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Journeyman Electrician
Ultimate Exam
Question 1. Which equation correctly represents Ohm’s Law for a residential branch circuit? A) V = I × R B) I = V ÷ R C) P = V × I D) All of the above Answer: D Explanation: Ohm’s Law states V = I × R, and rearranging gives I = V ÷ R. The power formula P = V × I is also derived from Ohm’s Law, so all three are correct. Question 2. A 15-amp circuit supplies a 120-V receptacle. What is the maximum continuous load in watts that may be placed on this circuit according to NEC 210.20(A)? A) 1,800 W B) 1,440 W C) 2,000 W D) 1,560 W Answer: B Explanation: Continuous loads must not exceed 80 % of the breaker rating. 15 A × 120 V × 0.8 = 1,440 W. Question 3. For a 100-ft run of 12-AWG copper NM cable feeding a 120-V load, the calculated voltage drop is 2.5 %. Is this acceptable? A) Yes, because it is ≤ 3 % B) No, because it exceeds 2 % C) Yes, because voltage drop is not limited for lighting loads D) No, because any drop > 1 % is unacceptable
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Ultimate Exam
Answer: A Explanation: NEC permits up to 3 % voltage drop for branch circuits; 2.5 % is within the limit. Question 4. According to Article 220, what is the general lighting load factor for a dwelling unit? A) 3 VA per square foot B) 4 VA per square foot C) 5 VA per square foot D) 6 VA per square foot Answer: B Explanation: NEC 220.12 requires 3 VA per ft² for the first 3,000 ft² and 4 VA per ft² for any area above that. The common design value for most homes is 3 VA/ft², but the code’s default “general lighting load” is 3 VA per ft²; however, the calculation for the first 3,000 ft² uses 3 VA, and the remainder uses 4 VA. For exam purposes the standard answer is 3 VA, but the question asks “general lighting load factor” which the NEC lists as 3 VA/ft². The correct answer is therefore A. (Correction applied: the correct answer is A.) Question 5. A dwelling has 2,200 ft² of habitable floor area. What is the calculated general lighting load in VA? A) 6,600 VA B) 8,800 VA C) 7,200 VA D) 9,200 VA Answer: A Explanation: 2,200 ft² × 3 VA/ft² = 6,600 VA.
Journeyman Electrician
Ultimate Exam
D) Use the highest single-phase current Answer: C Explanation: The neutral current is calculated as the vector sum of the three phase currents, often using the √3 method for balanced loads. Question 9. What is the minimum clearance required between a service drop and a driveway in Missouri? A) 6 ft B) 8 ft C) 10 ft D) 12 ft Answer: C Explanation: NEC 230.24 requires a minimum of 10 ft horizontal clearance over a driveway. Question 10. A residential service entrance uses 4/0 AWG aluminum conductors on a 200-A service. Is this conductor size acceptable per NEC Table 310.15(B)(16)? A) Yes, 4/0 AL is rated for 180 A only B) No, it must be 250 A rated C) Yes, because 4/0 AL is rated for 205 A at 75 °C D) No, copper must be used for 200 A Answer: C Explanation: 4/0 AL at 75 °C is rated for 205 A, which satisfies a 200-A service. Question 11. What is the required working space in front of a service equipment panel according to NEC 110.26?
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Ultimate Exam
A) 30 in wide × 36 in deep × 6 ft high B) 36 in wide × 30 in deep × 6 ft high C) 30 in wide × 30 in deep × 6 ft high D) 36 in wide × 36 in deep × 6 ft high Answer: A Explanation: NEC requires a minimum clear working space of 30 in wide, 36 in deep, and 6 ft high. Question 12. The main service disconnect must be located: A) Inside the building only B) Outside the building only C) Either inside or outside, but readily accessible D) Within 10 ft of the service entrance Answer: C Explanation: NEC 230.71 requires the main disconnect to be readily accessible, either inside or outside the building. Question 13. Which grounding electrode is considered the most reliable for a new residential construction? A) Metal water pipe B) Concrete-encased electrode (Ufer) C) Ground rod D) Metal underground tank Answer: B Explanation: A concrete-encased electrode provides a low-impedance path and is required for new construction per NEC 250.52(A)(3).
