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2014 Ultimate Exam
Question 1. Which of the following units represents electrical resistance? A) Volts B) Amperes C) Ohms D) Watts Answer: C Explanation: Resistance is measured in ohms (Ω), defined by Ohm’s Law as V ÷ I. Question 2. Ohm’s Law states that V = I × R. If a circuit has 12 V across a 4 Ω resistor, what is the current? A) 2 A B) 3 A C) 0.33 A D) 48 A Answer: A Explanation: I = V/R = 12 V / 4 Ω = 3 A (correction: 12/4 = 3, so answer B). Question 3. In a series circuit with three resistors of 2 Ω, 3 Ω, and 5 Ω, the total resistance is: A) 10 Ω B) 5 Ω C) 3 Ω D) 2 Ω Answer: A
2014 Ultimate Exam
Explanation: Series resistance adds: 2 + 3 + 5 = 10 Ω. Question 4. For a parallel network of two 6 Ω resistors, the equivalent resistance is: A) 12 Ω B) 6 Ω C) 3 Ω D) 0 Ω Answer: C Explanation: 1/R_eq = 1/6 + 1/6 = 2/6 → R_eq = 6/2 = 3 Ω. Question 5. Kirchhoff’s Current Law (KCL) states that at any node: A) The sum of voltages equals zero. B) The sum of currents entering equals the sum leaving. C) Power is conserved. D) Resistance is constant. Answer: B Explanation: KCL is based on conservation of charge. Question 6. In a single-phase AC system, the relationship between apparent power (S), real power (P), and power factor (PF) is: A) S = P × PF B) P = S × PF C) PF = P ÷ S
2014 Ultimate Exam
A) 6.25 A
B) 12.5 A
C) 15 A
D) 20 A
Answer: B Explanation: I = P/V = 1500 W / 240 V = 6.25 A (correction: 1500/240 = 6.25 A, so answer A). Question 10. The percentage voltage drop allowed for feeder conductors serving sensitive electronic equipment is: A) 1% B) 2% C) 3% D) 5% Answer: B Explanation: NEC recommends limiting feeder voltage drop to 2% for sensitive loads. Question 11. A residential kitchen requires at least how many 20-A small-appliance branch circuits? A) One B) Two C) Three D) Four Answer: B
2014 Ultimate Exam
Explanation: NEC 210.11(C)(1) requires two 20-A circuits for countertop receptacles. Question 12. The minimum ampacity for a dedicated 30-A dryer circuit using copper conductors with 75 °C insulation is: A) 30 A B) 35 A C) 40 A D) 45 A Answer: A Explanation: The circuit must be rated for at least the load; 30 A breaker with 30 A-rated conductors is acceptable. Question 13. Which color is used for a grounded (neutral) conductor in a typical NM cable? A) Black B) Red C) White D) Green Answer: C Explanation: NEC designates white (or gray) for neutral conductors. Question 14. The required clearance between a service‐entrance conductor and a grounded metal water pipe is: A) 1 in. B) 2 in.
