5 ft of the sign C) A fused disconnect located in the sign’s enclosure D) Both B and C are acceptable Answer: D Explanation: NEC 410.136 allows either a pull-type or a fused disconnect within sight distance of the sign. Question 53. For a PV system with a DC-rated voltage of 600 V, the required labeling must include:
Electrician2020 Ultimate Exam
A) The system’s AC voltage only B) The maximum DC voltage, inverter rating, and shutdown instructions C) Only the manufacturer’s name and model number D) No labeling is required for systems under 1000 V Answer: B Explanation: NEC 690.11 requires DC systems to be labeled with maximum DC voltage, inverter rating, and rapid-shutdown instructions. Question 54. In an emergency power system, the transfer switch must be: A) A manual switch only B) Listed for automatic operation and have a minimum rating of 125 % of the load C) Rated for at least 150 % of the connected load D) Installed outside the building for easy access Answer: B Explanation: NEC 700.12 requires an automatic transfer switch rated for at least 125 % of the emergency load. Question 55. The NEC permits the use of NM-B cable in a commercial building’s interior walls provided the building is: A) More than three stories tall B) Classified as a Type V occupancy C) A one-family dwelling only D) A non-hazardous occupancy up to three stories Answer: D Explanation: NM-B is allowed in non-hazardous occupancies up to three stories per NEC 334.10. Question 56. When installing a conduit system in a wet location, the conduit must be: A) Uncoated steel only B) Listed for wet locations (e.g., PVC, EMT) C) Painted with a waterproof coating
Electrician2020 Ultimate Exam
A) Capable of being reached without removing obstacles or using tools B) Capable of being reached with the use of a ladder or a stool C) Capable of being reached after removing a panel or cover D) Capable of being reached only by qualified personnel Answer: C Explanation: “Accessible” means capable of being reached without removing any part of the building structure or equipment, but it may require tools. Question 61. A 250-V, 15-A receptacle in a garage must be protected by a GFCI. Which of the following devices can provide this protection? A) A two-pole 20-A breaker without GFCI B) A GFCI receptacle installed at the point of use C) A regular receptacle with a ground-fault interrupter (GFI) upstream D) Both B and C are acceptable Answer: D Explanation: Both a GFCI receptacle at the outlet or a GFCI breaker upstream satisfy NEC 210.8(A)(2). Question 62. When using a multimeter to test for continuity, the device must be set to the: A) Voltage range B) Resistance (Ω) range C) Current (A) range D) Frequency (Hz) range Answer: B Explanation: Continuity testing uses the resistance (Ω) setting, which often provides an audible beep when resistance is low. Question 63. The NEC permits the use of a single-pole breaker to protect a 120/240-V multi-wire branch circuit only if: A) The breaker has a common trip mechanism B) The breaker is a GFCI type C) The circuit does not contain a neutral conductor
Electrician2020 Ultimate Exam
D) The breaker is rated at 30 A or higher Answer: A Explanation: MWBCs must have a common trip or handle-tied breakers for the two hot legs. Question 64. The minimum size of a copper grounding electrode conductor for a 400-A service is: A) #4 AWG B) #2 AWG C) #1/0 AWG D) #2/0 AWG Answer: D Explanation: Table 250.66 lists #2/0 AWG copper for a 400-A service. Question 65. Which of the following is a correct statement about the use of MC cable? A) It may be installed in exposed, damp locations without additional protection B) It must be run in conduit at all times C) It is permitted for outdoor use only if listed for sunlight exposure D) It can replace EMT in all applications Answer: A Explanation: MC cable is listed for exposed, damp, and wet locations when properly installed per NEC 320. Question 66. The NEC requires that a grounding electrode system be bonded to the building’s structural steel. This is accomplished by: A) Connecting a #10 AWG copper wire to the nearest steel beam B) Using a bonding jumper sized per Table 250. C) Installing a separate grounding rod for the steel D) No bonding is required for structural steel Answer: B Explanation: Bonding jumpers must be sized according to Table 250.66 and connect the grounding electrode to structural steel.
