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Question 1. In a series DC circuit with a 12 V source and two resistors of 4 Ω and 8 Ω, what is the current flowing through the circuit? A) 0.5 A B) 1 A C) 1.5 A D) 2 A Answer: B Explanation: Total resistance = 4 Ω + 8 Ω = 12 Ω; I = V/R = 12 V/12 Ω = 1 A. Question 2. For a parallel DC network of three 6 Ω resistors connected across a 24 V source, the total resistance is: A) 2 Ω B) 4 Ω C) 12 Ω D) 18 Ω Answer: A Explanation: 1/R_total = 1/6+1/6+1/6 = 3/6 = 0.5 → R_total = 2 Ω. Question 3. The RMS value of a sinusoidal voltage with a peak of 170 V is: A) 85 V B) 120 V C) 170 V D) 240 V Answer: B Explanation: V_RMS = V_peak/√2 = 170/1.414 ≈ 120 V. Question 4. The form factor of a pure sine wave is: A) 0.707 B) 1.0 C) 1.111 D) 1. Answer: C Explanation: Form factor = V_RMS / V_average = 1.111 for a sine wave. Question 5. Inductive reactance (X_L) at 60 Hz for a 0.2 H coil is: A) 7.54 Ω B) 12.57 Ω C) 25.13 Ω D) 31.42 Ω Answer: C Explanation: X_L = 2πfL = 2π·60·0.2 ≈ 25.13 Ω.
Question 6. Capacitive reactance (X_C) of a 10 μF capacitor at 50 Hz equals: A) 0.32 Ω B) 3.18 Ω C) 31.8 Ω D) 318 Ω Answer: C Explanation: X_C = 1/(2πfC) = 1/(2π·50·10 × 10⁻⁶) ≈ 31.8 Ω. Question 7. In a balanced three‑phase wye system, the line‑to‑neutral voltage is 120 V. What is the line‑to‑line voltage? A) 120 V B) 208 V C) 240 V D) 277 V Answer: B Explanation: V_LL = √3 × V_LN = 1.732 × 120 ≈ 208 V. Question 8. A three‑phase delta connection has a line voltage of 480 V. What is the phase voltage? A) 277 V B) 480 V C) 831 V D) 1 kV Answer: A Explanation: In delta, V_phase = V_line / √3 = 480/1.732 ≈ 277 V. Question 9. The real power (P) in a single‑phase circuit with 120 V, 10 A, and a power factor of 0.8 lagging is: A) 600 W B) 720 W C) 960 W D) 1 200 W Answer: B Explanation: P = V × I × PF = 120 × 10 × 0.8 = 960 W (Oops, correct value is 960 W). Actually answer should be C. Correct Answer: C Explanation: Real power = 120 V × 10 A × 0.8 = 960 W. Question 10. Apparent power (S) for the same circuit in Question 9 is:
Question 14. Before using a hot stick, the lineman must perform which test to verify dielectric integrity? A) Visual inspection B) Pressure test C) Insulation resistance test D) Continuity test Answer: C Explanation: An insulation resistance (megohmmeter) test confirms the stick’s dielectric strength. Question 15. Which PPE item protects against arc‑flash exposure of 30 cal/cm²? A) Class 00 gloves B) FR‑rated coveralls (Category 2) C) Hard hat only D) Safety glasses Answer: B Explanation: FR‑rated (Flame‑Resistant) clothing rated for at least 30 cal/cm² is required. Question 16. The proper method to create an equipotential grounding point on a live pole is to:** A) Connect a rubber glove to the pole B) Attach a grounding strap to the pole and the lineman’s tool C) Use a wooden pole as a barrier D) Place a wooden block under the pole Answer: B Explanation: An equipotential strap equalizes potential between the worker and the energized part. Question 17. When rigging a 2‑ton load with a wire rope, the minimum safety factor required by OSHA is:** A) 2 B) 4 C) 5 D) 6 Answer: D Explanation: OSHA requires a safety factor of 6 for wire‑rope rigging. Question 18. In a pole‑top rescue, the primary step after a lineman is suspended is to:** A) Pull him up immediately B) Secure a rescue line to a stable anchor C) Cut the power D) Call emergency services Answer: B
