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Contractor Master Electrician AL
Ultimate Exam
Question 1. Which formula correctly represents Ohm’s Law for a resistive circuit? A) P = V × I B) V = I × R C) I = V / P D) R = P / I Answer: B Explanation: Ohm’s Law states that voltage (V) equals current (I) multiplied by resistance (R). Question 2. In a three-phase, four-wire wye system, what is the relationship between line voltage (V_L) and phase voltage (V_P)? A) V_L = V_P B) V_L = √2 × V_P C) V_L = √3 × V_P D) V_L = 2 × V_P Answer: C Explanation: In a wye system, line voltage equals √3 times the phase voltage. Question 3. Which NEC article defines the purpose and scope of the Code? A) Article 90 B) Article 100 C) Article 110 D) Article 210 Answer: A Explanation: Article 90 provides the purpose, scope, and authority of the NEC. Question 4. According to NEC terminology, a “feeder” is best described as:
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A) A circuit that supplies power directly to loads B) A conductor that originates at the service equipment and supplies one or more branch circuits C) The main disconnecting means for a building D) A wiring method used only outdoors Answer: B Explanation: A feeder carries power from the service equipment to distribution panels or sub-panels. Question 5. Which symbol on a single-line diagram represents a transformer? A) Two parallel lines with a circle B) A rectangle with “T” inside C) Two concentric circles with a line through them D) A pair of overlapping circles Answer: C Explanation: The standard symbol for a transformer is two concentric circles with a line indicating the core. Question 6. For a continuous load, the NEC requires the branch-circuit overcurrent device to be sized at least what percentage of the load? A) 80% B) 100% C) 125% D) 150% Answer: C Explanation: Continuous loads must be protected at 125% of the calculated load. Question 7. Which of the following is a mandatory (shall) requirement in the NEC?
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A) Table 310.15(B)(16) B) Table 250. C) Table 220. D) Table 215.2(A)(1) Answer: B Explanation: Table 250.66 provides GEC sizing based on the size of the service-entrance conductors. Question 11. The NEC permits the use of flexible metal conduit (FMC) as an equipment grounding conductor under which condition? A) When the FMC is larger than 1 in. B) When the FMC is installed in a wet location. C) When the FMC is listed for grounding use. D) When the FMC is the only conduit present. Answer: C Explanation: FMC may serve as an equipment grounding conductor if it is listed for that purpose. Question 12. In a dwelling unit, which area requires a dedicated 20-A GFCI-protected branch circuit? A) Living room receptacles B) Kitchen countertop receptacles C) Bedroom ceiling fans D) Hallway lighting Answer: B Explanation: The NEC requires GFCI protection for countertop receptacles in kitchens.
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Ultimate Exam
Question 13. Which type of AFCI protection is required for a bedroom branch circuit in a new residential construction? A) Branch-circuit AFCI only B) Combination AFCI (branch-circuit and outlet) C) Outlet-type AFCI only D) No AFCI required Answer: B Explanation: The NEC mandates combination AFCI protection for bedroom circuits. Question 14. According to NEC Article 310.15(B)(3)(a), what is the derating factor for four current-carrying conductors in a single raceway? A) 80% B) 90% C) 70% D) 100% Answer: B Explanation: For 4-5 conductors, the ampacity must be multiplied by 80%; however, the first correction factor listed is 80% for 4-6 conductors. (Correction: The correct factor is 80%; answer B.) Question 15. Which conductor insulation type is permitted for use in wet or damp locations? A) THHN only B) XHHW- 2 C) NM-B D) UF-B Answer: B Explanation: XHHW-2 is rated for wet locations; NM-B is not.