2014 Ultimate Exam
Question 17. A 125-V receptacle in a bathroom must be GFCI-protected. Which of the following also meets the requirement? A) Two-pole breaker only B) GFCI breaker C) AFCI breaker D) Standard receptacle with a fuse Answer: B Explanation: GFCI protection can be provided by a GFCI breaker or receptacle; a GFCI breaker satisfies the code. Question 18. The grounding electrode conductor (GEC) for a residential service is typically sized at: A) #4 AWG copper for a 100 A service B) #6 AWG copper for a 100 A service C) #8 AWG copper for a 100 A service D) #10 AWG copper for a 100 A service Answer: B Explanation: NEC Table 250.66 requires #6 AWG copper for a 100 A service. Question 19. A concrete-encased electrode (Ufer ground) must be at least what length of #4 AWG copper? A) 10 ft B) 20 ft C) 30 ft D) 40 ft
2014 Ultimate Exam
Answer: C Explanation: NEC 250.52(A)(3) requires a minimum of 20 ft of #4 copper; many jurisdictions adopt 30 ft for added safety. Question 20. The minimum size of an equipment grounding conductor (EGC) for a 20-A circuit using 12-AWG THHN copper is: A) #14 AWG B) #12 AWG C) #10 AWG D) #8 AWG Answer: A Explanation: Table 250.122 permits #14 AWG copper for a 15-A or 20-A circuit. Question 21. In a separate detached garage, the grounding electrode system must be: A) Connected to the house’s grounding electrode via a #12 AWG conductor. B) Independent and have its own grounding electrode. C) Omitted if the garage is only used for storage. D) Shared with the house’s neutral. Answer: B Explanation: NEC 250.32(A) requires a separate grounding electrode system for detached structures. Question 22. When derating conductors for ambient temperature of 40 °C, the adjustment factor for THHN copper (90 °C rating) is:
2014 Ultimate Exam
Question 25. The maximum recommended voltage drop for a feeder serving a 10 kW load at 240 V is: A) 1% B) 2% C) 3% D) 5% Answer: B Explanation: NEC recommends a 2% drop for feeders to maintain efficiency. Question 26. To limit voltage drop to 3% on a 200-ft run of 120-V lighting circuit drawing 15 A, the minimum copper conductor size is: A) #14 AWG B) #12 AWG C) #10 AWG D) #8 AWG Answer: C Explanation: Using voltage-drop formulas, #10 AWG keeps the drop within 3%. Question 27. The fill capacity for a 3/4-in. EMT conduit with #12 AWG THHN conductors is: A) 3 conductors B) 5 conductors C) 7 conductors
2014 Ultimate Exam
D) 9 conductors Answer: B Explanation: NEC Chapter 9 Table 1 and Table 5 give a 40% fill for EMT; #12 AWG occupies 0.0133 in², allowing 5 conductors. Question 28. The box fill calculation for a single-gang device box containing one switch, one ground, and one neutral counts as: A) 2 conductors B) 3 conductors C) 4 conductors D) 5 conductors Answer: B Explanation: Each ungrounded and neutral conductor counts as one unit; the equipment grounding conductor counts as 1/2 unit, but a device box already includes the internal clamp. Question 29. The maximum number of #14 AWG THHN conductors that may be placed in a 1-in. PVC conduit is: A) 12 B) 18 C) 24 D) 30 Answer: B Explanation: Using Table 5, #14 AWG area is 0.0133 in²; 40% of 1-in. PVC (0.533 in²) allows 18 conductors.
2014 Ultimate Exam
D) Run through a raceway the entire length. Answer: B Explanation: NEC 334.30 mandates securing NM cable within 8 in. of boxes and at intervals not exceeding 4.5 ft. Question 33. The maximum number of NM-B cables allowed in a 2-in. PVC conduit is: A) 2 B) 3 C) 4 D) 5 Answer: C Explanation: Using Table 5 for NM-B (approx. 0.2 in² per cable), 40% of 2-in. conduit (0.533 in²) permits about 4 cables. Question 34. A metal-clad (MC) cable must be terminated in a: A) Plastic box only. B) Metal box with a grounding screw. C) Wooden box. D) Any type of enclosure. Answer: B Explanation: MC cable has an integral grounding conductor and requires a metal enclosure with a grounding point.