Explanation: A rescue line must be attached to a secure anchor before lifting the victim. Question 19. The recommended depth for setting a 30‑ft wooden pole in sand is:** A) 2 ft B) 3 ft C) 4 ft D) 5 ft Answer: B Explanation: General practice calls for a depth of 1/10 of pole length; 30 ft × 0.1 = 3 ft. Question 20. When installing a steel pole, the raking angle should be:** A) 5° B) 10° C) 15° D) 20° Answer: C Explanation: Steel poles are typically raked 15° from vertical for stability. Question 21. The sag of a 400 ft, 12 mm ACSR conductor under a temperature rise of 30 °C is calculated using:** A) Catenary formula B) Linear approximation C) Ohm’s law D) Power factor equation Answer: A Explanation: Conductor sag is determined by the catenary (parabolic) equation. Question 22. A dynamometer reading of 250 lb on a 12 mm ACSR conductor indicates:** A) Proper tension B) Under‑tension C) Over‑tension D) No tension Answer: B Explanation: Typical tension for that conductor is ~300 lb; 250 lb is below spec. Question 23. The purpose of a suspension insulator on a distribution line is to:** A) Provide mechanical support only B) Conduct electricity C) Insulate and support the conductor D) Ground the line
A) Same kVA rating only B) Same voltage ratio and polarity C) Same manufacturer D) Same tap setting only Answer: B Explanation: Identical voltage ratios and correct polarity ensure load sharing. Question 29. Additive polarity in transformer connections means the:** A) Primary and secondary windings are wound opposite B) Voltages add when series‑connected C) Phase rotation reverses D) No effect on voltage Answer: B Explanation: Additive polarity causes the secondary voltage to add to the primary when connected in series. Question 30. The turns ratio of a transformer that steps 12 kV down to 480 V is:** A) 10:1 B) 20:1 C) 25:1 D) 30: Answer: C Explanation: Ratio = 12 000 V / 480 V = 25 : 1. Question 31. In a substation, a recloser is primarily used to:** A) Increase voltage B) Automatically close after a temporary fault C) Provide grounding D) Measure current Answer: B Explanation: Reclosers attempt to restore service after transient faults. Question 32. An oil‑filled transformer uses which cooling method as the first stage?** A) Forced air B) Natural convection (ONAN) C) Water cooling D) Direct oil spray Answer: B Explanation: ONAN (Oil Natural Air Natural) is the basic cooling mode for oil‑filled transformers.
Question 33. The dielectric strength of transformer oil is typically measured in:** A) volts per mil B) kilovolts per inch C) megohms D) amperes Answer: B Explanation: Dielectric strength is expressed as kV per inch of oil gap. Question 34. A primary underground cable is rated 35 kV, 150 A. The minimum conduit size required by the NEC is:** A) 1 in. B) 1‑¼ in. C) 1‑½ in. D) 2 in. Answer: C Explanation: NEC Table 352.30 requires at least 1‑½ in. conduit for that ampacity. Question 35. When splicing a 4/0 AWG copper conductor, the recommended minimum burial depth in residential areas is:** A) 12 in. B) 18 in. C) 24 in. D) 30 in. Answer: C Explanation: NEC 300.5 requires 24 in. depth for 4/0 AWG in most residential settings. Question 36. Thumping equipment for fault location works by:** A) Sending high‑frequency AC → detects reflections B) Applying DC voltage → measures resistance C) Generating ultrasonic sound → listening for leaks D) Using magnetic fields → detecting hot spots Answer: A Explanation: Thumpers inject a high‑frequency signal; faults cause reflections that are heard. Question 37. Radar fault locators determine the distance to a fault by measuring:** A) Voltage drop B) Time‑of‑flight of a pulse C) Current magnitude D) Temperature rise Answer: B
Answer: B Explanation: Only the faulted phase and the ground carry fault current. Question 43. In a three‑phase fault (line‑to‑line‑to‑ground), the fault current is approximately:** A) 1× I_phase B) √2 × I_phase C) √3 × I_phase D) 3 × I_phase Answer: C Explanation: For a L‑L‑G fault, the current is √3 times the phase current. Question 44. A megger reading of 2 MΩ on a 15 kV line indicates:** A) Good insulation B) Poor insulation C) Open circuit D) Short circuit Answer: B Explanation: For high‑voltage lines, insulation resistance should be > 10 MΩ; 2 MΩ is insufficient. Question 45. The most common cause of a blown T‑type fuse in a distribution feeder is:** A) Overvoltage B) Short‑circuit fault C) Mechanical vibration D) Weather exposure Answer: B Explanation: T‑type fuses protect against short‑circuit currents. Question 46. When using a voltage regulator on a feeder, the primary purpose is to:** A) Reduce current B) Maintain voltage within limits C) Increase power factor D) Provide grounding Answer: B Explanation: Voltage regulators adjust taps to keep feeder voltage steady. Question 47. The correct sequence for operating a pole‑top circuit breaker is:** A) Pull, close, lock B) Lock, pull, close C) Close, pull, lock D) Pull, lock, close