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Answer: B Explanation: NEC 334.30 requires NM cable be supported within 12 in of each box and at intervals not exceeding 4.5 ft. Question 17. NM cable is prohibited in which of the following locations? A) Interior walls of a dwelling B) Crawl spaces with a floor height less than 18 in above grade C) Attics with a minimum clearance of 6 in from the roof deck D) Finished basements Answer: B Explanation: NM cable cannot be installed in crawl spaces that are less than 18 in high because of moisture exposure. Question 18. What is the maximum number of #12 AWG THHN conductors that may be placed in a 1-in. EMT conduit according to NEC Annex C? A) 9 B) 12 C) 15 D) 18 Answer: B Explanation: Annex C Table C1 shows that a 1-in. EMT can hold up to 12 #12 AWG conductors (40 % fill). Question 19. A junction box contains three #12 AWG insulated conductors, one #12 AWG equipment grounding conductor, and a single-pole switch. What is the minimum volume of the box? (Use 2.25 in³ per conductor volume)
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Ultimate Exam
A) 13.5 in³ B) 15.0 in³ C) 18.0 in³ D) 20.0 in³ Answer: C Explanation: Conductors count: 3 (current-carrying) + 1 (ground) = 4 × 2.25 in³ = 9 in³. The switch counts as one conductor volume, adding 2.25 in³ → total 11.25 in³. However, a device (switch) requires one additional conductor volume, bringing total to 13.5 in³. Since the nearest listed size ≥ required is 15.0 in³, the correct answer is B. (Correction applied: answer B.) Question 20. Which of the following wiring methods requires a bonding jumper inside the conduit for metallic raceways? A) AC cable B) MC cable C) EMT conduit D) NM cable Answer: C Explanation: Metal raceways such as EMT must be bonded to the grounding system with a bonding jumper or by using a metal-clad conduit system. Question 21. In a kitchen, the required receptacle spacing along a countertop is: A) No farther than 24 in apart B) No farther than 30 in apart C) No farther than 36 in apart D) No farther than 48 in apart
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C) Only in garages D) Only in unfinished basements Answer: A Explanation: NEC 406.12 requires TRR in all 125-V, 15- and 20-A receptacles in dwelling units. Question 25. Which lighting control is required in habitable rooms to meet NEC 210.70(A)(1)? A) A three-way switch B) A wall switch controlling the lighting C) A motion sensor switch D) A dimmer switch Answer: B Explanation: NEC requires a wall-mounted switch to control lighting in habitable rooms. Question 26. For a swimming pool pump motor (1 hp, 240 V), what is the minimum size of the grounding conductor required? A) 12 AWG copper B) 10 AWG copper C) 8 AWG copper D) 6 AWG copper Answer: C Explanation: A 1-hp motor on a 240-V circuit typically uses a 30-A breaker; Table 250.122 calls for an 8-AWG copper EGC for a 30-A OCPD.
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Question 27. According to Article 680, what is the required distance from a pool wall to the nearest GFCI-protected receptacle? A) 3 ft B) 5 ft C) 6 ft D) 8 ft Answer: C Explanation: NEC 680.22 requires receptacles within 6 ft of the pool wall to be GFCI protected. Question 28. When sizing overcurrent protection for a 3-ton, 240-V residential air-conditioning unit, which factor must be applied to the nameplate current? A) 125 % B) 150 % C) 175 % D) 200 % Answer: A Explanation: NEC 440.6 requires a minimum of 125 % of the nameplate current for air-conditioning equipment. Question 29. A 1-ph, 120-V, 10-hp sump pump requires a dedicated branch circuit. What is the minimum ampacity of the feeder conductors? A) 15 A B) 20 A C) 30 A D) 40 A
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B) 1.5 cal/cm² C) 4 cal/cm² D) 8 cal/cm² Answer: B Explanation: The arc-flash boundary is defined where the incident energy equals 1.5 cal/cm², the level at which a second-degree burn can occur. Question 33. In Missouri, the rough-in inspection for residential wiring must be performed: A) After the drywall is installed B) Before any insulation is placed C) After all wiring is secured and before covering with finish materials D) Only after final fixture installation Answer: C Explanation: Rough-in inspection occurs after wiring is completed and secured, but before walls are finished. Question 34. On a residential electrical plan, the symbol “⎕” typically indicates: A) A receptacle B) A light fixture C) A switch D) A panelboard Answer: B Explanation: The standard symbol for a ceiling-mounted light fixture is a circle with a cross (⎕).
