Download PrepIQ Alabama AL NASCLA National Journey level Electrician Learning Course Ultimate Exam and more Exams Technology in PDF only on Docsity!
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Question 1. Which NEC article governs the requirements for grounding electrode systems? A) Article 210 B) Article 250 C) Article 300 D) Article 430 Answer: B Explanation: Article 250 of the NEC contains the rules for grounding and bonding, including the grounding electrode system. Question 2. Under OSHA 29 CFR 1926.416, what is the minimum distance a worker must maintain from an energized line of 15 kV or less? A) 6 ft B) 10 ft C) 15 ft D) 20 ft Answer: B Explanation: For voltages of 15 kV or less, OSHA requires a minimum 10-foot approach distance unless the line is insulated or protected. Question 3. In a three-phase, four-wire wye system, the line-to-neutral voltage is 120 V. What is the line-to-line voltage? A) 120 V B) 208 V C) 240 V D) 277 V Answer: B Explanation: Line-to-line voltage = √ 3 × line-to-neutral → √ 3 × 120 V ≈ 208 V.
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Question 4. Which symbol on an electrical blueprint represents a single-pole, normally-open (SPNO) switch? A) ⎔ B) ⏚ C) ⎓ D) ⎔ with a slash Answer: C Explanation: The standard symbol for an SPNO switch is a single straight line with a break, depicted as “⎓”. Question 5. A motor starter includes a thermal overload that trips at 115 % of full-load current. If the motor’s full-load current is 30 A, at what current will the overload trip? A) 30 A B) 34.5 A C) 38 A D) 45 A Answer: B Explanation: 115 % × 30 A = 34.5 A; the overload is designed to protect the motor at this level. Question 6. According to NFPA 70E, what is the “restricted approach boundary” for an unqualified person working on a system with an arc-flash incident energy of 8 cal/cm²? A) 3 ft B) 4 ft C) 6 ft D) 8 ft Answer: C
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Explanation: Article 210.8(A) lists the locations in dwellings where GFCI protection is mandatory. Question 10. When using a multimeter to measure 120 V AC, which setting should be selected? A) DC voltage B) AC voltage C) Resistance D) Continuity Answer: B Explanation: To measure alternating voltage, the AC voltage setting must be used. Question 11. A feeder has a calculated load of 80 A. Which standard breaker size is the smallest that can be used without exceeding the 125 % rule for continuous loads? A) 80 A B) 90 A C) 100 A D) 110 A Answer: C Explanation: 80 A × 125 % = 100 A; the next standard size is 100 A. Question 12. In a residential wiring diagram, a “S” inside a circle denotes which device? A) Switch B) Receptacle C) Smoke detector D) Sensor Answer: A Explanation: The “S” symbol within a circle is the standard notation for a switch.
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Question 13. Which of the following is NOT a permissible method for protecting a conduit that runs through a concrete slab? A) Rigid metal conduit (RMC) B) PVC conduit with listed concrete-encased fittings C) NM cable in conduit D) EMT conduit with listed conduit bodies Answer: C Explanation: NM (Romex) is not allowed in conduit that is encased in concrete; only raceways rated for that environment may be used. Question 14. The NEC defines “ground-fault current” as a current flowing from: A) Phase to neutral B) Phase to ground C) Neutral to ground D) Phase to phase Answer: B Explanation: Ground-fault current is the unintended flow of current from a phase (hot) conductor to ground. Question 15. Which of the following devices provides protection against both ground-fault and arc-fault conditions? A) GFCI B) AFCI C) Dual-function GFCI/AFCI D) Surge protector Answer: C Explanation: Dual-function devices combine GFCI and AFCI protection in a single breaker or receptacle.
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Question 19. A 14-AWG copper conductor is used for a 15 A branch circuit. What is the minimum insulation temperature rating required for this circuit in a dwelling? A) 60 °C B) 75 °C C) 90 °C D) 105 °C Answer: B Explanation: NEC Table 310.15(B)(16) indicates 75 °C insulation is required for 15 A circuits in residential applications. Question 20. Which of the following is the correct method to identify a grounded (neutral) conductor in a 4-wire cable? A) White or gray insulation B) Black insulation C) Green insulation D) Bare copper only Answer: A Explanation: NEC requires neutral conductors to be white or gray. Question 21. In a single-line diagram, a circle with the letter “M” inside denotes which piece of equipment? A) Motor B) Meter C) Manual disconnect D) Main breaker Answer: A Explanation: The “M” inside a circle is the standard symbol for a motor. Question 22. Which NEC rule determines the maximum number of conductors allowed in a 1-in. EMT conduit?