Answer: D Explanation: Pull the handle, lock it in the open position, then close when safe. Question 48. An air‑break switch is distinguished from a circuit breaker because it:** A) Does not interrupt current B) Has faster operation C) Is used only in substations D) Provides arc‑flash protection Answer: A Explanation: Air‑break switches open only when current is zero; they do not break load current. Question 49. The standard color code for a 12 kV phase conductor in the U.S. is:** A) Red B) Black C) Brown D) Orange Answer: D Explanation: 12 kV phases are typically orange per ANSI standards. Question 50. A lineman must wear a hard hat with a Class E rating when working near:** A) Low‑voltage circuits B) High‑voltage lines above 35 kV C) Mechanical hazards only D) Thermal hazards only Answer: B Explanation: Class E hard hats are rated for electrical protection up to 35 kV. Question 51. The minimum distance between a 13.8 kV line and a grounded metal fence is:** A) 3 ft B) 6 ft C) 9 ft D) 12 ft Answer: C Explanation: NESC Table 310‑2 requires 9 ft clearance for 13.8 kV. Question 52. When rigging a load using a sling, the angle between the sling legs should not exceed:**
Question 57. In a three‑phase Y‑connected load, the neutral current is:** A) Zero for balanced loads B) Equal to line current C) √3 times line current D) Half line current Answer: A Explanation: Balanced Y loads have equal phase currents that sum to zero in the neutral. Question 58. The term “form factor” is defined as:** A) RMS/average B) Peak/average C) Average/RMS D) Peak/RMS Answer: A Explanation: Form factor = V_RMS / V_average. Question 59. The voltage drop across a 0.5 Ω resistor carrying 20 A is:** A) 5 V B) 10 V C) 15 V D) 20 V Answer: B Explanation: V = I × R = 20 A × 0.5 Ω = 10 V. Question 60. The purpose of a reactor in a distribution line is to:** A) Increase real power B) Limit fault current C) Provide grounding D) Reduce voltage drop Answer: B Explanation: Reactors add inductive reactance to limit short‑circuit currents. Question 61. A lineman must use a voltage detector that is rated for at least:** A) 600 V B) 1 kV C) 5 kV D) 10 kV Answer: D Explanation: Detecting high‑voltage lines safely requires a detector rated ≥ 10 kV.
Question 62. The correct method to de‑energize a circuit before work is:** A) Pull the fuse only B) Open the breaker and verify with a meter C) Turn off the main switch only D) Rely on a coworker’s observation Answer: B Explanation: Opening the breaker and confirming absence of voltage ensures safety. Question 63. When measuring resistance of a long underground cable, the preferred instrument is:** A) Digital multimeter B) Megger C) Clamp‑on ammeter D) Oscilloscope Answer: B Explanation: A megger provides high‑voltage insulation resistance measurement. Question 64. The typical lifespan of a fiberglass hot stick, if properly maintained, is:** A) 2 years B) 5 years C) 10 years D) 15 years Answer: C Explanation: With regular inspection, hot sticks can last about a decade. Question 65. The standard size for a 25 kV service drop conductor is:** A) 4/0 AWG B) 250 MCM C) 500 MCM D) 750 MCM Answer: B Explanation: 250 MCM is commonly used for 25 kV service drops. Question 66. A lineman must check the phase rotation of a three‑phase source before connecting a motor. The correct rotation for a clockwise sequence is:** A) A‑B‑C B) A‑C‑B C) B‑A‑C D) C‑B‑A Answer: A Explanation: A‑B‑C denotes a clockwise (positive) phase sequence.
