Wisconsin Master Electrician Industrial
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1. Under the National Electrical Code (NEC), the primary purpose of
overcurrent protection devices is to:
A. Increase the voltage available to equipment
B. Protect conductors and equipment from excessive current
C. Improve power factor in industrial systems
D. Reduce the need for grounding conductors
Answer: B. Protect conductors and equipment from excessive current
Overcurrent protection devices such as fuses and circuit breakers are
designed to interrupt excessive current caused by overloads or short
circuits, preventing conductor damage and equipment failure.
, 2. In an industrial electrical installation, the grounding electrode system
is primarily intended to:
A. Provide a low-impedance path for fault current
B. Increase motor efficiency
C. Replace equipment grounding conductors
D. Eliminate the need for bonding
Answer: A. Provide a low-impedance path for fault current
The grounding electrode system connects the electrical system to earth
and helps stabilize voltage while assisting with fault-current paths when
properly bonded with the equipment grounding system.
3. A three-phase motor operates at 480 volts and draws 50 amperes. The
approximate apparent power is:
A. 20.8 kVA
B. 41.6 kVA
C. 83.1 kVA
D. 120 kVA
Answer: B. 41.6 kVA
Three-phase apparent power is calculated using volts × amperes × 1.732.
The calculation is 480 × 50 × 1.732 = approximately 41.6 kVA.
, 4. The NEC requires industrial disconnecting means to be:
A. Located only outdoors
B. Readily accessible and capable of being locked in the open position
C. Installed only by equipment manufacturers
D. Located more than 50 feet from equipment
Answer: B. Readily accessible and capable of being locked in the open
position
Disconnecting means must allow safe servicing and maintenance by
qualified personnel and must be accessible and capable of being secured in
the open position.
5. The main function of a motor overload protective device is to protect
against:
A. Lightning surges
B. Ground faults only
C. Excessive motor current caused by overload conditions
D. Low voltage conditions only
Answer: C. Excessive motor current caused by overload conditions
Motor overload protection prevents damage from sustained overcurrent
conditions that cause excessive heating of motor windings.
, 6. Which conductor is normally used to carry unbalanced current in a
three-phase, four-wire system?
A. Equipment grounding conductor
B. Neutral conductor
C. Bonding jumper
D. Grounding electrode conductor
Answer: B. Neutral conductor
In a four-wire system, the neutral conductor carries the imbalance of
current from the ungrounded conductors supplying single-phase loads.
7. The purpose of bonding metal electrical equipment together is to:
A. Increase circuit voltage
B. Provide an effective fault-current path
C. Reduce conductor size requirements
D. Eliminate overcurrent devices
Answer: B. Provide an effective fault-current path
Bonding ensures exposed conductive parts remain at the same potential
and provides a path for fault current to operate protective devices.
8. A megohmmeter is commonly used to test:
Exam Practice Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. Under the National Electrical Code (NEC), the primary purpose of
overcurrent protection devices is to:
A. Increase the voltage available to equipment
B. Protect conductors and equipment from excessive current
C. Improve power factor in industrial systems
D. Reduce the need for grounding conductors
Answer: B. Protect conductors and equipment from excessive current
Overcurrent protection devices such as fuses and circuit breakers are
designed to interrupt excessive current caused by overloads or short
circuits, preventing conductor damage and equipment failure.
, 2. In an industrial electrical installation, the grounding electrode system
is primarily intended to:
A. Provide a low-impedance path for fault current
B. Increase motor efficiency
C. Replace equipment grounding conductors
D. Eliminate the need for bonding
Answer: A. Provide a low-impedance path for fault current
The grounding electrode system connects the electrical system to earth
and helps stabilize voltage while assisting with fault-current paths when
properly bonded with the equipment grounding system.
3. A three-phase motor operates at 480 volts and draws 50 amperes. The
approximate apparent power is:
A. 20.8 kVA
B. 41.6 kVA
C. 83.1 kVA
D. 120 kVA
Answer: B. 41.6 kVA
Three-phase apparent power is calculated using volts × amperes × 1.732.
The calculation is 480 × 50 × 1.732 = approximately 41.6 kVA.
, 4. The NEC requires industrial disconnecting means to be:
A. Located only outdoors
B. Readily accessible and capable of being locked in the open position
C. Installed only by equipment manufacturers
D. Located more than 50 feet from equipment
Answer: B. Readily accessible and capable of being locked in the open
position
Disconnecting means must allow safe servicing and maintenance by
qualified personnel and must be accessible and capable of being secured in
the open position.
5. The main function of a motor overload protective device is to protect
against:
A. Lightning surges
B. Ground faults only
C. Excessive motor current caused by overload conditions
D. Low voltage conditions only
Answer: C. Excessive motor current caused by overload conditions
Motor overload protection prevents damage from sustained overcurrent
conditions that cause excessive heating of motor windings.
, 6. Which conductor is normally used to carry unbalanced current in a
three-phase, four-wire system?
A. Equipment grounding conductor
B. Neutral conductor
C. Bonding jumper
D. Grounding electrode conductor
Answer: B. Neutral conductor
In a four-wire system, the neutral conductor carries the imbalance of
current from the ungrounded conductors supplying single-phase loads.
7. The purpose of bonding metal electrical equipment together is to:
A. Increase circuit voltage
B. Provide an effective fault-current path
C. Reduce conductor size requirements
D. Eliminate overcurrent devices
Answer: B. Provide an effective fault-current path
Bonding ensures exposed conductive parts remain at the same potential
and provides a path for fault current to operate protective devices.
8. A megohmmeter is commonly used to test:
