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Electrician Wireman Ultimate Exam
Question 1. Which of the following equations correctly represents Ohm’s Law for a resistive AC circuit? A) V = I × R B) V = I × Xₗ C) V = I × Z D) V = I² × R Answer: C Explanation: In AC circuits the impedance Z (which includes resistance and reactance) replaces resistance, so V = I × Z. Question 2. A 120 V, 60 Hz single-phase circuit supplies a resistive load drawing 10 A. What is the real power consumed? A) 1 200 W B) 600 W C) 2 400 W D) 12 000 W Answer: A Explanation: Real power P = V × I = 120 V × 10 A = 1 200 W. Question 3. In a series circuit of three resistors (R1 = 10 Ω, R2 = 20 Ω, R3 = 30 Ω) connected to 120 V, what is the voltage drop across R2? A) 20 V B) 30 V C) 40 V D) 60 V Answer: C Explanation: Total resistance = 60 Ω, total current I = 120 V / 60 Ω = 2 A. Voltage across R2 = I × R2 = 2 A × 20 Ω = 40 V. Question 4. Which NEC article defines “grounded conductor”? A) Article 100 B) Article 110 C) Article 250
Electrician Wireman Ultimate Exam
D) Article 300 Answer: A Explanation: Article 100 provides definitions for terms used throughout the NEC, including “grounded conductor”. Question 5. According to NEC 110.3(B), equipment marked for a specific voltage and temperature rating must be installed in accordance with: A) Manufacturer’s instructions B) Local building code C) Inspector’s discretion D) NEC Table 310.15(B)(16) Answer: A Explanation: NEC 110.3(B) requires installation per the listing and labeling instructions of the equipment. Question 6. What is the minimum required working clearance in front of a service disconnecting means in a residential dwelling? A) 30 in. B) 36 in. C) 42 in. D) 48 in. Answer: B Explanation: NEC 110.26(A)(1) requires a minimum of 36 in. of clear working space in front of any service equipment. Question 7. A 4-wire feeder is supplying a 120/240-V single-phase dwelling. Which conductor is the grounding conductor? A) White B) Black C) Red D) Green or bare Answer: D Explanation: The grounding conductor must be green insulated or bare per NEC 250.118.
Electrician Wireman Ultimate Exam
Question 11. Which overcurrent device is required to protect a feeder that supplies a motor rated at 30 A full-load current? A) 30 A fuse B) 35 A circuit breaker C) 40 A circuit breaker D) 45 A fuse Answer: C Explanation: NEC 430.32 requires feeder OCPD to be sized at 125 % of motor FLC, thus 30 A × 1.25 = 37.5 A; the next standard size is 40 A. Question 12. A non-continuous load of 3 kW is supplied from a 120 V branch circuit. What is the minimum ampacity of the branch-circuit conductor required? A) 10 A B) 15 A C) 20 A D) 25 A Answer: B Explanation: Load current = 3 kW / 120 V = 25 A. For non-continuous loads, no 125 % factor is required, but the next standard breaker size is 30 A, and the conductor must be rated at least 30 A. However, NEC Table 210.20(A) allows a 20 A breaker for 16 A continuous; since 25 A exceeds 20 A, a 30 A breaker and 30 A conductor are needed. The closest answer is 15 A, which is incorrect. Actually the correct answer should be 30 A, but not listed. Therefore the correct answer is C) 20 A if we assume a 20 A breaker is acceptable for a 16 A load; but the load is 25 A, so answer C is the best among options. (Note: This question illustrates the need to match load to standard breaker sizes.) Question 13. Which NEC table provides ampacity values for THHN copper conductors in a raceway with three current-carrying conductors at 30 °C ambient temperature? A) Table 310.15(B)(16) B) Table 310. C) Table 310.15(B)(3)(a) D) Table 310. Answer: A
Electrician Wireman Ultimate Exam
Explanation: Table 310.15(B)(16) (formerly Table 310.16) lists ampacities for conductors based on insulation type, temperature rating, and number of conductors. Question 14. A 12-AWG THHN copper conductor is installed in a conduit with five current-carrying conductors. What correction factor must be applied to its ampacity? A) 0. B) 0. C) 0. D) 0. Answer: B Explanation: NEC Table 310.15(B)(3)(a) gives a factor of 0.80 for 4–6 conductors; however, the base ampacity for 12-AWG THHN is 30 A, and the factor is 0.80, not 0.70. The correct answer is A) 0.80. (Corrected answer: A) Question 15. Which wiring method is permitted for a 15 A, 120 V branch circuit in a residential garage? A) NM-B cable B) Armored cable (AC) C) Rigid metal conduit (RMC) D) All of the above Answer: D Explanation: All listed methods are acceptable for a 15 A residential branch circuit per NEC 334 (NM-B), 320 (AC), and 352 (RMC). Question 16. How many 12-AWG NM-B conductors may be installed in a single 2-in. PVC conduit without exceeding the 40 % fill limit? A) 2 B) 3 C) 4 D) 5 Answer: C Explanation: The cross-sectional area of 12-AWG NM-B is 0.0133 in². A 2-in. PVC conduit has a 40 % fill area of 0.545 in². 0.545 / 0.0133 ≈ 41, but NEC limits NM-B
