CFESA Certification Exam 2026/2027 | Complete Practice Questions, Correct Answers & Detailed Rationales | Electrical, Gas, Steam & Refrigeration

CFESA Certification Exam 2026/2027 | Complete Practice Questions,
Correct Answers & Detailed Rationales | Electrical, Gas, Steam &
Refrigeration


SECTION I — ELECTRICAL
Questions 1–70
1. What is the basic unit of electrical resistance?
A. Volt
B. Ampere
C. Ohm
D. Watt
Correct Answer: C. Ohm
Rationale: The ohm (Ω) is the standard unit used to measure electrical resistance.
2. Which instrument is normally used to measure voltage?
A. Ammeter
B. Voltmeter
C. Megohmmeter only
D. Frequency counter
Correct Answer: B. Voltmeter
Rationale: A voltmeter measures electrical potential difference between two
points.
3. According to Ohm's law, voltage equals:
A. Current × resistance
B. Current ÷ resistance
C. Resistance ÷ current
D. Power × resistance

,Correct Answer: A. Current × resistance
Rationale: Ohm's law is V = I × R.
4. A 120-V circuit has a resistance of 20 Ω. What current flows?
A. 2 A
B. 4 A
C. 6 A
D. 10 A
Correct Answer: C. 6 A
Rationale: I = V/R = 120/20 = 6 A.
5. What is the primary purpose of a fuse?
A. Increase voltage
B. Protect against excessive current
C. Increase resistance
D. Improve grounding
Correct Answer: B. Protect against excessive current
Rationale: A fuse opens the circuit when current exceeds its rated value.
6. A circuit breaker that repeatedly trips may indicate:
A. Proper operation only
B. An overload or fault
C. Low resistance in every case
D. Excessive insulation
Correct Answer: B. An overload or fault
Rationale: Repeated tripping commonly indicates an overload, short circuit,
ground fault, or defective component.
7. In a series circuit, current is:
A. Different through every component
B. The same through each component

,C. Always zero
D. Greater after each resistor
Correct Answer: B. The same through each component
Rationale: A series circuit provides one current path.
8. In a parallel circuit, voltage across properly connected branches is:
A. The same
B. Always zero
C. Different by definition
D. Equal to current
Correct Answer: A. The same
Rationale: Parallel branches are connected across the same two electrical nodes.
9. What happens to total resistance when resistors are added in series?
A. It decreases
B. It increases
C. It becomes zero
D. It becomes negative
Correct Answer: B. It increases
Rationale: Series resistance is the sum of the individual resistances.
10. What happens to total resistance when another resistor is added in parallel?
A. It normally decreases
B. It always increases
C. It becomes infinite
D. It cannot change
Correct Answer: A. It normally decreases
Rationale: Adding a parallel current path lowers total circuit resistance.
11. What does AC stand for?
A. Applied current
B. Alternating current

, C. Automatic control
D. Ampere circuit
Correct Answer: B. Alternating current
Rationale: Alternating current periodically changes direction.
12. What does DC stand for?
A. Direct current
B. Dual circuit
C. Digital control
D. Dynamic current
Correct Answer: A. Direct current
Rationale: Direct current flows in one direction.
13. Electrical power is measured in:
A. Ohms
B. Watts
C. Volts
D. Hertz
Correct Answer: B. Watts
Rationale: The watt is the SI unit of electrical power.
14. A 120-V appliance draws 5 A. Approximately how much power does it
consume?
A. 24 W
B. 125 W
C. 600 W
D. 1,200 W
Correct Answer: C. 600 W
Rationale: P = V × I = 120 × 5 = 600 W.
15. What is the purpose of a grounding conductor?