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A) Table 1, Chapter 9 B) Table 4, Chapter 9 C) Table 5, Chapter 9 D) Table 6, Chapter 9 Answer: B Explanation: Table 4 of Chapter 9 provides conduit fill limits for EMT and other raceways. Question 23. A 250-V, 15-A receptacle is to be installed in a bathroom. Which NEC requirement applies? A) Must be GFCI protected B) Must be AFCI protected C) Must be on a dedicated 20-A circuit D) Must be on a 30-A circuit Answer: A Explanation: All bathroom receptacles require GFCI protection per Article 210.8(A) (1). Question 24. For a 3-phase, 4-wire delta-wye transformer, what is the phase voltage on the secondary side? A) Same as primary line voltage B) Same as primary phase voltage C) √3 × primary phase voltage D) Primary line voltage ÷ √ Answer: D Explanation: In a delta-wye, the secondary phase voltage equals the primary line voltage divided by √3. Question 25. Which of the following testing devices is best suited for detecting high-impedance ground faults?
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Question 28. Which NEC article addresses the installation of fire alarm circuits? A) Article 500 B) Article 760 C) Article 770 D) Article 800 Answer: B Explanation: Article 760 covers fire alarm systems, including wiring methods and power supplies. Question 29. A 120/240-V single-phase service requires a neutral conductor sized at 4 AWG copper. Which factor justifies this size? A) Voltage drop B) Ground-fault protection C) NEC Table 310.15(B)(16) ampacity for 60 °C D) 125 % of calculated load Answer: D Explanation: The neutral must be sized to carry 125 % of the calculated continuous load per NEC load-calculation rules. Question 30. Which of the following statements about AFCI protection is true? A) AFCIs protect only against ground-fault currents. B) AFCIs must be installed on all 15-A and 20-A branch circuits in dwelling unit bedrooms. C) AFCIs are not required in commercial occupancies. D) AFCIs can replace all GFCI devices. Answer: B Explanation: NEC 210.12(A) requires AFCI protection on all 15-A and 20-A branch circuits supplying outlets in bedrooms of dwelling units.
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Question 31. When reading an equipment schedule, the abbreviation “SW- 3 ” most likely indicates: A) Switch, 3-pole B) Switch, 3 A rating C) Switched receptacle, 3 ft spacing D) Switch, type 3 (momentary) Answer: A Explanation: “SW- 3 ” commonly denotes a three-pole switch. Question 32. Which NEC article governs the installation of low-voltage (<50 V) communication circuits? A) Article 300 B) Article 725 C) Article 800 D) Article 820 Answer: C Explanation: Article 800 covers communications circuits, including telephone, data, and coaxial cables. Question 33. For a feeder supplying a 100-A service, what is the minimum size copper conductor (THHN) required, assuming 75 °C insulation? A) #4 AWG B) #3 AWG C) #2 AWG D) #1 AWG Answer: C Explanation: Table 310.15(B)(16) shows #2 AWG copper THHN rated for 115 A at 75 °C, which satisfies a 100-A feeder.
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Question 37. In a three-phase, four-wire wye system, the neutral is considered a: A) Grounded conductor B) Ungrounded conductor C) Grounding conductor D) Separate system conductor Answer: A Explanation: The neutral in a wye system is the grounded (i.e., neutral) conductor. Question 38. Which NEC article addresses the installation of receptacles in outdoor locations? A) Article 210.52(G) B) Article 210.8(G) C) Article 210.70(G) D) Article 210.60(G) Answer: A Explanation: Article 210.52(G) specifies the requirement for outdoor receptacle placement. Question 39. A 30-kVA, 240-V three-phase transformer has a primary current of: A) 72 A B) 75 A C) 87 A D) 100 A Answer: A Explanation: Primary current = kVA × 1000 / (√3 × V) = 30,000 / (1.732 × 240) ≈ 72 A. Question 40. Which of the following devices must be listed for use in a damp or wet location?
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A) Standard plastic outlet B) GFCI receptacle with “wet-location” marking C) Standard toggle switch D) Non-metallic conduit Answer: B Explanation: GFCI receptacles intended for damp or wet locations must be listed for that use. Question 41. When performing a voltage drop calculation for a 150-ft run of 12 - AWG copper carrying 20 A at 120 V, the approximate voltage drop is: A) 1.5 V B) 2.5 V C) 3.5 V D) 4.5 V Answer: B Explanation: Using Vdrop = 2 × K × I × L / CM, where K≈12.9 for copper, CM=6530, L=150 ft, I=20 A → Vdrop ≈ 2.5 V. Question 42. Which NEC article defines the rules for installing wiring in raceways that are exposed to sunlight? A) Article 300. B) Article 310. C) Article 334. D) Article 358. Answer: D Explanation: Article 358 covers EMT, including requirements for sunlight exposure. Question 43. The “flash protection boundary” for an arc-flash incident energy of 12 cal/cm² is: A) 12 in.
