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Question 1. What is the unit of electrical resistance? A) Watt B) Ampere C) Ohm D) Volt Answer: C Explanation: The unit of electrical resistance is the ohm, which measures how much a material resists the flow of electric current. Question 2. According to Ohm’s Law, if voltage is 120V and resistance is 24Ω, what is the current? A) 5A B) 10A C) 0.2A D) 2A Answer: A Explanation: Ohm’s Law states I = V/R; 120V/24Ω = 5A. Question 3. Which formula best calculates electrical power? A) P = I × E B) P = R × E C) P = E ÷ I D) P = I + R Answer: A Explanation: Electrical power is calculated by multiplying current (I) by voltage (E). Question 4. What does RMS stand for in AC circuits?
A) Regular Maximum Signal B) Root Mean Square C) Resistance Measurement System D) Real Mean Signal Answer: B Explanation: RMS is Root Mean Square, a value representing the effective voltage or current in AC circuits. Question 5. What is the main difference between AC and DC? A) AC flows in one direction B) DC alternates direction C) AC alternates direction D) DC is used for household circuits Answer: C Explanation: AC (Alternating Current) changes direction periodically, while DC (Direct Current) flows in one direction. Question 6. Which of the following is a safety protocol for electrical work? A) Working with wet hands B) Lockout/Tagout C) Ignoring PPE D) Removing ground connections Answer: B Explanation: Lockout/Tagout is a procedure to ensure equipment is de-energized before maintenance. Question 7. What does PPE stand for in electrical safety?
B) Clamp-on ammeter C) Megger D) Wire stripper Answer: B Explanation: A clamp-on ammeter measures current without direct contact with conductors. Question 11. What is the minimum size of equipment grounding conductor for a 20A circuit? A) 8 AWG B) 12 AWG C) 10 AWG D) 14 AWG Answer: D Explanation: For a 20A circuit, the minimum grounding conductor size per NEC is 14 AWG copper. Question 12. What is required for system grounding? A) Bonding only B) Connection to an approved grounding electrode C) Use of neutral wire only D) No connection needed Answer: B Explanation: System grounding requires a connection to an approved grounding electrode. Question 13. What is the purpose of a Grounding Electrode Conductor (GEC)? A) To bond metal parts B) To provide path to earth
C) To supply voltage D) To increase resistance Answer: B Explanation: The GEC provides a low impedance path to earth to safely dissipate fault currents. Question 14. Which overcurrent protection device is most common in residential panels? A) Fuse B) Circuit breaker C) Transformer D) Relay Answer: B Explanation: Circuit breakers are the standard overcurrent protection device in residential panels. Question 15. What is the standard ampere rating for most residential lighting circuits? A) 20A B) 30A C) 15A D) 40A Answer: C Explanation: Most residential lighting circuits are rated at 15A. Question 16. What NEC article covers branch circuits? A) 210 B) 300 C) 408
Answer: B Explanation: Demand factor adjusts load calculations based on likely simultaneous usage. Question 20. Which conductor is identified by white insulation per NEC? A) Hot B) Ground C) Neutral D) Phase B Answer: C Explanation: Neutral (grounded) conductors are identified by white insulation. Question 21. What is the minimum conductor size for branch circuits in dwellings? A) 12 AWG B) 10 AWG C) 14 AWG D) 8 AWG Answer: C Explanation: The minimum size for branch circuits in dwellings is 14 AWG. Question 22. What is THHN insulation suitable for? A) Only wet locations B) Dry and damp locations C) Underground installations D) High voltage only Answer: B
Explanation: THHN is rated for dry and damp locations. Question 23. What is the maximum number of 90 - degree bends allowed in a conduit run between pull points? A) Two B) Four C) Six D) Three Answer: B Explanation: NEC allows a maximum of four 90-degree bends between pull points. Question 24. Which cable type is commonly used for residential wiring? A) MC B) NM C) AC D) THWN Answer: B Explanation: NM (nonmetallic sheathed cable) is most common in residential wiring. Question 25. What does a megger test? A) Voltage B) Current C) Insulation resistance D) Power Answer: C Explanation: A megger is used to test insulation resistance in wires and equipment.
Question 29. What is the maximum allowable box fill for a standard 4-inch square box? A) 8 conductors B) Calculated by volume C) 12 conductors D) Unlimited Answer: B Explanation: Box fill is determined by the box volume and number/type of conductors/devices. Question 30. What NEC article covers requirements for raceways? A) 210 B) 300 C) 404 D) 408 Answer: B Explanation: NEC Article 300 covers general wiring methods, including raceways. Question 31. What is the function of a bonding jumper? A) Provide overcurrent protection B) Connect non-current-carrying metal parts C) Increase voltage D) Decrease resistance Answer: B Explanation: Bonding jumpers connect non-current-carrying metal parts to ensure a continuous path to ground. Question 32. Which device is used to disconnect a motor from its source?
