Texas Journeyman Electrician Certification Exam
Prep 2026 – Practice Questions, Answers &
Detailed Rationales
1. What is the primary purpose of grounding in an electrical
system?
A. Increase circuit resistance
B. Provide a return path for normal current
C. Protect personnel by directing fault current safely to earth
D. Reduce voltage drop
Rationale: Grounding ensures that fault current has a low-resistance
path to earth, reducing shock hazards and enabling protective
devices to operate quickly.
2. What is Ohm’s Law?
A. P = IV
B. V = IR
C. I = PR
D. V = I/R²
Rationale: Ohm’s Law defines the relationship between voltage,
current, and resistance as V = IR.
3. Which device protects against ground-fault current?
A. Circuit breaker
B. Fuse
,C. Transformer
D. GFCI
Rationale: A Ground Fault Circuit Interrupter (GFCI) detects imbalance
between hot and neutral conductors.
4. What is the standard color for equipment grounding conductors?
A. White
B. Red
C. Black
D. Green or bare copper
Rationale: NEC requires grounding conductors to be green,
green/yellow, or bare copper.
5. What is voltage drop primarily affected by?
A. Power factor
B. Conductor length and load current
C. Frequency
D. Insulation type
Rationale: Voltage drop increases with longer conductors and higher
current.
6. What does a circuit breaker protect against?
A. Overvoltage only
B. Undervoltage only
C. Overcurrent conditions
D. Power factor issues
Rationale: Circuit breakers interrupt current flow when excessive
current is detected.
, 7. The formula for electrical power is:
A. V = IR
B. P = VI
C. P = I/R
D. P = V/I
Rationale: Electrical power equals voltage multiplied by current.
8. What is the function of a transformer?
A. Store electrical energy
B. Convert AC to DC
C. Step voltage up or down using electromagnetic induction
D. Limit current flow
Rationale: Transformers transfer energy between circuits through
magnetic fields.
9. Which material is commonly used for electrical conductors?
A. Rubber
B. Plastic
C. Glass
D. Copper
Rationale: Copper has high conductivity and is widely used in wiring.
10. What does NEC stand for?
A. National Energy Code
B. National Electrical Code
Prep 2026 – Practice Questions, Answers &
Detailed Rationales
1. What is the primary purpose of grounding in an electrical
system?
A. Increase circuit resistance
B. Provide a return path for normal current
C. Protect personnel by directing fault current safely to earth
D. Reduce voltage drop
Rationale: Grounding ensures that fault current has a low-resistance
path to earth, reducing shock hazards and enabling protective
devices to operate quickly.
2. What is Ohm’s Law?
A. P = IV
B. V = IR
C. I = PR
D. V = I/R²
Rationale: Ohm’s Law defines the relationship between voltage,
current, and resistance as V = IR.
3. Which device protects against ground-fault current?
A. Circuit breaker
B. Fuse
,C. Transformer
D. GFCI
Rationale: A Ground Fault Circuit Interrupter (GFCI) detects imbalance
between hot and neutral conductors.
4. What is the standard color for equipment grounding conductors?
A. White
B. Red
C. Black
D. Green or bare copper
Rationale: NEC requires grounding conductors to be green,
green/yellow, or bare copper.
5. What is voltage drop primarily affected by?
A. Power factor
B. Conductor length and load current
C. Frequency
D. Insulation type
Rationale: Voltage drop increases with longer conductors and higher
current.
6. What does a circuit breaker protect against?
A. Overvoltage only
B. Undervoltage only
C. Overcurrent conditions
D. Power factor issues
Rationale: Circuit breakers interrupt current flow when excessive
current is detected.
, 7. The formula for electrical power is:
A. V = IR
B. P = VI
C. P = I/R
D. P = V/I
Rationale: Electrical power equals voltage multiplied by current.
8. What is the function of a transformer?
A. Store electrical energy
B. Convert AC to DC
C. Step voltage up or down using electromagnetic induction
D. Limit current flow
Rationale: Transformers transfer energy between circuits through
magnetic fields.
9. Which material is commonly used for electrical conductors?
A. Rubber
B. Plastic
C. Glass
D. Copper
Rationale: Copper has high conductivity and is widely used in wiring.
10. What does NEC stand for?
A. National Energy Code
B. National Electrical Code
