Certification Practice Exam Questions

Electrical Power Distribution Technician Certification Practice Exam Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary function of a distribution transformer?
• Convert AC to DC
• Step up voltage for transmission
• Step down voltage for consumer use
• Regulate current

Rationale: Distribution transformers reduce high transmission

voltages to levels suitable for residential or commercial use.

• Which type of conductor is most commonly used in overhead

distribution lines?

• Aluminum 1 / 4

• Aluminum Conductor Steel-Reinforced (ACSR)
• Copper-clad steel
• Pure copper

Rationale: ACSR conductors provide a good balance of strength and

conductivity for overhead lines.

• What is the standard frequency of electric power distribution in most

countries?

• 25 Hz
• 50 Hz in all countries
• 50 Hz or 60 Hz depending on the region
• 60 Hz only

Rationale: Most countries use either 50 Hz or 60 Hz depending on

regional standards.

• Which device is used to protect distribution lines from short circuits?
• Circuit breaker
• Fuse
• Step-down transformer
• Voltage regulator

Rationale: Fuses interrupt current in case of overcurrent or short

circuits, preventing damage to equipment.

• What is the purpose of a lightning arrester in a distribution system?
• Step down voltage
• Store electrical energy 2 / 4

• Protect equipment from voltage surges due to lightning
• Increase system efficiency

Rationale: Lightning arresters divert surge currents caused by

lightning to the ground, protecting equipment.

• What does the term "three-phase system" refer to?
• Single alternating current
• Three alternating currents with 120° phase difference
• Three DC circuits
• A high-voltage storage system

Rationale: Three-phase systems consist of three AC voltages

separated by 120 degrees, commonly used in power distribution.

• Which instrument is used to measure current in a live conductor?
• Voltmeter
• Ohmmeter
• Clamp meter
• Wattmeter

Rationale: Clamp meters can measure current without disconnecting

the circuit by clamping around a conductor.

• What is the typical voltage level for low-voltage distribution in urban

areas?

• 220 kV
• 33 kV

C. 230/400 V 3 / 4

• 11 kV

Rationale: Low-voltage distribution for residential and commercial

use is typically 230 V phase-to-neutral or 400 V phase-to-phase.

• Which type of grounding is commonly used for residential distribution

systems?

• Isolated neutral
• TN-S system
• IT system
• Floating system

Rationale: TN-S systems provide a separate protective earth

conductor, which is standard in residential wiring.

• What is the main disadvantage of underground distribution lines

compared to overhead lines?

• Less reliable
• More prone to lightning
• Higher installation and maintenance cost
• Limited to low voltage only

Rationale: Underground lines are less exposed to weather but

require higher initial cost and complex maintenance.

• What is the function of a circuit breaker in a distribution system?
• Step down voltage
• Interrupt overcurrent or fault conditions
• Store energy
• / 4