NEW MEXICO EL 1J ELECTRICAL
DISTRIBUTION JOURNEYMAN
PRACTICE EXAM QUESTIONS WITH
CORRECT ANSWERS
1. When installing a 12.47kV distribution line, what is the minimum vertical clearance
required for conductors crossing over a road subject to truck traffic according to NESC Table
232-1?
A. 15.5 feet
B. 18.5 feet
C. 20.0 feet
D. 22.0 feet
Answer: B
Conceptual Explanation: The NESC (National Electrical Safety Code) requires a minimum
vertical clearance of 18.5 feet for voltages up to 22kV when crossing roads subject to truck
traffic.
,2. A three-phase transformer bank is connected in a Delta-Wye configuration. If the primary
line-to-line voltage is 13.8kV and the secondary is 480/277V, what is the turns ratio of each
individual transformer?
A. 28.75:1
B. 16.63:1
C. 49.82:1
D. 8.29:1
Answer: C
Conceptual Explanation: In a Delta-Wye transformer, the primary phase voltage equals
the line voltage (13,800V). The secondary phase voltage is 277V. Ratio = =
49.82.
3. According to NEC Article 250.66, what is the maximum size copper grounding electrode
conductor required for a service supplied by 1100 kcmil copper service-entrance conductors?
A. 1/0 AWG
B. 2/0 AWG
C. 250 kcmil
D. 3/0 AWG
Answer: D
, Conceptual Explanation: For service-entrance conductors over 600 kcmil through 1100
kcmil copper, Table 250.66 requires a 3/0 AWG copper grounding electrode conductor.
4. In a medium-voltage shielded cable, what is the primary purpose of the semiconductor
strand shield?
A. To eliminate air voids and equalize voltage stress at the conductor surface
B. To increase the overall ampacity of the conductor
C. To provide mechanical protection against impact
D. To act as the system neutral for return current
Answer: A
Conceptual Explanation: The semiconductor strand shield ensures a smooth surface
between the conductor and insulation, eliminating air gaps that could cause corona
discharge and insulation failure.
5. What is the minimum burial depth for a 15kV direct-buried cable in an area not subject to
vehicular traffic, assuming no concrete encasement?
A. 24 inches
B. 36 inches
C. 30 inches
D. 42 inches
Answer: C
DISTRIBUTION JOURNEYMAN
PRACTICE EXAM QUESTIONS WITH
CORRECT ANSWERS
1. When installing a 12.47kV distribution line, what is the minimum vertical clearance
required for conductors crossing over a road subject to truck traffic according to NESC Table
232-1?
A. 15.5 feet
B. 18.5 feet
C. 20.0 feet
D. 22.0 feet
Answer: B
Conceptual Explanation: The NESC (National Electrical Safety Code) requires a minimum
vertical clearance of 18.5 feet for voltages up to 22kV when crossing roads subject to truck
traffic.
,2. A three-phase transformer bank is connected in a Delta-Wye configuration. If the primary
line-to-line voltage is 13.8kV and the secondary is 480/277V, what is the turns ratio of each
individual transformer?
A. 28.75:1
B. 16.63:1
C. 49.82:1
D. 8.29:1
Answer: C
Conceptual Explanation: In a Delta-Wye transformer, the primary phase voltage equals
the line voltage (13,800V). The secondary phase voltage is 277V. Ratio = =
49.82.
3. According to NEC Article 250.66, what is the maximum size copper grounding electrode
conductor required for a service supplied by 1100 kcmil copper service-entrance conductors?
A. 1/0 AWG
B. 2/0 AWG
C. 250 kcmil
D. 3/0 AWG
Answer: D
, Conceptual Explanation: For service-entrance conductors over 600 kcmil through 1100
kcmil copper, Table 250.66 requires a 3/0 AWG copper grounding electrode conductor.
4. In a medium-voltage shielded cable, what is the primary purpose of the semiconductor
strand shield?
A. To eliminate air voids and equalize voltage stress at the conductor surface
B. To increase the overall ampacity of the conductor
C. To provide mechanical protection against impact
D. To act as the system neutral for return current
Answer: A
Conceptual Explanation: The semiconductor strand shield ensures a smooth surface
between the conductor and insulation, eliminating air gaps that could cause corona
discharge and insulation failure.
5. What is the minimum burial depth for a 15kV direct-buried cable in an area not subject to
vehicular traffic, assuming no concrete encasement?
A. 24 inches
B. 36 inches
C. 30 inches
D. 42 inches
Answer: C
