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Question 1. Which of the following equations correctly represents Ohm’s Law? A) P = VI B) V = IR C) I = V² / R D) R = V / I² Answer: B Explanation: Ohm’s Law states that voltage (V) equals current (I) multiplied by resistance (R), i.e., V = IR. Question 2. A 120 V, 10 A load has a resistance of: A) 12 Ω B) 1.2 Ω C) 120 Ω D) 0.12 Ω Answer: A Explanation: Using R = V / I, 120 V ÷ 10 A = 12 Ω. Question 3. In a series circuit with three resistors of 4 Ω, 6 Ω, and 10 Ω, the total resistance is: A) 20 Ω B) 10 Ω C) 4 Ω D) 6 Ω Answer: A Explanation: Series resistances add directly: 4 Ω + 6 Ω + 10 Ω = 20 Ω.
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Question 4. In a parallel circuit, the total current is: A) The sum of the branch currents B) The same as the current in each branch C) Less than the smallest branch current D) Equal to the voltage divided by the total resistance Answer: A Explanation: In parallel, each branch carries its own current, and the total current is the algebraic sum of those branch currents. Question 5. The inductive reactance (X_L) of a 50 Hz coil with an inductance of 0.2 H is: A) 62.8 Ω B) 31.4 Ω C) 15.7 Ω D) 125.6 Ω Answer: A Explanation: X_L = 2πfL = 2π(50)(0.2) ≈ 62.8 Ω. Question 6. The capacitive reactance (X_C) of a 30 μF capacitor at 60 Hz is: A) 88.4 Ω B) 44.2 Ω C) 22.1 Ω D) 176.8 Ω Answer: A Explanation: X_C = 1/(2πfC) = 1/(2π·60·30×10⁻⁶) ≈ 88.4 Ω.
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Question 10. The turns ratio of a transformer is 10:1 (primary:secondary). If the primary voltage is 2400 V, the secondary voltage is: A) 240 V B) 24 V C) 4800 V D) 120 V Answer: A Explanation: V_S = (N_S/N_P) × V_P = (1/10) × 2400 V = 240 V. Question 11. Which component in a transformer provides a path for oil pressure relief? A) Bushing B) Tap changer C) Pressure relief valve D) Core clamp Answer: C Explanation: The pressure relief valve opens when oil temperature/pressure exceeds safe limits. Question 12. Additive polarity in transformer banking means: A) The secondary voltages are summed in phase B) The secondary voltages are subtracted out of phase C) The transformers are wired in Delta only D) The bank is used for single-phase loads only Answer: A Explanation: Additive polarity adds the secondary voltages vectorially, increasing the bank output.
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Question 13. When paralleling two identical three-phase transformers, the required phase rotation must be: A) Identical on all units B) Opposite on each unit C) Random, it does not matter D) Determined by the tap changer only Answer: A Explanation: All transformers must have the same phase sequence to avoid circulating currents. Question 14. The nameplate of a transformer shows “KVA = 250, V = 13.8/4.16 kV, %Z = 5”. The impedance voltage (V_Z) at full load is: A) 5 % of 13.8 kV B) 5 % of 4.16 kV C) 250 kVA × 5 % D) 13.8 kV × 5 % = 690 V Answer: D Explanation: %Z is expressed as a percent of the rated primary voltage; 5 % × 13.8 kV = 690 V. Question 15. A crossarm made of wood is classified as Class C. The typical service class rating for this crossarm is: A) 69 kV B) 138 kV C) 230 kV D) 500 kV
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D) Specified by the splice manufacturer, typically 12–15 kN Answer: D Explanation: Compression force values are set by the splice design; most aluminum compression splices require about 12–15 kN. Question 19. A guy wire with a lead-to-height ratio of 1:5 is installed on a pole that is 30 ft tall. The required lead length is: A) 6 ft B) 30 ft C) 150 ft D) 5 ft Answer: A Explanation: Lead = Height / Ratio = 30 ft / 5 = 6 ft. Question 20. The primary purpose of a vibration damper on a pole-mounted transformer is to: A) Reduce audible noise only B) Prevent oil leakage C) Minimize mechanical fatigue from wind-induced motion D) Increase transformer efficiency Answer: C Explanation: Vibration dampers absorb dynamic loads, reducing fatigue on the transformer tank and mounting hardware. Question 21. In underground residential distribution (URD), a cable with a concentric neutral typically has: A) A single central conductor only B) A neutral conductor wrapped around the inner conductor