Answer: B Explanation: Connecting the tool to an equipotential ground equalizes its voltage with the line. Question 72. In a balanced three‑phase load, the total apparent power S is:** A) √3 × V_line × I_line B) V_line × I_line C) 3 × V_phase × I_phase D) Both A and C (they are equivalent) Answer: D Explanation: For balanced three‑phase, S = √ 3 V_LL I_L = 3 V_phase I_phase. Question 73. The primary purpose of a surge arrester on a transmission line is to:** A) Increase voltage B) Limit over‑voltage transients C) Reduce current D) Provide grounding only Answer: B Explanation: Surge arresters clamp voltage spikes caused by lightning or switching. Question 74. When installing a ground rod, the minimum driving depth is:** A) 4 ft B) 6 ft C) 8 ft D) 10 ft Answer: B Explanation: NEC requires ground rods to be at least 6 ft long. Question 75. The correct method to test a circuit breaker for proper operation is to:** A) Visually inspect contacts B) Perform a trip test with a calibrated test set C) Measure resistance across terminals D) Listen for audible click only Answer: B Explanation: A calibrated trip test confirms the breaker opens at its rated current. Question 76. A lineman must wear protective eyewear that meets which standard?**
A) ANSI Z87.1 B) OSHA 1910.133 C) NFPA 70E D) All of the above Answer: D Explanation: All listed standards address eye protection for electrical work. Question 77. The minimum conductor size for a 200 A feeder in copper is:** A) 2/0 AWG B) 4/0 AWG C) 250 MCM D) 300 MCM Answer: B Explanation: NEC Table 310.15(B)(16) lists 4/0 AWG copper for 200 A. Question 78. In a delta‑connected transformer, the line current is:** A) Equal to phase current B) √3 × phase current C) ½ × phase current D) 2 × phase current Answer: B Explanation: For delta, I_line = √3 × I_phase. Question 79. The safety rule “Never work on or near live parts without proper PPE” is classified as which Life‑Saving Rule?** A) Rule 1 B) Rule 2 C) Rule 3 D) Rule 4 Answer: A Explanation: Rule 1 of the lineman Life‑Saving Rules addresses PPE and live‑line safety. Question 80. A phase‑to‑ground fault on a 12 kV system will cause the fault voltage on the faulted phase to be approximately:** A) 0 V B) 6 kV C) 12 kV D) 24 kV Answer: B Explanation: Fault voltage is roughly half the system voltage (12 kV/2 ≈ 6 kV) due to the impedance of the neutral path.
Explanation: Ground fault relays sense residual (zero‑sequence) current. Question 86. The correct wire‑rope inspection interval for rigging is:** A) Every use B) Daily C) Weekly D) Monthly Answer: A Explanation: Wire‑rope must be inspected before each use for damage. Question 87. The minimum burial depth for a 13.2 kV underground cable in a roadway is:** A) 12 in. B) 18 in. C) 24 in. D) 30 in. Answer: C Explanation: NEC 300.5 requires 24 in. for 13.2 kV in a public right‑of‑way. Question 88. A pad‑mount switchgear is typically rated for which voltage class?** A) 2.4 kV B) 13.8 kV C) 34.5 kV D) 69 kV Answer: B Explanation: Pad‑mount units are common at 13.8 kV distribution level. Question 89. The primary protection for a transformer against over‑current is usually a:** A) Fuse B) Circuit breaker C) Recloser D) Surge arrester Answer: B Explanation: Circuit breakers provide instantaneous over‑current protection. Question 90. The minimum distance a lineman must stay from a live line while using a hot stick is:** A) 3 ft B) 6 ft C) 10 ft D) 12 ft Answer: D
Explanation: OSHA requires at least 12 ft clearance when working with live parts. Question 91. The neutral conductor in a wye‑connected system carries:** A) No current under any condition B) Only unbalanced load current C) Full line current D) Fault current only Answer: B Explanation: Neutral carries the vector sum of phase currents; only unbalanced currents flow. Question 92. The maximum allowable temperature rise for transformer oil under load is:** A) 25 °C B) 50 °C C) 75 °C D) 100 °C Answer: B Explanation: Standard design limits oil temperature rise to 50 °C above ambient. Question 93. The standard test voltage for a megger when checking a 15 kV cable is:** A) 500 V B) 1 kV C) 5 kV D) 10 kV Answer: D Explanation: High‑voltage cables are tested at 10 kV to ensure insulation integrity. Question 94. The primary purpose of a reactor bank in a substation is to:** A) Increase voltage B) Reduce harmonic distortion C) Limit fault current and control voltage rise D) Provide grounding Answer: C Explanation: Reactors add inductive reactance to limit fault currents and manage voltage. Question 95. The correct polarity when paralleling two three‑phase transformers is determined by:**