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Question 35. Which of the following is NOT a permitted use for Type MC cable in a residential dwelling? A) Exposed in a basement B) Within a conduit in a wet location C) In a soffit above a garage D) In a suspended ceiling Answer: D Explanation: Type MC is not allowed in a suspended ceiling that is classified as a “dry” location without additional protection. Question 36. For a 120/240-V, 3-wire feeder supplying a subpanel, what is the minimum size of the grounding electrode conductor (GEC) if the feeder OCPD is 100 A? A) 8 AWG copper B) 6 AWG copper C) 4 AWG copper D) 2 AWG copper Answer: B Explanation: NEC Table 250.66 requires a 6-AWG copper GEC for a 100-A feeder. Question 37. A 20-amp, 120-V GFCI receptacle is installed in a bathroom. Which of the following statements is true? A) The receptacle must be the first device on the branch circuit B) The GFCI can protect downstream outlets on the same circuit C) The receptacle cannot be used for a hair dryer D) The GFCI must be a two-pole device
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A) One B) Two C) Three D) Four Answer: B Explanation: NEC 210.8(A)(2) requires at least two 20-A GFCI receptacles in a garage. Question 41. The required minimum size of a grounding electrode (Ufer) for a new single-family home is: A) ½-in. diameter × 4 ft length B) ¾-in. diameter × 4 ft length C) ½-in. diameter × 8 ft length D) ¾-in. diameter × 8 ft length Answer: D Explanation: NEC 250.52(A)(3) requires a minimum ¾-in. diameter, 8-ft length concrete-encased electrode. Question 42. In a residential system, the neutral conductor must be: A) Isolated from the grounding system at the main panel only B) Bonded at every subpanel C) Connected to the equipment grounding conductor throughout the house D) None of the above Answer: A
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Explanation: The neutral is bonded to ground only at the service disconnect; downstream subpanels must keep neutral and ground isolated. Question 43. Which of the following is the correct method to calculate the ampacity of a feeder conductor supplying a continuous load? A) Use the nameplate rating of the load B) Multiply the load current by 1. C) Divide the load current by 0. D) Both B and C are correct Answer: D Explanation: Multiplying by 1.25 and dividing by 0.8 are mathematically equivalent and both satisfy the 125 % continuous-load rule. Question 44. The NEC permits the use of a 12-AWG copper circuit for a 20-A receptacle circuit if: A) The circuit supplies only lighting loads B) The circuit is protected by a 20-A breaker C) The circuit is a dedicated appliance circuit D) None of the above Answer: B Explanation: 12-AWG copper is rated for 20 A and may be used on a 20-A circuit protected by a 20-A breaker. Question 45. Which of the following is a required feature of a residential main service panel? A) A main breaker rated no higher than 400 A B) A minimum of 12 circuit spaces
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Explanation: NEC 230.71 requires a minimum of 4 ft clearance in front of a service disconnect to allow vehicle movement. Question 48. A 120-V, 15-A bathroom receptacle must be GFCI protected. Which device can provide this protection? A) A two-pole breaker at the panel B) A GFCI receptacle at the outlet C) A standard receptacle with a separate GFCI breaker D) Both B and C Answer: D Explanation: Both a GFCI receptacle and a GFCI breaker can provide required protection. Question 49. Which NEC article governs the installation of receptacles in damp or wet locations? A) 210. B) 300. C) 410. D) 680. Answer: A Explanation: NEC 210.8 outlines GFCI requirements for damp and wet locations. Question 50. The required grounding conductor size for a 60-A feeder using copper conductors is: A) 12 AWG B) 10 AWG C) 8 AWG
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D) 6 AWG
Answer: B Explanation: Table 250.122 calls for a 10-AWG copper EGC for a 60-A circuit. Question 51. In a residential attic, the minimum clearance between the top of a recessed luminaire and the roof deck is: A) 1 in B) 3 in C) 6 in D) 12 in Answer: C Explanation: NEC 410.116 requires at least 6 in clearance between recessed fixtures and the roof deck. Question 52. Which of the following is a permissible method for protecting NM cable in a garage where it is exposed to physical damage? A) Installing the cable in PVC conduit B) Using armored cable (AC) instead of NM C) Both A and B D) None of the above Answer: C Explanation: Both encasing NM in conduit or replacing it with AC are acceptable ways to protect against physical damage. Question 53. A 240-V, 30-A dryer circuit requires a minimum conduit size of:
