Tennessee (TN) CE-A, H High-Voltage Electrical Contractor
1. What voltage level is generally considered “high voltage” in electrical
contracting?
A. Above 120 volts
B. Above 240 volts
C. Above 600 volts
D. Above 1,000 volts
Correct Answer: C
Explanation:
The NEC defines high voltage as systems operating over 600 volts nominal.
2. Which NEC article primarily governs installations over 600 volts?
A. Article 110
B. Article 210
C. Article 230
D. Article 490
Correct Answer: D
Explanation:
NEC Article 490 applies specifically to equipment operating over 600 volts.
3. Which PPE is required when working on energized high-voltage
equipment?
,A. Safety glasses only
B. Arc-rated clothing
C. Leather gloves only
D. Cotton clothing
Correct Answer: B
Explanation:
High-voltage energized work requires arc-rated clothing to protect against arc
flash hazards.
4. What is the primary purpose of grounding high-voltage systems?
A. Improve voltage regulation
B. Reduce power consumption
C. Provide a safe path for fault current
D. Increase system capacity
Correct Answer: C
Explanation:
Grounding provides a low-resistance path for fault current, protecting people
and equipment.
5. Which device protects high-voltage circuits from overloads and short
circuits?
A. Relay
B. Transformer
C. Capacitor
D. Meter
Correct Answer: A
Explanation:
Protective relays detect abnormal conditions and initiate circuit interruption.
6. What is the function of a step-down transformer?
A. Increase voltage
B. Decrease voltage
,C. Regulate frequency
D. Store energy
Correct Answer: B
Explanation:
A step-down transformer reduces voltage to a safer or usable level.
7. Which grounding method is commonly used for high-voltage
substations?
A. Isolated ground
B. Ground ring
C. Single rod
D. Ungrounded
Correct Answer: B
Explanation:
A ground ring provides uniform grounding and reduces step and touch
potential.
8. What is “step potential”?
A. Voltage between phases
B. Voltage across equipment
C. Voltage difference between feet on the ground
D. Voltage in a conductor
Correct Answer: C
Explanation:
Step potential occurs when a person’s feet are at different voltages due to
ground fault current.
9. Which NEC article covers grounding and bonding?
A. Article 100
B. Article 110
C. Article 250
D. Article 300
, Correct Answer: C
Explanation:
NEC Article 250 addresses grounding and bonding requirements.
10. High-voltage work should only be performed by workers who are:
A. Apprentices
B. Licensed and qualified
C. Supervisors only
D. Inspectors
Correct Answer: B
Explanation:
Only qualified persons with proper training are permitted to work on high-
voltage systems.
11. Which conductor insulation is commonly used for underground high-
voltage cables?
A. THHN
B. NM
C. XLPE
D. UF
Correct Answer: C
Explanation:
XLPE (Cross-Linked Polyethylene) is widely used for high-voltage
underground installations.
12. What is the purpose of a lightning arrester?
A. Increase voltage
B. Reduce current
C. Protect equipment from surges
D. Balance load
Correct Answer: C
1. What voltage level is generally considered “high voltage” in electrical
contracting?
A. Above 120 volts
B. Above 240 volts
C. Above 600 volts
D. Above 1,000 volts
Correct Answer: C
Explanation:
The NEC defines high voltage as systems operating over 600 volts nominal.
2. Which NEC article primarily governs installations over 600 volts?
A. Article 110
B. Article 210
C. Article 230
D. Article 490
Correct Answer: D
Explanation:
NEC Article 490 applies specifically to equipment operating over 600 volts.
3. Which PPE is required when working on energized high-voltage
equipment?
,A. Safety glasses only
B. Arc-rated clothing
C. Leather gloves only
D. Cotton clothing
Correct Answer: B
Explanation:
High-voltage energized work requires arc-rated clothing to protect against arc
flash hazards.
4. What is the primary purpose of grounding high-voltage systems?
A. Improve voltage regulation
B. Reduce power consumption
C. Provide a safe path for fault current
D. Increase system capacity
Correct Answer: C
Explanation:
Grounding provides a low-resistance path for fault current, protecting people
and equipment.
5. Which device protects high-voltage circuits from overloads and short
circuits?
A. Relay
B. Transformer
C. Capacitor
D. Meter
Correct Answer: A
Explanation:
Protective relays detect abnormal conditions and initiate circuit interruption.
6. What is the function of a step-down transformer?
A. Increase voltage
B. Decrease voltage
,C. Regulate frequency
D. Store energy
Correct Answer: B
Explanation:
A step-down transformer reduces voltage to a safer or usable level.
7. Which grounding method is commonly used for high-voltage
substations?
A. Isolated ground
B. Ground ring
C. Single rod
D. Ungrounded
Correct Answer: B
Explanation:
A ground ring provides uniform grounding and reduces step and touch
potential.
8. What is “step potential”?
A. Voltage between phases
B. Voltage across equipment
C. Voltage difference between feet on the ground
D. Voltage in a conductor
Correct Answer: C
Explanation:
Step potential occurs when a person’s feet are at different voltages due to
ground fault current.
9. Which NEC article covers grounding and bonding?
A. Article 100
B. Article 110
C. Article 250
D. Article 300
, Correct Answer: C
Explanation:
NEC Article 250 addresses grounding and bonding requirements.
10. High-voltage work should only be performed by workers who are:
A. Apprentices
B. Licensed and qualified
C. Supervisors only
D. Inspectors
Correct Answer: B
Explanation:
Only qualified persons with proper training are permitted to work on high-
voltage systems.
11. Which conductor insulation is commonly used for underground high-
voltage cables?
A. THHN
B. NM
C. XLPE
D. UF
Correct Answer: C
Explanation:
XLPE (Cross-Linked Polyethylene) is widely used for high-voltage
underground installations.
12. What is the purpose of a lightning arrester?
A. Increase voltage
B. Reduce current
C. Protect equipment from surges
D. Balance load
Correct Answer: C
