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Electrician Ultimate Exam
Question 1. Which NEC article defines the term “qualified person” for industrial electrical work? A) Article 100 B) Article 110 C) Article 210 D) Article 250 Answer: A Explanation: Article 100 provides definitions for terms used throughout the NEC, including “qualified person.” Question 2. According to Article 110, what is the minimum height for a working space above a switchboard that is 8 ft high? A) 3 ft B) 6 ft C) 8 ft D) 10 ft Answer: B Explanation: Article 110.26 requires a minimum headroom of 6 ft for equipment taller than 6 ft. Question 3. Ohm’s Law states that voltage equals current multiplied by resistance. If a motor draws 25 A and its resistance is 0.4 Ω, what is the voltage? A) 10 V B) 15 V C) 6 V D) 100 V Answer: D Explanation: V = I × R = 25 A × 0.4 Ω = 10 V (incorrect). Actually 25 A × 0.4 Ω = 10 V, but answer choices are wrong. Correct answer is 10 V, which corresponds to choice A. Therefore the correct answer is A.
Electrician Ultimate Exam
Question 4. In a P&ID, the symbol of a double line with a “T” indicates which component? A) Transformer B) Temperature sensor C) Throttle valve D) Terminal block Answer: A Explanation: The double line with a “T” is the standard P&ID symbol for a transformer. Question 5. Which waveform best represents a typical three-phase, 120-degree phase-shifted system? A) Single sine wave B) Three sine waves offset 120° C) Square wave D) Pulsating DC Answer: B Explanation: A three-phase system consists of three sinusoidal voltages displaced by 120° from each other. Question 6. When sizing a service-entrance conductor for a 400 A load, which factor must be considered first? A) Voltage drop B) Conductor ampacity C) Conduit fill D) Grounding electrode size Answer: B Explanation: The conductor must have an ampacity equal to or greater than the load current before other considerations.
Electrician Ultimate Exam
Question 10. The grounding electrode conductor for a 200-kVA transformer must be sized according to which table? A) Table 250. B) Table 310.15(B)(16) C) Table 220. D) Table 310. Answer: A Explanation: Table 250.66 provides the minimum size of grounding electrode conductors based on the size of the service or feeder. Question 11. When calculating feeder load for a 5-hp motor operating at 460 V, 3 - phase, which demand factor is appropriate per NEC Table 220.55? A) 100% B) 80% C) 65% D) 50% Answer: B Explanation: Table 220.55 permits a 80% demand factor for motors 1 hp to 30 hp. Question 12. The overcurrent protective device (OCPD) for a feeder must not exceed which percentage of the conductor’s ampacity? A) 80% B) 100% C) 125% D) 150% Answer: B Explanation: NEC 240.4(G) states the OCPD shall not exceed 100% of the conductor’s ampacity unless otherwise permitted. Question 13. A 20-A branch circuit supplying a receptacle in an industrial workshop must use which minimum conductor size?
Electrician Ultimate Exam
A) 12 AWG copper B) 14 AWG copper C) 10 AWG copper D) 8 AWG copper Answer: A Explanation: Per Table 310.16, 12 AWG copper is rated for 20 A in most conditions. Question 14. Which color is used to identify a grounded (neutral) conductor in a 208/120-V system? A) Black B) Red C) White D) Green Answer: C Explanation: NEC 200.6 designates white (or gray) for grounded conductors. Question 15. In an industrial panel, the ungrounded conductors must be identified by: A) White or gray B) Green or bare C) Any color except white, gray, green, or bare D) Red only Answer: C Explanation: NEC 200.6(A) allows any color other than those reserved for grounded or grounding conductors. Question 16. The maximum conduit fill for a single 3/4-in. EMT conduit containing three #4 AWG THHN conductors is: A) 40% B) 53%
Electrician Ultimate Exam
D) None; bonding is optional Answer: C Explanation: NEC 250.32 requires bonding to all conductive parts that could become energized. Question 20. Which type of cable is permitted for use in a suspended industrial rack system without additional support? A) Type MC B) Type TC C) Type MI D) Type NM-B Answer: B Explanation: Type TC (tray cable) is designed for use in cable trays and can be run without additional support. Question 21. The maximum spacing for supporting Type MC cable in an industrial rack is: A) 4 ft B) 6 ft C) 8 ft D) 10 ft Answer: C Explanation: NEC 330.30 allows support every 8 ft for Type MC. Question 22. For a motor rated 30 hp, 460 V, 3-phase, what is the minimum size of the motor overload protection device? A) 125 % of full-load amps B) 150 % of full-load amps C) 200 % of full-load amps D) 250 % of full-load amps Answer: B
Electrician Ultimate Exam
Explanation: NEC 430.32 requires motor overloads to be set at 125- 150 % of the motor’s full-load current; 150 % is the maximum for inverse-time devices. Question 23. The disconnecting means for a motor must be located within how many feet of the motor? A) 25 ft B) 30 ft C) 50 ft D) No distance requirement Answer: D Explanation: NEC 430.102 does not impose a specific distance; the disconnect must be readily accessible. Question 24. In an industrial control panel, Class 1 circuits are required to be protected by which type of OCPD? A) Fuses only B) Circuit breakers only C) Either fuses or circuit breakers rated for the circuit’s voltage and current D) No protection needed Answer: C Explanation: Class 1 circuits can be protected by either fuses or breakers as long as they meet the rating requirements. Question 25. Which article governs the installation of industrial control panels? A) Article 408 B) Article 409 C) Article 410 D) Article 411 Answer: B Explanation: Article 409 covers industrial control panels, including construction and wiring requirements.
Electrician Ultimate Exam
A) Class I, Division 1 B) Class II, Division 2 C) Class III, Division 1 D) All of the above Answer: C Explanation: Intrinsically safe systems are designed for Class III locations where dust or fibers are present. Question 30. The minimum separation between a welding circuit and a power circuit in a control panel is: A) 1 in B) 2 in C) 4 in D) No separation required Answer: C Explanation: NEC 630.31 requires a minimum 4-in separation between welding and power circuits. Question 31. An industrial transformer’s primary is connected to a 480 V source. The secondary supplies a 240 V load. What is the transformer’s turns ratio? A) 1: B) 2: C) 1: D) 4: Answer: B Explanation: Turns ratio = Primary Voltage / Secondary Voltage = 480 V / 240 V = 2:1. Question 32. The grounding conductor for a transformer must be sized based on which of the following? A) Primary voltage only
Electrician Ultimate Exam
B) Secondary voltage only C) The larger of the primary or secondary full-load current D) The transformer’s kVA rating Answer: C Explanation: NEC 450.20 requires the grounding conductor to be sized for the larger of the two currents. Question 33. A lighting fixture rated for 120 V, 500 W, is installed in a 208 V system. What is the minimum voltage rating the fixture must have? A) 120 V B) 208 V C) 277 V D) 600 V Answer: B Explanation: Fixtures must be rated for at least the system voltage; thus a 208 V rating is required. Question 34. For a 10-kW motor, what is the approximate full-load current at 460 V, 3-phase? (Use I = P / (√ 3 × V × PF), assume PF = 0.9) A) 12 A B) 15 A C) 20 A D) 25 A Answer: B Explanation: I = 10,000 W / (1.732 × 460 V × 0.9) ≈ 13.9 A, rounded to 15 A. Question 35. Which NEC article governs the installation of photovoltaic (PV) systems? A) Article 690 B) Article 705 C) Article 710
Electrician Ultimate Exam
Explanation: NEC recommends a maximum of 3% voltage drop for feeders supplying motor loads. Question 39. Ambient temperature correction for conductors at 40 °C (104 °F) results in what factor for copper conductors? A) 0. B) 0. C) 1. D) 1. Answer: B Explanation: Table 310.15(B)(2)(a) provides a correction factor of 0.94 for 40 °C. Question 40. A conduit contains six #6 AWG THHN conductors. What is the minimum conduit size required? A) 1/2 in. EMT B) 3/4 in. EMT C) 1 in. EMT D) 1-1/4 in. EMT Answer: C Explanation: Table 9 shows that six #6 AWG THHN require at least 1-in. EMT for 40% fill. Question 41. The grounding electrode conductor for a 150-kVA service must be at least which size? A) #8 AWG copper B) #6 AWG copper C) #4 AWG copper D) #2 AWG copper Answer: B Explanation: Table 250.66 specifies #6 AWG copper for a 150-kVA service.
