NEW MEXICO EL-1 ELECTRICAL DISTRIBUTION &
TRANSMISSION EXAM COMPLETE EXAM QUESTIONS AND
VERIFIED ANSWERS | 2026–2027 LATEST UPDATE |
GUARANTEED PASS | DETAILED RATIONALES | FULL STUDY
GUIDE | EXAM PREP | PRACTICE TEST | CERTIFICATION
PREPARATION
Section One: Questions 1–100
1) What is the primary function of a transmission line in an electrical power system?
A) To step up voltage for industrial use
B) To transport bulk power over long distances from generation to load centers
C) To distribute power to individual homes
D) To convert AC to DC
Correct Answer: B) To transport bulk power over long distances from generation to load centers
Rationale: Transmission lines carry high-voltage bulk power from generating stations to substations
near load areas, minimizing losses over long distances. Distribution systems deliver power to end
users, while step-up transformers are used at generating stations. AC-to-DC conversion is the role of
rectifiers, not transmission lines.
2) Which voltage range is typical for high-voltage transmission in New Mexico?
A) 120–240 V
B) 4 kV – 35 kV
C) 115 kV – 345 kV
D) 500 kV – 765 kV
Correct Answer: C) 115 kV – 345 kV
Rationale: In New Mexico, transmission voltages commonly range from 115 kV to 345 kV. While
extra-high-voltage lines (500 kV and above) exist, 115–345 kV is typical for main transmission.
Options A and B represent secondary distribution and primary feeder voltages, respectively.
3) What is the most common conductor material used in overhead transmission lines?
A) Copper
B) Silver
C) Aluminum Conductor Steel Reinforced (ACSR)
D) Pure aluminum
,Correct Answer: C) Aluminum Conductor Steel Reinforced (ACSR)
Rationale: ACSR combines aluminum's conductivity with steel's tensile strength, offering a favorable
strength-to-weight ratio and lower cost than copper. Copper is heavier and more expensive, while
pure aluminum lacks mechanical strength for long spans. Silver is prohibitively expensive for
transmission lines.
4) In a distribution system, a "primary feeder" operates at which voltage?
A) 120 V
B) 240 V
C) 4 kV – 35 kV
D) 115 kV
Correct Answer: C) 4 kV – 35 kV
Rationale: Primary feeders in distribution systems typically operate between 4 kV and 35 kV, stepping
down via distribution transformers to secondary voltages (120/240 V) for customers. 115 kV is
transmission-level voltage, while 120 V and 240 V are secondary utilization voltages.
5) What is the primary purpose of a distribution substation?
A) Increase voltage for long-distance transmission
B) Step down transmission voltage to primary distribution levels
C) Convert AC to DC for industrial loads
D) Store energy for peak demand
Correct Answer: B) Step down transmission voltage to primary distribution levels
Rationale: A distribution substation receives power from the transmission system and steps it down to
sub-transmission or primary distribution levels (typically 4 kV to 34.5 kV). Option A describes a step-
up transmission substation. Energy storage and AC-to-DC conversion are not substation primary
functions.
6) What is the purpose of a recloser on a distribution feeder?
A) Step down voltage for residential service
B) Automatically open and reclose to clear temporary faults
C) Disconnect the line during maintenance
D) Measure power consumption
Correct Answer: B) Automatically open and reclose to clear temporary faults
Rationale: Reclosers clear temporary faults (such as lightning strikes or tree branch contact) by
opening and automatically reclosing after a delay. If the fault persists after a preset number of
operations, the recloser locks open. They do not step down voltage, disconnect for maintenance, or
measure consumption.
, 7) Which OSHA standard specifically governs safety for electric power generation, transmission,
and distribution?
A) 29 CFR 1910.147
B) 29 CFR 1910.269
C) 29 CFR 1926.416
D) 29 CFR 1910.212
Correct Answer: B) 29 CFR 1910.269
Rationale: OSHA 29 CFR 1910.269 covers electric power generation, transmission, and distribution
work, including grounding, approach distances, PPE, and safe practices. 1910.147 covers
lockout/tagout, 1926.416 addresses general construction electrical safety, and 1910.212 covers
machine guarding.
8) According to OSHA 1910.269, rubber insulating gloves used for high-voltage work must be
electrically tested at what interval?
A) Daily
B) Monthly
C) Every 6 months
D) Annually
Correct Answer: C) Every 6 months
Rationale: OSHA 1910.269 requires electrical testing of rubber insulating gloves every 6 months, plus
daily visual and air tests by the user. Monthly and annual testing are not the specified OSHA intervals.
Daily testing is for visual inspection, not electrical testing.
9) What is the primary purpose of step and touch potential mitigation in substations?
A) Reduce equipment noise
B) Protect personnel from dangerous voltage gradients during faults
C) Improve power factor
D) Increase transformer efficiency
Correct Answer: B) Protect personnel from dangerous voltage gradients during faults
Rationale: Ground grids and surface materials (such as gravel) limit step and touch voltages,
protecting workers from lethal gradients during ground faults. This safety measure does not reduce
noise, improve power factor, or increase transformer efficiency.
10) What is the purpose of temporary protective grounding in distribution line work?