Contractor Master Electrician AL
Ultimate Exam
Explanation: Article 340 covers MC cable requirements. Question 19. For a 120/240-V single-phase service, the neutral conductor must be sized at least what proportion of the ungrounded conductor? A) 25% B) 50% C) 75% D) Same size as the ungrounded conductor Answer: D Explanation: The neutral must be the same ampacity as the ungrounded conductors unless a load calculation permits otherwise. Question 20. The NEC requires a disconnecting means for a permanently installed appliance that is rated greater than 120 V, 50 A, or 3 kW. This disconnect must be located where? A) Inside the appliance enclosure B) Within sight of the appliance C) At the service panel only D) Anywhere in the building Answer: B Explanation: The disconnect must be readily accessible and within sight of the appliance. Question 21. A motor-operated air-compressor has a nameplate full-load current (FLC) of 22 A. What is the minimum size of the branch-circuit overcurrent device required? A) 20 A B) 25 A C) 30 A D) 35 A
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Answer: C Explanation: NEC 430.22 requires the OCPD to be 250% of the FLC for single-phase motors: 22 A × 2.5 = 55 A, but the next standard size is 60 A. (Correct answer: D – 60 A. Adjusted.) Question 22. Which statement about motor overload protection is correct? A) It must be set at 100 % of the motor’s FLC. B) It may be set between 115 % and 125 % of the motor’s rated current. C) It must be a thermal overload only. D) It is optional for motors over 30 HP. Answer: B Explanation: NEC 430.32 permits overloads set at 115- 125 % of the motor’s rated current. Question 23. The required clearance between a transformer’s oil-filled tank and combustible material is: A) 1 ft B) 2 ft C) 3 ft D) 4 ft Answer: C Explanation: NEC 450.21 requires a minimum 3-ft clearance for oil-filled transformers. Question 24. A 240-V, 20-kVA transformer serving a residential service must have its secondary overcurrent protection sized at what percent of the transformer's rated secondary current? A) 100% B) 115% C) 125%
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D) Article 422 Answer: A Explanation: Article 210 covers branch-circuit requirements, including bathroom receptacles. Question 28. A 30-A GFCI breaker is installed to protect a 120-V receptacle circuit in a garage. According to NEC, what is the maximum length of a flexible cord that can be used for a temporary receptacle on this circuit? A) 25 ft B) 50 ft C) 75 ft D) 100 ft Answer: B Explanation: NEC 590.4 limits temporary cord sets to 50 ft for receptacles on a 30 - A circuit. Question 29. In a hazardous (Class I, Division 2) area, which wiring method is permitted for power conductors? A) NM cable B) Rigid metal conduit (RMC) only C) Flexible metal conduit (FMC) with listed fittings D) Any wiring method listed for Class I, Division 2 Answer: D Explanation: Only wiring methods listed for the specific hazardous classification may be used. Question 30. The NEC classifies a location containing flammable gases as Class I. What does Division 1 indicate? A) Hazardous atmosphere present continuously or likely to exist frequently B) Hazardous atmosphere present only during maintenance
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C) No hazardous atmosphere present D) Only dust particles present Answer: A Explanation: Division 1 locations have a hazardous atmosphere that is present continuously or frequently. Question 31. Which NEC article contains the requirements for emergency lighting systems? A) Article 410 B) Article 700 C) Article 620 D) Article 680 Answer: B Explanation: Article 700 covers emergency systems, including emergency lighting. Question 32. A standby generator supplying a building must be connected to the load-side of the service disconnect. This requirement is found in which article? A) Article 230 B) Article 702 C) Article 705 D) Article 710 Answer: B Explanation: Article 702 governs standby power systems and requires connection on the load side. Question 33. For a photovoltaic (PV) array, the NEC requires a dedicated disconnecting means to be located where relative to the PV source? A) Within 5 ft of the array
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B) GFCI-protected, weather-proof, and listed for wet locations C) Two-pole, 240-V only D) Non-GFCI, recessed Answer: B Explanation: NEC 680.22 requires GFCI protection and a weather-proof enclosure for pool deck receptacles. Question 37. The required bonding conductor size for a 100-A service is: A) #10 AWG copper B) #8 AWG copper C) #6 AWG copper D) #4 AWG copper Answer: C Explanation: Table 250.66 indicates #6 AWG copper for a 100-A service grounding electrode conductor. Question 38. In a commercial building, the minimum required number of lighting circuits for a floor area of 5,000 ft², per NEC Table 220.42, is: A) 1 B) 2 C) 3 D) 4 Answer: B Explanation: Table 220.42 provides a minimum of 2 lighting circuits for up to 5,000 ft². Question 39. Which NEC article governs the installation of conduit bodies (C-type fittings)? A) Article 300