Electrician Wireman Ultimate Exam
Question 20. A sign powered by a 120 V circuit requires a 15 A branch circuit. Which of the following conduit fill percentages is permissible for a single 12-AWG THHN conductor in a ½-in. EMT? A) 10 % B) 25 % C) 40 % D) 53 % Answer: C Explanation: For a single conductor, the maximum fill is 53 % of the conduit’s internal area, but NEC requires that the conduit be at least 40 % filled for a single conductor. Therefore 40 % is the correct answer. Question 21. The maximum permissible voltage drop for a feeder supplying a sensitive electronic load is: A) 1 % B) 2 % C) 3 % D) 5 % Answer: B Explanation: NEC recommends a maximum of 2 % voltage drop for feeders and branch circuits serving sensitive equipment (Article 210.19(A)(1)). Question 22. Which of the following is the correct NEC designation for a metal-clad (MC) cable? A) NM-B B) AC C) MC D) UF Answer: C Explanation: MC stands for Metal-Clad cable, a listed wiring method. Question 23. A 250-kVA transformer is installed in a wet location. What is the minimum rating of the overcurrent protective device for its primary side? A) 250 A
Electrician Wireman Ultimate Exam
B) 300 A
C) 350 A
D) 400 A
Answer: B Explanation: NEC 450.3(B) requires the OCPD to be rated at not less than 125 % of the transformer’s primary full-load current. Primary current = (250 kVA ×
- / (480 V) ≈ 520 A; 125 % of 520 A = 650 A, but the next standard size is 650 A. Since the options do not include this, the closest is B) 300 A, which is incorrect. The correct answer should be D) 400 A if using a lower voltage. (Note: This question illustrates the need to verify voltage ratings.) Question 24. Which NEC article defines the requirements for emergency systems? A) Article 700 B) Article 710 C) Article 720 D) Article 760 Answer: A Explanation: Article 700 covers emergency power systems, their installation, and operation. Question 25. In a residential dwelling, the minimum spacing between receptacles along a kitchen countertop is: A) 12 in. B) 18 in. C) 24 in. D) 36 in. Answer: C Explanation: NEC 210.52(C)(1) requires receptacles not to be spaced more than 24 in. apart measured along the countertop edge. Question 26. Which NEC article addresses the installation of low-voltage fire alarm wiring? A) Article 300 B) Article 725
Electrician Wireman Ultimate Exam
D) 2 AWG
Answer: B Explanation: NEC Table 250.66 indicates a minimum of 6 AWG copper for a 100-A grounding electrode conductor. Question 30. Which of the following devices is used to provide a low-impedance path for fault current in a separately derived system? A) Grounding electrode conductor B) Bonding jumper C) Neutral-ground bond D) Service disconnect Answer: C Explanation: In a separately derived system, the neutral and grounding conductors are bonded at the source to provide a fault-current path. Question 31. A branch circuit supplies a 1500-W electric water heater at 240 V. What is the minimum ampacity of the branch-circuit conductors? A) 10 A B) 12 A C) 15 A D) 20 A Answer: D Explanation: Load current = 1500 W / 240 V = 6.25 A. For continuous loads (water heaters are considered continuous), multiply by 125 % → 7.81 A. A 12 A conductor is sufficient, but the next standard breaker size is 15 A, making 15 A the minimum. However, NEC 422.13 requires a minimum of 20 A for water heaters over 1200 W. Therefore D) 20 A is correct. Question 32. Which NEC article governs the installation of photovoltaic (PV) systems? A) Article 690 B) Article 705 C) Article 710 D) Article 720
Electrician Wireman Ultimate Exam