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C) A separate neutral wire in a separate conduit D) No neutral conductor at all Answer: B Explanation: Concentric neutral cables place the neutral conductor in a helical wrap around the phase conductors. Question 22. The stress cone used on a URD cable termination serves to: A) Increase the cable diameter for easier pulling B) Reduce electric field intensity at the termination point C) Provide mechanical reinforcement only D) Seal the cable against water ingress only Answer: B Explanation: A stress cone redistributes the electric field, preventing premature breakdown at the termination. Question 23. A pad-mounted transformer rated 25 kVA, 120/240 V is installed with a 12 ft stand-off. The minimum required clearance to the nearest building per NESC is: A) 3 ft B) 6 ft C) 10 ft D) 12 ft Answer: C Explanation: NESC requires a minimum of 10 ft clearance for pad-mounted equipment of this rating. Question 24. To locate a fault in a buried cable using a thumper, the technician should:
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Question 27. The air-testing interval for rubber gloves used on live-line work is: A) Every 6 months B) Every 12 months C) Every 24 months D) Only when damage is suspected Answer: B Explanation: OSHA requires dielectric testing of rubber insulating equipment at least annually. Question 28. When rigging a load with a single sling at a 45° angle, the effective Working Load Limit (WLL) is: A) 100 % of the sling rating B) 71 % of the sling rating C) 50 % of the sling rating D) 85 % of the sling rating Answer: B Explanation: WLL = Sling rating × sin 45° ≈ 0.707 × rating. Question 29. The bowline knot is primarily used because it: A) Is easy to untie after loading B) Provides the strongest possible hold C) Is the fastest knot to tie D) Requires no training to use Answer: A Explanation: The bowline forms a secure loop that does not jam, making it easy to untie after a load is removed.
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Question 30. In grounding, an “Equipotential Zone” (EPZ) is defined as: A) A zone where all conductive parts are at the same potential B) A zone where voltage is always zero C) A zone that only applies to sub-stations D) A zone limited to 10 ft radius from the ground rod Answer: A Explanation: EPZ ensures that any person standing within it is at the same electrical potential, reducing shock risk. Question 31. A hot-stick used for live-line work must be inspected for: A) Cracks, dents, and proper length B) Color only C) Manufacturer’s logo presence D) Weight only Answer: A Explanation: Physical damage can compromise dielectric strength; therefore, hot-sticks are inspected for cracks, dents, and length compliance. Question 32. A self-contained electric meter is typically rated for a maximum primary voltage of: A) 120 V B) 240 V C) 600 V D) 1000 V Answer: C
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Answer: B Explanation: Capacitor banks supply leading VARs, correcting lagging power factor caused by inductive loads. Question 36. In a recloser, the “trip” function is triggered when: A) Voltage exceeds 1.2 × rated value B) Current exceeds the instantaneous pickup setting C) The line temperature reaches 100 °C D) The recloser reaches its scheduled maintenance interval Answer: B Explanation: Reclosers trip when measured current exceeds the set instantaneous or time-over-current thresholds. Question 37. A photocell used for street-lighting control typically operates by: A) Measuring ambient light intensity and closing the circuit when it falls below a set level B) Detecting motion of pedestrians C) Sensing temperature changes D) Monitoring line voltage fluctuations Answer: A Explanation: Photocells sense ambient illumination; when it drops below a threshold (e.g., dusk), they close the circuit to turn lights on. Question 38. The standard unit drawing for a utility is used to: A) Provide a detailed visual reference for pole-line construction, hardware, and clearances B) Show only the electrical schematic of a substation
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C) List only the material purchase order numbers D) Replace all field inspection procedures Answer: A Explanation: Standard unit drawings contain specifications for pole height, hardware placement, clearances, and construction details. Question 39. In a one-line diagram, the symbol “∏” most commonly represents: A) A transformer B) A circuit breaker C) A capacitor bank D) A recloser Answer: A Explanation: The “∏” symbol is the standard representation for a transformer in single-line diagrams. Question 40. The National Electrical Safety Code (NESC) clearance for a 69 kV line over a public road is at least: A) 12 ft B) 18 ft C) 24 ft D) 30 ft Answer: C Explanation: NESC Table 9-1 specifies a minimum of 24 ft clearance for 69 kV lines over public roadways. Question 41. The “Big Three” math for linemen includes Ohm’s Law, transformer ratios, and which third calculation?