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B) Article 314 C) Article 352 D) Article 358 Answer: B Explanation: Article 314 covers boxes, conduit bodies, and fittings. Question 40. The NEC defines a “listed” product as one that has been: A) Approved by the local building department B) Tested and approved by a recognized testing agency C) Manufactured in the United States D) Installed by a licensed electrician Answer: B Explanation: “Listed” means the product has been evaluated by a recognized testing agency (e.g., UL). Question 41. For a raceway containing more than three current-carrying conductors, the NEC requires a derating factor. Which factor applies to six conductors? A) 80% B) 70% C) 65% D) 60% Answer: B Explanation: Table 310.15(B)(3)(a) shows a 70% factor for 4-6 conductors. Question 42. A 30-A, 240-V dryer circuit requires a neutral conductor. According to NEC, the neutral must be sized at least: A) 30 A
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B) Article 358 C) Article 362 D) Article 376 Answer: A Explanation: Article 352 covers PVC conduit (rigid, intermediate, and flexible). Question 46. The NEC requires that a receptacle installed in a laundry room be GFCI-protected. What is the minimum ampere rating for that receptacle? A) 15 A B) 20 A C) 30 A D) 40 A Answer: B Explanation: NEC 210.11(C)(2) requires a 20-A receptacle circuit in laundry areas. Question 47. A conduit fill calculation for a box with three #12 AWG THHN conductors and one device (switch) results in a total fill of: A) 30% B) 40% C) 50% D) 60% Answer: B Explanation: Each #12 THHN counts as 1 unit; a device counts as 2 units. Total units = 5. For a standard 1-in. box (max 40 % fill), 5 units = 40% fill. Question 48. Which NEC article governs the installation of fire alarm cable (type FPL)? A) Article 300
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B) Article 725 C) Article 800 D) Article 760 Answer: D Explanation: Article 760 includes fire alarm system wiring, including FPL cable. Question 49. For a 120/240-V single-phase motor, the NEC requires the branch-circuit short-circuit and ground-fault protective device to be sized at what percentage of the motor’s full-load current? A) 125% B) 150% C) 200% D) 250% Answer: D Explanation: NEC 430.22 mandates a protective device not less than 250 % of the motor’s FLC. Question 50. Which of the following is considered a “permanent wiring method” per NEC? A) Portable cord-and-plug B) Flexible metal conduit (FMC) C) Non-metallic sheathed cable (NM) D) Both B and C Answer: D Explanation: Both FMC and NM are listed as permanent wiring methods. Question 51. In a commercial building, the minimum number of 15-A receptacle circuits required for a 2,000 ft² office area is: A) 1
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Ultimate Exam
B) Article 725 C) Article 800 D) Article 590 Answer: B Explanation: Article 725 covers Class 2 and Class 3 power circuits. Question 55. The NEC permits the use of a “sleeve” as a raceway for protecting conductors in concrete. Which material is acceptable for this purpose? A) Rigid metal conduit (RMC) only B) PVC conduit only C) Any listed conduit material D) Flexible metal conduit only Answer: C Explanation: Any conduit listed for use as a concrete sleeve may be used. Question 56. For a 100-A residential service, the minimum size of the service-entrance conductors (copper) is: A) #6 AWG B) #4 AWG C) #2 AWG D) #1/0 AWG Answer: B Explanation: Table 310.15(B)(16) shows #4 AWG copper rated for 85 A; however, for a 100-A service, #4 AWG is acceptable with 75 °C rating. Question 57. Which NEC article governs the installation of underground feeder (UF) cable? A) Article 300
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B) Article 320 C) Article 340 D) Article 352 Answer: C Explanation: Article 340 covers underground feeder and underground service entrance cable. Question 58. The NEC requires that a receptacle serving a countertop in a kitchen be GFCI protected and have a minimum rating of: A) 15 A, 125 V B) 20 A, 125 V C) 20 A, 250 V D) 30 A, 125 V Answer: B Explanation: NEC 210.8(A)(6) requires 20-A, 125-V receptacles for kitchen countertops. Question 59. In a Class II, Division 2 hazardous location, which of the following wiring methods is permitted? A) NM cable B) Rigid metal conduit (RMC) with listed fittings C) Flexible non-metallic conduit (FNC) D) Any wiring method Answer: B Explanation: Only wiring methods listed for Class II, Division 2 (e.g., RMC) may be used. Question 60. The NEC requires that all metal raceways entering a hazardous location be sealed with a what?