2014 Ultimate Exam
Question 35. The required spacing between supports for a 1-in. Rigid Metal Conduit (RMC) is: A) 6 ft B) 8 ft C) 10 ft D) 12 ft Answer: C Explanation: NEC 380.30 requires RMC to be supported within 3 ft of each box and at intervals not exceeding 10 ft. Question 36. For a 3-phase, 4-wire feeder supplying a commercial building, the neutral conductor may be: A) Smaller than the phase conductors. B) Same size as the phase conductors. C) Larger than the phase conductors. D) Omitted if load is balanced. Answer: B Explanation: NEC 215.2 requires the neutral to be the same size as the phase conductors unless calculated otherwise. Question 37. A 30-A GFCI circuit breaker protects a receptacle in a wet location. What is the minimum rating for the receptacle? A) 15 A B) 20 A C) 30 A
2014 Ultimate Exam
Question 40. The required clearance between a service disconnect and a water pipe that is used as a grounding electrode is: A) 0 in. – they may touch. B) 1 in. C) 2 in. D) 4 in. Answer: A Explanation: The grounding electrode (water pipe) may be directly bonded to the service disconnect; no clearance is required. Question 41. In a hazardous location classified as Class I, Division 2, which type of wiring is permitted? A) Type NM-B cable. B) Rigid metal conduit only. C) Listed explosion-proof conduit and fittings. D) Any wiring as long as it is insulated. Answer: C Explanation: Division 2 areas require equipment that can contain an explosion; only listed explosion-proof wiring methods are allowed. Question 42. The required grounding conductor size for a 100-A feeder using copper conductors with a 75 °C rating is: A) #8 AWG B) #6 AWG C) #4 AWG
2014 Ultimate Exam
D) #2 AWG
Answer: B Explanation: Table 250.122 lists #6 AWG copper for a 100-A circuit; #8 AWG is insufficient. Question 43. When a motor is rated at 5 hp, 460 V, 3-phase, the minimum size of the branch-circuit conductors (copper) is: A) #10 AWG B) #8 AWG C) #6 AWG D) #4 AWG Answer: D Explanation: NEC 430.22 requires conductors sized to at least 125 % of motor full-load current; a 5 hp 460 V motor typically draws ~7.2 A, so #6 AWG is minimum, but many jurisdictions round up to #4 AWG for safety. Question 44. The short-circuit protection for a motor branch circuit must be selected not to exceed: A) 250 % of the motor FLC. B) 300 % of the motor FLC. C) 400 % of the motor FLC. D) 500 % of the motor FLC. Answer: B Explanation: NEC 430.32 allows a maximum of 300 % for inverse-time circuit breakers on motors.
2014 Ultimate Exam
C) 30 A, 120 V.
D) 15 A, 277 V.
Answer: B Explanation: NEC 517.13 requires a dedicated 20-A branch circuit for fire alarm equipment. Question 48. The required grounding electrode for a new residential building in Montana must be installed: A) Within 5 ft of the service disconnect. B) At least 8 ft deep if a ground rod is used. C) Only if the soil resistivity is above 100 Ω·cm. D) Not required if a metal water pipe is present. Answer: B Explanation: NEC 250.53(A)(1) specifies ground rods be at least 8 ft long and driven vertically. Question 49. For a 120/240-V single-phase service, the neutral conductor may be: A) Shared with other services. B) Bonded to the grounded conductor only at the service equipment. C) Bonded at every disconnect. D) Omitted if a 4-wire feeder is used. Answer: B Explanation: NEC 250.24(A) requires neutral and ground to be bonded only at the service disconnect.
2014 Ultimate Exam
Question 50. The required conduit fill for a 2-in. EMT containing three 3/0 AWG conductors (90 °C) is: A) 30% B) 40% C) 50% D) 60% Answer: B Explanation: EMT conduit is limited to 40% fill for more than two conductors. Question 51. Which of the following is the correct method to calculate the demand factor for a dwelling’s lighting load? A) 100 % of the total connected load. B) 3 VA per square foot, multiplied by 0.8. C) 120 VA per square foot, multiplied by 0.3. D) 3 VA per square foot, multiplied by 0.3. Answer: D Explanation: NEC Table 220.42 uses 3 VA per ft² for general lighting, multiplied by 0.3 for dwellings. Question 52. The minimum size of a grounding electrode conductor for a 400-A service is: A) #6 AWG copper B) #4 AWG copper C) #2 AWG copper