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Question 44. The primary purpose of a pressure relief valve on a transformer is to: A) Prevent over-voltage on the secondary side B) Release oil vapor pressure when temperature rises excessively C) Provide a path for fault current D) Ground the transformer core Answer: B Explanation: When oil temperature exceeds design limits, vapor pressure builds; the valve releases it to avoid explosion. Question 45. In a three-phase open-delta transformer bank, the voltage ratio between primary and secondary is: A) 1: B) 1:√ C) √3: D) 2: Answer: B Explanation: An open-delta (V-type) provides a voltage ratio of 1:√ 3 compared to a full-delta. Question 46. The term “dead-end” in overhead line construction refers to: A) The last pole in a line where the conductor is terminated B) A pole with no hardware attached C) A pole used only for grounding D) A pole located at a substation entrance Answer: A
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Explanation: A dead-end pole is the terminal point of a conductor string, requiring a dead-end hardware assembly. Question 47. A “suspension insulator string” for a 138 kV line typically consists of how many individual insulator units? A) 1–2 units B) 3–5 units C) 6–9 units D) 10–12 units Answer: C Explanation: Higher voltages require longer strings; 138 kV commonly uses 6–9 units per string. Question 48. The most common method for splicing aluminum conductors in the field is: A) Soldered splice B) Mechanical compression splice C) Twist-on splice D) Crimp splice with copper lugs Answer: B Explanation: Mechanical compression splices are preferred for aluminum due to superior mechanical strength and low resistance. Question 49. The “lead-to-height” ratio for a guy wire is important because: A) It determines the angle of the wire, affecting tension and stability B) It sets the electrical clearance from the ground C) It defines the length of the conductor to be installed
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B) √3 × Phase voltage C) Phase voltage ÷ √ D) Zero Answer: A Explanation: In Delta, line voltage = phase voltage. Question 53. The purpose of a “tap changer” on a distribution transformer is to: A) Adjust the voltage ratio to regulate secondary voltage under load variations B) Change the transformer’s frequency rating C) Provide a grounding path D) Increase the transformer’s rating without changing the core Answer: A Explanation: Tap changers modify the number of turns on one winding, allowing voltage regulation. Question 54. A 12-kV underground cable is installed in a duct bank with a minimum separation of 12 in. from other utilities. This separation is required to: A) Prevent electromagnetic interference B) Allow space for future upgrades only C) Meet fire-code requirements only D) Facilitate cable pulling only Answer: A Explanation: Adequate spacing reduces electromagnetic coupling and induced heating between adjacent cables.
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Question 55. The term “stress cone” on a URD cable termination is most closely related to: A) Mechanical reinforcement of the cable jacket B) Electrical field grading to reduce corona and breakdown C) Providing a waterproof seal only D) Adding weight for easier burial Answer: B Explanation: Stress cones shape the electric field at the termination, preventing high-field stress. Question 56. When a pad-mounted transformer is installed on a concrete pad, the required stand-off distance is primarily to: A) Allow for thermal expansion of the transformer B) Provide clearance for maintenance access and fire protection C) Prevent the transformer from sinking into the ground D) Ensure proper grounding resistance Answer: B Explanation: Stand-off distances ensure safe access, fire separation, and compliance with clearance tables. Question 57. A “thumper” used for fault location in buried conductors creates a fault by: A) Applying a high-current, low-duration pulse that produces an audible “pop” at the fault point B) Sending a low-frequency tone that is heard through the ground C) Heating the cable until it melts D) Using a magnetic field to attract the fault point Answer: A
