Newest (2026 Update) Actual Practice
Questions – Set 100 Most Common Exam
Questions And Answers In Details 100%
Verified Exam
1. According to NEC guidelines, what is the minimum working clearance in front
of electrical equipment rated 0–600V?
A. 2 feet
B. 3 feet
C. 4 feet
D. 5 feet
✔ Correct Answer: B. [3 feet] ✔
*Rationale: The NEC requires a minimum working clearance of 3 feet in front of
electrical equipment rated up to 600 volts to ensure safe access and reduce
electrical shock risk during maintenance.
2. A circuit breaker trips repeatedly under normal load conditions. What is the
MOST likely cause?
A. Overvoltage supply
B. Undersized conductor or overload
C. Faulty grounding electrode
D. Incorrect phase rotation
,✔ Correct Answer: B. [Undersized conductor or overload] ✔
*Rationale: Repeated tripping under normal load typically indicates an overload
condition or undersized wiring causing excessive current draw.
3. What is the purpose of a Ground Fault Circuit Interrupter (GFCI)?
A. Increase circuit voltage stability
B. Prevent arc faults
C. Protect against ground-fault shock hazards
D. Reduce harmonic distortion
✔ Correct Answer: C. [Protect against ground-fault shock hazards] ✔
*Rationale: A GFCI detects imbalance between hot and neutral conductors and
quickly disconnects power to prevent electric shock.
4. In a single-phase system, the typical voltage between hot and neutral in
residential installations is:
A. 240V
B. 120V
C. 208V
D. 277V
✔ Correct Answer: B. [120V] ✔
*Rationale: Standard residential single-phase systems in the U.S. supply
approximately 120 volts between hot and neutral.
5. A conductor is rated for 20A. What is the maximum allowable continuous load
per NEC 80% rule?
A. 20A
B. 18A
C. 16A
D. 15A
,✔ Correct Answer: D. [16A] ✔
*Rationale: Continuous loads must not exceed 80% of the conductor’s rating: 20A
× 0.8 = 16A.
6. What color insulation is typically used for a grounded (neutral) conductor?
A. Green
B. White
C. Red
D. Black
✔ Correct Answer: B. [White] ✔
*Rationale: White or gray insulation is designated for grounded (neutral)
conductors per NEC standards.
7. A technician measures zero volts between hot and ground. What is the MOST
likely issue?
A. Normal condition
B. Open hot conductor
C. Reversed polarity
D. High resistance neutral
✔ Correct Answer: B. [Open hot conductor] ✔
*Rationale: Zero voltage between hot and ground indicates the hot conductor is
not energized due to an open circuit.
8. What device is used to protect against overcurrent conditions?
A. Transformer
B. Relay
C. Circuit breaker
D. Capacitor
, ✔ Correct Answer: C. [Circuit breaker] ✔
*Rationale: Circuit breakers automatically interrupt current flow during
overloads or short circuits.
9. The main purpose of equipment grounding is to:
A. Stabilize voltage
B. Carry normal load current
C. Provide a fault current path
D. Increase resistance
✔ Correct Answer: C. [Provide a fault current path] ✔
*Rationale: Grounding ensures fault current safely returns to the source to trip
protective devices.
10. Which tool is used to measure electrical resistance?
A. Ammeter
B. Voltmeter
C. Ohmmeter
D. Wattmeter
✔ Correct Answer: C. [Ohmmeter] ✔
*Rationale: An ohmmeter measures resistance in ohms within a circuit or
component.
11. A 240V circuit is typically used for:
A. Lighting only
B. Small appliances only
C. High-power appliances such as dryers
D. Low-voltage control systems