Master Electrician Licensing Exam
Practice Exam 100 Questions And
Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A Instant
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1. What is the primary purpose of a circuit breaker in an electrical circuit?
A. To increase voltage
B. To regulate frequency
C. To protect conductors from overcurrent
D. To improve power factor
A circuit breaker opens the circuit when current exceeds a safe level,
protecting conductors and connected equipment from damage caused by
overloads or short circuits.
2. Which unit is used to measure electrical resistance?
A. Volt
B. Ampere
C. Watt
D. Ohm
Resistance is measured in ohms (Ω), while voltage is measured in volts,
current in amperes, and power in watts.
3. What is the formula for Ohm's Law?
A. P = I / R
B. V = I × R
C. I = V × R
D. R = V × I
,Ohm's Law states that voltage equals current multiplied by resistance.
4. A 120-volt circuit has a resistance of 20 ohms. What current flows through
the circuit?
A. 2 A
B. 4 A
C. 6 A
D. 10 A
Using I = V / R, the current is 120 ÷ 20 = 6 amperes.
5. What is the primary purpose of an equipment grounding conductor?
A. To carry normal circuit current
B. To increase circuit voltage
C. To provide a low-impedance path for fault current
D. To reduce conductor resistance
The equipment grounding conductor provides a path for fault current that
facilitates operation of the overcurrent protective device.
6. Which conductor normally carries current back to the source in a single-
phase circuit?
A. Equipment grounding conductor
B. Grounding electrode conductor
C. Grounded (neutral) conductor
D. Bonding jumper
In a typical single-phase circuit, the grounded conductor completes the
normal current path back to the source.
7. What is the purpose of bonding metal electrical enclosures?
A. To increase circuit voltage
B. To prevent voltage production
C. To establish electrical continuity and provide a fault-current path
D. To reduce conductor ampacity
Bonding connects conductive parts together so fault current can return
effectively to the source and operate protective devices.
, 8. What happens to total resistance when two equal resistors are connected
in parallel?
A. It doubles
B. It remains unchanged
C. It becomes less than the resistance of either individual resistor
D. It becomes infinite
Parallel paths provide multiple routes for current, reducing total circuit
resistance.
9. Which formula is used to calculate electrical power in a DC circuit?
A. P = R / I
B. P = V / R
C. P = V × I
D. P = I / R
Electrical power in watts is calculated by multiplying voltage by current.
10. A 120-volt load draws 10 amperes. How much power does it consume?
A. 120 W
B. 600 W
C. 1,200 W
D. 2,400 W
P = V × I = 120 × 10 = 1,200 watts.
11. What is the main function of a transformer?
A. Convert AC to DC
B. Change AC voltage levels
C. Store electrical energy
D. Increase circuit resistance
Transformers transfer electrical energy between circuits and can step voltage
up or down through electromagnetic induction.
12. A copper conductor has an allowable ampacity of 80 A before adjustment.
If four current-carrying conductors are installed together in a raceway and the
applicable adjustment factor is 80%, what is the adjusted ampacity?
Practice Exam 100 Questions And
Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A Instant
Download Pdf
1. What is the primary purpose of a circuit breaker in an electrical circuit?
A. To increase voltage
B. To regulate frequency
C. To protect conductors from overcurrent
D. To improve power factor
A circuit breaker opens the circuit when current exceeds a safe level,
protecting conductors and connected equipment from damage caused by
overloads or short circuits.
2. Which unit is used to measure electrical resistance?
A. Volt
B. Ampere
C. Watt
D. Ohm
Resistance is measured in ohms (Ω), while voltage is measured in volts,
current in amperes, and power in watts.
3. What is the formula for Ohm's Law?
A. P = I / R
B. V = I × R
C. I = V × R
D. R = V × I
,Ohm's Law states that voltage equals current multiplied by resistance.
4. A 120-volt circuit has a resistance of 20 ohms. What current flows through
the circuit?
A. 2 A
B. 4 A
C. 6 A
D. 10 A
Using I = V / R, the current is 120 ÷ 20 = 6 amperes.
5. What is the primary purpose of an equipment grounding conductor?
A. To carry normal circuit current
B. To increase circuit voltage
C. To provide a low-impedance path for fault current
D. To reduce conductor resistance
The equipment grounding conductor provides a path for fault current that
facilitates operation of the overcurrent protective device.
6. Which conductor normally carries current back to the source in a single-
phase circuit?
A. Equipment grounding conductor
B. Grounding electrode conductor
C. Grounded (neutral) conductor
D. Bonding jumper
In a typical single-phase circuit, the grounded conductor completes the
normal current path back to the source.
7. What is the purpose of bonding metal electrical enclosures?
A. To increase circuit voltage
B. To prevent voltage production
C. To establish electrical continuity and provide a fault-current path
D. To reduce conductor ampacity
Bonding connects conductive parts together so fault current can return
effectively to the source and operate protective devices.
, 8. What happens to total resistance when two equal resistors are connected
in parallel?
A. It doubles
B. It remains unchanged
C. It becomes less than the resistance of either individual resistor
D. It becomes infinite
Parallel paths provide multiple routes for current, reducing total circuit
resistance.
9. Which formula is used to calculate electrical power in a DC circuit?
A. P = R / I
B. P = V / R
C. P = V × I
D. P = I / R
Electrical power in watts is calculated by multiplying voltage by current.
10. A 120-volt load draws 10 amperes. How much power does it consume?
A. 120 W
B. 600 W
C. 1,200 W
D. 2,400 W
P = V × I = 120 × 10 = 1,200 watts.
11. What is the main function of a transformer?
A. Convert AC to DC
B. Change AC voltage levels
C. Store electrical energy
D. Increase circuit resistance
Transformers transfer electrical energy between circuits and can step voltage
up or down through electromagnetic induction.
12. A copper conductor has an allowable ampacity of 80 A before adjustment.
If four current-carrying conductors are installed together in a raceway and the
applicable adjustment factor is 80%, what is the adjusted ampacity?