A) Transformer B) Controller C) Disconnect switch D) Capacitor Answer: C Explanation: A disconnect switch is required to isolate motors from power sources. Question 33. What is the main requirement for transformer vaults? A) No ventilation B) Fire resistance C) Only one exit D) Use of wood framing Answer: B Explanation: Transformer vaults must have fire-resistant construction as per NEC. Question 34. How are panelboards required to be installed? A) At any height B) With clear working space C) Without grounding D) With no labeling Answer: B Explanation: Panelboards require clear working space for safety and accessibility. Question 35. What is the purpose of AFCI protection? A) Prevent ground faults
C) Wiring Methods D) Load Calculations Answer: B Explanation: Chapter 6 of the NEC covers requirements for special equipment. Question 39. What is required for swimming pool wiring? A) NM cable B) GFCI protection C) No bonding D) Use of aluminum conductors Answer: B Explanation: Swimming pools require GFCI protection for outlets and equipment. Question 40. What does Article 404 cover? A) Panelboards B) Switches C) Raceways D) Transformers Answer: B Explanation: NEC Article 404 covers requirements for switches. Question 41. What is the minimum clearance in front of an electrical panelboard? A) 18 inches B) 24 inches C) 36 inches
D) 48 inches Answer: C Explanation: NEC requires 36 inches of clearance in front of panelboards. Question 42. Which symbol represents a ground connection on blueprints? A) Triangle B) Three horizontal lines C) Circle D) Square Answer: B Explanation: A ground connection is shown by three horizontal lines descending from a point. Question 43. What is the primary function of a fuse? A) Increase voltage B) Limit current C) Provide grounding D) Store energy Answer: B Explanation: A fuse protects circuits by interrupting current flow during overcurrent conditions. Question 44. Which device is used for insulation resistance testing? A) Megger B) Voltmeter C) Ammeter D) Ohmmeter
Explanation: Article 450 covers transformer installation and protection requirements. Question 48. What is required for elevator wiring? A) Flexible cable only B) Special NEC requirements C) NM cable D) No raceways Answer: B Explanation: Elevators have specific wiring requirements covered in the NEC for safety and reliability. Question 49. Which conductor insulation is rated for wet locations? A) THHN B) THWN C) NM D) AC Answer: B Explanation: THWN is suitable for wet locations per its rating. Question 50. What is the main function of an electrical panelboard? A) Store energy B) Distribute power C) Provide grounding D) Measure current Answer: B Explanation: Panelboards distribute power to branch circuits and feeders.
Question 51. What is the minimum burial depth for direct burial cable? A) 6 inches B) 12 inches C) 18 inches D) 24 inches Answer: C Explanation: The NEC requires a minimum of 18 inches for direct burial cable outdoors. Question 52. What type of conductor is required for service entrance? A) Aluminum only B) Copper or aluminum rated for service C) Only copper D) Bare wire Answer: B Explanation: Service entrance conductors can be copper or aluminum but must be rated for service use. Question 53. What is the main hazard of arc-flash? A) Electromagnetic interference B) Burns and injuries C) Increased voltage D) Insulation failure Answer: B Explanation: Arc-flash can cause severe burns and injuries due to high-energy electrical discharge.
A) Must be GFCI protected B) Regular outlets allowed C) No cover required D) Only 240V outlets Answer: A Explanation: Outdoor receptacles must be GFCI protected and have weatherproof covers. Question 58. What is the purpose of a disconnecting means for HVAC equipment? A) Ground the equipment B) Provide local shutoff C) Increase voltage D) Prevent load calculation Answer: B Explanation: A disconnecting means allows local shutoff for safety during servicing. Question 59. What is the required minimum wire size for a 30A dryer circuit? A) 10 AWG B) 12 AWG C) 14 AWG D) 8 AWG Answer: A Explanation: A 30A dryer circuit requires at least 10 AWG copper wire. Question 60. What is the main reason for using conduit? A) Increase resistance
B) Protect conductors C) Store energy D) Reduce voltage Answer: B Explanation: Conduit protects conductors from physical damage and environmental hazards. Question 61. What is required for bonding in swimming pool installations? A) Only grounding rod B) All metal parts bonded together C) No bonding needed D) Use of NM cable Answer: B Explanation: All metallic parts must be bonded to form an equipotential grid for safety. Question 62. What is the minimum number of receptacles required in a kitchen countertop space? A) One B) Two C) Based on spacing D) None Answer: C Explanation: Receptacles must be installed so no point is more than 24 inches from a receptacle. Question 63. What device is used to measure voltage? A) Clamp-on ammeter B) Voltmeter