A) Improve power factor
B) Create an equipotential zone and prevent shock from induced voltage
C) Increase line voltage for testing
D) Reduce sag in conductors
TRANSMISSION EXAM COMPLETE EXAM QUESTIONS AND
VERIFIED ANSWERS | 2026–2027 LATEST UPDATE |
GUARANTEED PASS | DETAILED RATIONALES | FULL STUDY
GUIDE | EXAM PREP | PRACTICE TEST | CERTIFICATION
PREPARATION
Section One: Questions 1–100
1) What is the primary function of a transmission line in an electrical power system?
A) To step up voltage for industrial use
B) To transport bulk power over long distances from generation to load centers
C) To distribute power to individual homes
D) To convert AC to DC
Correct Answer: B) To transport bulk power over long distances from generation to load centers
Rationale: Transmission lines carry high-voltage bulk power from generating stations to substations
near load areas, minimizing losses over long distances. Distribution systems deliver power to end
users, while step-up transformers are used at generating stations. AC-to-DC conversion is the role of
rectifiers, not transmission lines.
2) Which voltage range is typical for high-voltage transmission in New Mexico?
A) 120–240 V
B) 4 kV – 35 kV
C) 115 kV – 345 kV
D) 500 kV – 765 kV
Correct Answer: C) 115 kV – 345 kV
Rationale: In New Mexico, transmission voltages commonly range from 115 kV to 345 kV. While
extra-high-voltage lines (500 kV and above) exist, 115–345 kV is typical for main transmission.
Options A and B represent secondary distribution and primary feeder voltages, respectively.
3) What is the most common conductor material used in overhead transmission lines?
A) Copper
B) Silver
C) Aluminum Conductor Steel Reinforced (ACSR)
D) Pure aluminum
,Correct Answer: C) Aluminum Conductor Steel Reinforced (ACSR)
Rationale: ACSR combines aluminum's conductivity with steel's tensile strength, offering a favorable
strength-to-weight ratio and lower cost than copper. Copper is heavier and more expensive, while
pure aluminum lacks mechanical strength for long spans. Silver is prohibitively expensive for
transmission lines.
4) In a distribution system, a "primary feeder" operates at which voltage?
A) 120 V
B) 240 V
C) 4 kV – 35 kV
D) 115 kV
Correct Answer: C) 4 kV – 35 kV
Rationale: Primary feeders in distribution systems typically operate between 4 kV and 35 kV, stepping
down via distribution transformers to secondary voltages (120/240 V) for customers. 115 kV is
transmission-level voltage, while 120 V and 240 V are secondary utilization voltages.
5) What is the primary purpose of a distribution substation?
A) Increase voltage for long-distance transmission
B) Step down transmission voltage to primary distribution levels
C) Convert AC to DC for industrial loads
D) Store energy for peak demand
Correct Answer: B) Step down transmission voltage to primary distribution levels
Rationale: A distribution substation receives power from the transmission system and steps it down to
sub-transmission or primary distribution levels (typically 4 kV to 34.5 kV). Option A describes a step-
up transmission substation. Energy storage and AC-to-DC conversion are not substation primary
functions.
6) What is the purpose of a recloser on a distribution feeder?
A) Step down voltage for residential service
B) Automatically open and reclose to clear temporary faults
C) Disconnect the line during maintenance
D) Measure power consumption
Correct Answer: B) Automatically open and reclose to clear temporary faults
Rationale: Reclosers clear temporary faults (such as lightning strikes or tree branch contact) by
opening and automatically reclosing after a delay. If the fault persists after a preset number of
operations, the recloser locks open. They do not step down voltage, disconnect for maintenance, or
measure consumption.
, 7) Which OSHA standard specifically governs safety for electric power generation, transmission,
and distribution?
A) 29 CFR 1910.147
B) 29 CFR 1910.269
C) 29 CFR 1926.416
D) 29 CFR 1910.212
Correct Answer: B) 29 CFR 1910.269
Rationale: OSHA 29 CFR 1910.269 covers electric power generation, transmission, and distribution
work, including grounding, approach distances, PPE, and safe practices. 1910.147 covers
lockout/tagout, 1926.416 addresses general construction electrical safety, and 1910.212 covers
machine guarding.
8) According to OSHA 1910.269, rubber insulating gloves used for high-voltage work must be
electrically tested at what interval?
A) Daily
B) Monthly
C) Every 6 months
D) Annually
Correct Answer: C) Every 6 months
Rationale: OSHA 1910.269 requires electrical testing of rubber insulating gloves every 6 months, plus
daily visual and air tests by the user. Monthly and annual testing are not the specified OSHA intervals.
Daily testing is for visual inspection, not electrical testing.
9) What is the primary purpose of step and touch potential mitigation in substations?
A) Reduce equipment noise
B) Protect personnel from dangerous voltage gradients during faults
C) Improve power factor
D) Increase transformer efficiency
Correct Answer: B) Protect personnel from dangerous voltage gradients during faults
Rationale: Ground grids and surface materials (such as gravel) limit step and touch voltages,
protecting workers from lethal gradients during ground faults. This safety measure does not reduce
noise, improve power factor, or increase transformer efficiency.
10) What is the purpose of temporary protective grounding in distribution line work?
A) Improve power factor
B) Create an equipotential zone and prevent shock from induced voltage
C) Increase line voltage for testing
D) Reduce sag in conductors