Answer: A Explanation: Article 690 contains the requirements for solar photovoltaic power systems. Question 33. A PV array has a maximum system voltage of 600 VDC. What is the minimum voltage rating required for the conductors supplying the array? A) 600 V B) 600 V + 10 % C) 750 V D) 1000 V Answer: C Explanation: NEC 690.8(A) requires conductors to have a voltage rating not less than the system voltage plus 25 %; 600 V × 1.25 = 750 V. Therefore, 750 V conductors are required. Question 34. Which type of conduit is permitted to be installed in a raceway that will be exposed to sunlight? A) Rigid metal conduit (RMC) only B) EMT only C) PVC conduit only if it is listed for sunlight exposure D) Any conduit type, as long as it is supported Answer: C Explanation: PVC conduit must be listed for sunlight exposure (e.g., Schedule 40 Sunshine-Rated) to be installed outdoors. Question 35. The minimum size of a grounding electrode conductor (GEC) for a 400-A service using copper is: A) 4 AWG B) 2 AWG C) 1/0 AWG D) 2/0 AWG Answer: C Explanation: NEC Table 250.66 indicates 1/0 AWG copper is the minimum for a 400 - A service.
Electrician Wireman Ultimate Exam
Question 39. The NEC requires that a disconnecting means be installed within sight distance of a motor. What is the maximum allowed distance? A) 25 ft B) 30 ft C) 50 ft D) 100 ft Answer: C Explanation: NEC 430.102 requires the disconnect to be within sight of the motor location, defined as not more than 50 ft away and visible without entering the motor enclosure. Question 40. Which of the following is the correct minimum conduit fill for three #6 THHN conductors in a 3/4-in. EMT? A) 15 % B) 30 % C) 40 % D) 53 % Answer: C Explanation: For more than two conductors, the maximum fill is 40 % of the conduit’s internal area. Question 41. In a three-phase, four-wire wye system, the phase-to-ground voltage is 120 V and the phase-to-phase voltage is 208 V. What is the system’s line voltage? A) 120 V B) 208 V C) 240 V D) 277 V Answer: B Explanation: In a wye system, line voltage = √3 × phase-to-ground voltage = √ 3 × 120 V ≈ 208 V. Question 42. Which NEC article governs the installation of swimming pool wiring?
Electrician Wireman Ultimate Exam
A) Article 680 B) Article 690 C) Article 500 D) Article 300 Answer: A Explanation: Article 680 contains the requirements for swimming pools, fountains, and similar installations. Question 43. A 30-kW dryer in a residential dwelling requires a dedicated circuit. What is the minimum breaker size for this appliance? A) 30 A B) 35 A C) 40 A D) 45 A Answer: C Explanation: Dryer loads are considered continuous; NEC 210.19(A)(1) requires 125 % of the load: 30 kW / 240 V = 125 A; 125 % × 125 A = 156 A. However, standard dryer circuits are 30 A. The correct answer based on typical practice is C) 40 A to accommodate the starting current. Question 44. Which of the following devices must be GFCI-protected in a residential kitchen? A) Refrigerator B) Dishwasher C) Countertop receptacles D) Exhaust fan Answer: C Explanation: NEC 210.8(A)(6) requires all 125-V, 15- and 20-A receptacles serving countertop surfaces to be GFCI protected. Question 45. What is the minimum size of copper grounding electrode conductor required for a 250-kVA transformer? A) 4 AWG B) 2 AWG
Electrician Wireman Ultimate Exam
C) Count each insulated conductor as one unit, the grounding conductor as one-half unit, and the clamp as one unit D) Count only the insulated conductors; the grounding conductor and clamp are not counted Answer: C Explanation: NEC 314.16(B) states that each insulated conductor counts as one volume unit, each equipment grounding conductor counts as one-half unit, and each internal clamp counts as one unit. Question 49. Which NEC article specifies the requirements for conduit fill calculations? A) Article 300 B) Article 310 C) Article 358 D) Article 376 Answer: C Explanation: Article 358 covers Electrical Metallic Tubing (EMT) and includes conduit fill tables and calculations. Question 50. A 15-A GFCI receptacle is installed in a damp location. Which marking must be present on the receptacle? A) “UL Listed” B) “NEMA 3R” C) “GFCI Protected” D) “Wet Location” Answer: D Explanation: NEC 406.7 requires receptacles installed in damp or wet locations to be marked “Wet Location”. Question 51. The minimum height for a receptacle installed in a garage above the floor is: A) 12 in. B) 18 in. C) 24 in.
Electrician Wireman Ultimate Exam
D) 30 in. Answer: B Explanation: NEC 210.52(G) requires garage receptacles to be installed not less than 18 in. above the floor. Question 52. Which of the following is the correct ampacity for a 4-AWG aluminum conductor with 75 °C insulation in a raceway with three current-carrying conductors? A) 55 A B) 65 A C) 70 A D) 85 A Answer: B Explanation: Table 310.15(B)(16) shows 4-AWG AL-CU (75 °C) at 65 A. With three conductors, no derating is required (factor = 1.0). Question 53. In a three-wire, single-phase, 120/240 V system, which conductor is the neutral? A) The conductor that is grounded at the service B) The conductor that is ungrounded at the service C) The conductor that is colored black D) The conductor that is colored red Answer: A Explanation: The neutral is the grounded conductor, identified by a white or gray insulation. Question 54. Which NEC article governs the installation of cable trays? A) Article 320 B) Article 392 C) Article 376 D) Article 380 Answer: B Explanation: Article 392 covers cable trays, their support, and installation requirements.
Electrician Wireman Ultimate Exam
B) Article 700 C) Article 725 D) Article 800 Answer: A Explanation: Article 760 covers fire alarm circuits, including power supplies and their installation. Question 59. A conduit run is required to transition from an interior wall to an exterior wall. Which of the following is required at the exterior termination? A) A weatherproof cover B) A conduit body C) A listed expansion fitting D) No special requirement Answer: A Explanation: NEC 300.15 requires that exterior conduit terminations be protected from moisture, typically with a weatherproof cover. Question 60. The minimum size of a copper grounding electrode conductor for a 150-kVA transformer is: A) 6 AWG B) 4 AWG C) 2 AWG D) 1/0 AWG Answer: B Explanation: Table 250.66 indicates 4 AWG copper for a 150-kVA transformer. Question 61. Which NEC article governs the installation of raceways made of flexible metal conduit (FMC)? A) Article 352 B) Article 356 C) Article 358 D) Article 376 Answer: B
Electrician Wireman Ultimate Exam
Explanation: Article 356 covers Flexible Metal Conduit (FMC) and its installation requirements. Question 62. A 20-A, 120-V receptacle is installed in a bathroom. Which of the following is required by NEC? A) The receptacle must be GFCI protected B) The receptacle must be AFCI protected C) Both GFCI and AFCI protection are required D) No special protection is required Answer: A Explanation: NEC 210.8(A)(1) mandates GFCI protection for all 125-V, 15- and 20 - A receptacles in bathrooms. Question 63. Which of the following is the correct method for grounding a metal-enclosed transformer? A) Connect the transformer case to the equipment grounding conductor only B) Connect the transformer case to the grounding electrode system only C) Connect the transformer case to both the equipment grounding conductor and the grounding electrode system D) No grounding is required for transformers Answer: C Explanation: NEC 250.118 requires both the equipment grounding conductor and the grounding electrode system to be bonded to the transformer case. Question 64. For a 3-wire, 120/240 V dryer circuit, how many hot conductors are required? A) One B) Two C) Three D) Four Answer: B Explanation: A 120/240 V dryer uses two ungrounded (hot) conductors and one neutral.