Electrician Ultimate Exam
Question 42. Which article governs the installation of industrial motor controllers? A) Article 430 B) Article 440 C) Article 450 D) Article 460 Answer: A Explanation: Article 430 contains requirements for motors, motor circuits, and controllers. Question 43. A motor starter must be protected by an overload set to 115 % of the motor’s full-load current. This setting is: A) Below the minimum allowed B) Within the allowable range C) Above the maximum allowed D) Not permitted by NEC Answer: B Explanation: NEC 430.32 permits overload settings between 115 % and 125 % of full-load current. Question 44. For a 3-phase, 480 V feeder supplying a 100-kW load, what is the approximate feeder current? (PF = 0.9) A) 115 A B) 130 A C) 150 A D) 175 A Answer: B Explanation: I = 100,000 W / (1.732 × 480 V × 0.9) ≈ 133 A, rounded to 130 A. Question 45. Which of the following is a required marking on a conduit that contains a grounded (neutral) conductor?
Electrician Ultimate Exam
C) 50 A
D) 60 A
Answer: B Explanation: NEC 450.3 requires OCPD not to exceed 125% of full-load current: 36 A × 1.25 = 45 A. Question 49. Which NEC article addresses grounding and bonding of piping systems? A) Article 250 B) Article 300 C) Article 110 D) Article 210 Answer: A Explanation: Article 250 contains the requirements for grounding and bonding, including piping. Question 50. In a Class I, Division 2 hazardous location, which type of conduit is acceptable? A) Rigid Metal Conduit (RMC) with non-explosion-proof fittings B) Flexible Metal Conduit (FMC) with standard fittings C) EMT with explosion-proof fittings D) PVC conduit only Answer: C Explanation: EMT with explosion-proof fittings is permitted in Class I, Division 2 locations. Question 51. The minimum clearance between a service disconnect and a floor drain is: A) 6 in B) 12 in C) 18 in
Electrician Ultimate Exam
D) No specific clearance required Answer: B Explanation: NEC 110.26 requires a minimum 12-in clearance from the floor to the bottom of equipment. Question 52. Which of the following is NOT a permissible method for bonding a metal conduit system? A) Using a bonding jumper B) Relying on the grounding conductor within the cable C) Using the conduit itself as the grounding path D) Installing a grounding electrode conductor to the conduit Answer: B Explanation: The grounding conductor within a cable cannot be used to bond a conduit system; a separate bonding jumper or the conduit itself must be used. Question 53. The NEC requires that a disconnecting means for a motor must be capable of opening the full load current at what voltage? A) 120 V B) 208 V C) 240 V D) The motor’s rated voltage Answer: D Explanation: The disconnect must be rated for the motor’s operating voltage. Question 54. In an industrial building, the minimum height for a working space above a floor-mounted panelboard is: A) 3 ft B) 6 ft C) 8 ft D) 10 ft Answer: B
Electrician Ultimate Exam
Question 58. A motor’s service factor (SF) of 1.15 indicates: A) The motor can operate 15% above its rated horsepower continuously. B) The motor’s overload protection must be set at 115% of full-load current. C) The motor can handle 15% higher current during short-term overloads. D) The motor’s efficiency is 115%. Answer: C Explanation: Service factor allows the motor to handle up to 15% higher current for short periods. Question 59. Which table is used to determine the ampacity of conductors in conduit when the ambient temperature is 40 °C? A) Table 310.15(B)(2)(a) B) Table 310. C) Table 220. D) Table 250. Answer: A Explanation: Table 310.15(B)(2)(a) provides temperature correction factors for conductors. Question 60. The minimum size of a grounding electrode conductor for a 600-V, 400 A service is: A) #8 AWG copper B) #6 AWG copper C) #4 AWG copper D) #2 AWG copper Answer: C Explanation: Table 250.66 indicates #4 AWG copper for a 400 A service at 600 V. Question 61. In a hazardous location, intrinsically safe equipment must be approved by which organization? A) UL (Underwriters Laboratories)
Electrician Ultimate Exam
B) IEEE (Institute of Electrical and Electronics Engineers) C) NEC (National Electrical Code) itself D) ANSI (American National Standards Institute) Answer: A Explanation: UL provides certification for intrinsically safe equipment per NEC requirements. Question 62. The NEC permits the use of conduit as a grounding electrode if: A) The conduit is made of steel only B) The conduit is bonded at each end with a grounding clamp C) The conduit is installed in a wet location only D) The conduit is PVC Answer: B Explanation: The conduit must be bonded at each end to serve as a grounding electrode. Question 63. Which article governs the installation of industrial welders? A) Article 630 B) Article 640 C) Article 650 D) Article 660 Answer: A Explanation: Article 630 covers welding, cutting, and brazing equipment. Question 64. A 120 V, 15 A receptacle in an industrial shop must be protected by a circuit breaker with a rating not exceeding: A) 15 A B) 20 A C) 25 A D) 30 A
