LADWP Electrical Craft Helper
Ultimate Exam Prep Complete Exam
Question Bank with Verified Answers
& Detailed Rationales Latest 2026/2027
LADWP Electrical Craft Helper Ultimate Exam Prep |
Comprehensive Examination
LADWP Electrical Craft Helper Ultimate Exam Prep
Complete Exam Question Bank with Verified Answers &
Detailed Rationales Latest 2026/2027 Edition - Los Angeles
INTRODUCTION
This document is an important and very helpful preparation
resource for LADWP Electrical Craft Helper Ultimate Exam
Prep Complete Exam Question Bank with Verified Answers &
Detailed Rationales Latest 2026/2027 Edition - Los Angeles
Department of Water and Power Already Graded A+. Every
item uses a focused exam stem, four response options, a keyed
response, and a clear rationale, making it easier to understand
the subject, spot distractors, and build real exam confidence.
Page 1
, Question 1
A 3-phase, 4-wire, 480V system serves a balanced wye-connected load with
each phase impedance of 1030° . What is the magnitude of the line current?
A. 27.7 A
B. 48.0 A
C. 16.0 A
D. 83.1 A
Correct Answer: A - 27.7 A
RATIONALE
In a wye connection, phase voltage = 480/3 277 V. Phase current =
277/10 = 27.7 A, and line current equals phase current in a wye.
Options B, C, and D result from misapplying 3 or using line voltage
directly.
Question 2
Which NFPA 70E arc flash boundary calculation uses the incident energy
method for a 480V panel with a bolted fault current of 25 kA and a clearing
time of 0.1 s?
A. Arc flash boundary = 2.5 × incident energy
B. Arc flash boundary = 4.184 × incident energy
C. Arc flash boundary = 1.2 × incident energy
D. Arc flash boundary = 0.5 × incident energy
Correct Answer: B - Arc flash boundary = 4.184 × incident
energy
RATIONALE
NFPA 70E provides the arc flash boundary formula: D = 4.184 × E
(where E is incident energy in cal/cm²). The other multipliers are
incorrect and not found in the standard.
Page 2
, Question 3
A single-phase transformer is rated 50 kVA, 7200/240 V. What is the full-load
secondary current?
A. 208.3 A
B. 125.0 A
C. 416.7 A
D. 62.5 A
Correct Answer: A - 208.3 A
RATIONALE
Full-load secondary current = kVA × 1000 / V_secondary = 50,000 /
240 208.3 A. Options B, C, and D result from using primary voltage,
doubling, or halving incorrectly.
Question 4
When performing lockout/tagout on a 12 kV switchgear, which sequence
correctly follows OSHA 1910.147?
A. Notify affected employees, isolate energy, apply locks/tags, verify
zero energy, release stored energy
B. Apply locks/tags, isolate energy, verify zero energy, notify employees,
release stored energy
C. Isolate energy, apply locks/tags, release stored energy, verify zero
energy, notify employees
D. Verify zero energy, isolate energy, apply locks/tags, notify employees,
release stored energy
Correct Answer: A - Notify affected employees, isolate energy,
apply locks/tags, verify zero energy, release stored energy
Page 3
, RATIONALE
OSHA 1910.147 requires notification, isolation, lock/tag application,
release of stored energy, and verification of zero energy state in that
order. Other sequences violate the standard and create hazardous
conditions.
Question 5
A 100 HP, 460V, 3-phase induction motor has a nameplate full-load current of
124 A. What is the minimum ampacity of the branch-circuit conductors per
NEC 430.22?
A. 124 A
B. 155 A
C. 186 A
D. 248 A
Correct Answer: B - 155 A
RATIONALE
NEC 430.22 requires branch-circuit conductors to be sized at 125% of
motor full-load current: 124 × 1.25 = 155 A. The other options are
either the FLC or incorrect multipliers.
Question 6
Which test instrument is most appropriate for verifying the absence of voltage
on a de-energized 4.16 kV feeder before applying grounds?
A. Non-contact voltage tester
B. Digital multimeter rated CAT III 1000V
C. High-voltage phasing stick
D. Clamp-on ammeter
Correct Answer: C - High-voltage phasing stick
Page 4
Ultimate Exam Prep Complete Exam
Question Bank with Verified Answers
& Detailed Rationales Latest 2026/2027
LADWP Electrical Craft Helper Ultimate Exam Prep |
Comprehensive Examination
LADWP Electrical Craft Helper Ultimate Exam Prep
Complete Exam Question Bank with Verified Answers &
Detailed Rationales Latest 2026/2027 Edition - Los Angeles
INTRODUCTION
This document is an important and very helpful preparation
resource for LADWP Electrical Craft Helper Ultimate Exam
Prep Complete Exam Question Bank with Verified Answers &
Detailed Rationales Latest 2026/2027 Edition - Los Angeles
Department of Water and Power Already Graded A+. Every
item uses a focused exam stem, four response options, a keyed
response, and a clear rationale, making it easier to understand
the subject, spot distractors, and build real exam confidence.
Page 1
, Question 1
A 3-phase, 4-wire, 480V system serves a balanced wye-connected load with
each phase impedance of 1030° . What is the magnitude of the line current?
A. 27.7 A
B. 48.0 A
C. 16.0 A
D. 83.1 A
Correct Answer: A - 27.7 A
RATIONALE
In a wye connection, phase voltage = 480/3 277 V. Phase current =
277/10 = 27.7 A, and line current equals phase current in a wye.
Options B, C, and D result from misapplying 3 or using line voltage
directly.
Question 2
Which NFPA 70E arc flash boundary calculation uses the incident energy
method for a 480V panel with a bolted fault current of 25 kA and a clearing
time of 0.1 s?
A. Arc flash boundary = 2.5 × incident energy
B. Arc flash boundary = 4.184 × incident energy
C. Arc flash boundary = 1.2 × incident energy
D. Arc flash boundary = 0.5 × incident energy
Correct Answer: B - Arc flash boundary = 4.184 × incident
energy
RATIONALE
NFPA 70E provides the arc flash boundary formula: D = 4.184 × E
(where E is incident energy in cal/cm²). The other multipliers are
incorrect and not found in the standard.
Page 2
, Question 3
A single-phase transformer is rated 50 kVA, 7200/240 V. What is the full-load
secondary current?
A. 208.3 A
B. 125.0 A
C. 416.7 A
D. 62.5 A
Correct Answer: A - 208.3 A
RATIONALE
Full-load secondary current = kVA × 1000 / V_secondary = 50,000 /
240 208.3 A. Options B, C, and D result from using primary voltage,
doubling, or halving incorrectly.
Question 4
When performing lockout/tagout on a 12 kV switchgear, which sequence
correctly follows OSHA 1910.147?
A. Notify affected employees, isolate energy, apply locks/tags, verify
zero energy, release stored energy
B. Apply locks/tags, isolate energy, verify zero energy, notify employees,
release stored energy
C. Isolate energy, apply locks/tags, release stored energy, verify zero
energy, notify employees
D. Verify zero energy, isolate energy, apply locks/tags, notify employees,
release stored energy
Correct Answer: A - Notify affected employees, isolate energy,
apply locks/tags, verify zero energy, release stored energy
Page 3
, RATIONALE
OSHA 1910.147 requires notification, isolation, lock/tag application,
release of stored energy, and verification of zero energy state in that
order. Other sequences violate the standard and create hazardous
conditions.
Question 5
A 100 HP, 460V, 3-phase induction motor has a nameplate full-load current of
124 A. What is the minimum ampacity of the branch-circuit conductors per
NEC 430.22?
A. 124 A
B. 155 A
C. 186 A
D. 248 A
Correct Answer: B - 155 A
RATIONALE
NEC 430.22 requires branch-circuit conductors to be sized at 125% of
motor full-load current: 124 × 1.25 = 155 A. The other options are
either the FLC or incorrect multipliers.
Question 6
Which test instrument is most appropriate for verifying the absence of voltage
on a de-energized 4.16 kV feeder before applying grounds?
A. Non-contact voltage tester
B. Digital multimeter rated CAT III 1000V
C. High-voltage phasing stick
D. Clamp-on ammeter
Correct Answer: C - High-voltage phasing stick
Page 4