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B) Article 590. C) Article 590. D) Article 590. Answer: A Explanation: Article 590 addresses the installation of electric signs and outline lighting. Question 47. The NEC permits the use of a single-pole breaker to protect a multi-wire branch circuit (MWBC) only if: A) The breaker has a common trip mechanism. B) The breakers are on adjacent phases. C) The circuit is 120 V only. D) The neutral is larger than the hots. Answer: A Explanation: A common-trip (or handle-tied) breaker ensures simultaneous disconnect of both ungrounded conductors. Question 48. When installing a conduit system in a hazardous (Class II) area, which of the following is required? A) Non-metallic conduit only B) Rigid metal conduit with a grounding conductor C) Flexible metal conduit with a listed flame-retardant coating D) No conduit is allowed; cable must be used. Answer: C Explanation: Class II hazardous locations allow FMC with a listed flame-retardant coating. Question 49. Which of the following is the correct NEC citation for the requirement that “all conductors must be enclosed in a raceway or cable assembly when passing through a fire-rated wall”? A) 300.
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B) 300.
C) 300.
D) 300.
Answer: B Explanation: NEC 300.22 requires conductors to be in a raceway or cable assembly when penetrating fire-rated assemblies. Question 50. A 240-V, 30-A dryer is installed in a garage. Which NEC article requires that a GFCI be provided for this receptacle? A) 210.8(A)(2) B) 210.8(A)(7) C) 210.8(A)(9) D) 210.8(A)(1) Answer: B Explanation: Article 210.8(A)(2) covers garages; however, for a dryer receptacle, the requirement is under 210.8(A)(7) for “garages and accessory buildings”. The correct answer is B. Question 51. In a three-phase, 4-wire wye system, the neutral conductor carries: A) Only unbalanced load current B) The sum of all phase currents C) No current under any condition D) The line-to-line voltage divided by √ 3 Answer: A Explanation: The neutral carries only the vector sum of unbalanced phase currents. Question 52. Which NEC article addresses the installation of conduit in concrete? A) 300. B) 300.
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C) Article 210.8(B) D) Article 300. Answer: A Explanation: Article 517 covers health-care facilities, including receptacle placement. Question 56. A 120/208-V, three-phase system supplies a lighting load of 10 kW. What is the approximate current per phase, assuming a balanced load and a power factor of 0.9? A) 27 A B) 33 A C) 38 A D) 45 A Answer: B Explanation: Apparent power S = 10 kW / 0.9 = 11.11 kVA. I = S / (√3 × V) = 11, / (1.732 × 208) ≈ 30.9 A ≈ 33 A. Question 57. Which of the following is the correct NEC reference for the requirement that “ground-fault circuit-interrupters must be installed in all 15- and 20 - A 125-V receptacles in unfinished basements”? A) 210.8(A)(5) B) 210.8(A)(6) C) 210.8(A)(7) D) 210.8(A)(8) Answer: A Explanation: Article 210.8(A)(5) requires GFCI protection in unfinished basements. Question 58. For a 250-V, 30-A circuit feeding an air-conditioning unit, which type of overcurrent device is typically used? A) Standard thermal-magnetic breaker B) Time-delay (inverse-time) breaker
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C) Instantaneous-trip breaker D) Fuse with a 30-A rating Answer: B Explanation: Motors and AC units often require a time-delay (inverse-time) breaker to accommodate inrush currents. Question 59. Which of the following best describes a “dedicated branch circuit”? A) A circuit that supplies only one type of equipment or appliance. B) A circuit that supplies multiple receptacles throughout a room. C) A circuit that shares a neutral with another circuit. D) A circuit that is protected by a GFCI. Answer: A Explanation: A dedicated branch circuit supplies a single appliance or equipment, per NEC definitions. Question 60. According to NEC, what is the minimum height for a receptacle installed in a garage that is not above a workbench? A) 12 in. above floor B) 18 in. above floor C) 24 in. above floor D) 30 in. above floor Answer: B Explanation: NEC 210.52(G) requires garage receptacles to be installed not less than 18 in. above the floor. Question 61. Which NEC article governs the installation of wiring for swimming pools? A) Article 680 B) Article 690 C) Article 690.
