NCBEEC – Intermediate Electrical Contractor
Examination Questions and Correct Answers
(Verified Answers) Plus Rationale 2027 Q&A|
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1. Under the NEC, what is the primary purpose of an overcurrent
protective device?
A. To increase circuit voltage
B. To improve power factor
C. To protect conductors and equipment from excessive current
D. To provide a grounding electrode
Answer: C. To protect conductors and equipment from excessive
current
Rationale: Overcurrent protective devices such as circuit breakers and
fuses are designed to open a circuit when current exceeds the allowable
level. This protects conductors and connected equipment from damage
caused by overloads and short circuits.
, 2. What is the minimum copper conductor size generally permitted
for a 20-ampere branch circuit under the NEC?
A. 14 AWG
B. 12 AWG
C. 10 AWG
D. 8 AWG
Answer: B. 12 AWG
Rationale: A standard 20-ampere branch circuit is generally supplied
with 12 AWG copper conductors. Although conductor ampacity can be
affected by several factors, 12 AWG copper is the typical minimum
conductor size for a 20-ampere circuit.
3. Which conductor is normally identified by a continuous white or
gray insulation color?
A. Ungrounded conductor
B. Grounding electrode conductor
C. Grounded conductor
D. Equipment grounding conductor only
Answer: C. Grounded conductor
,Rationale: The grounded conductor, commonly called the neutral
conductor, is normally identified by white or gray insulation or
markings. This identification helps electricians distinguish it from
ungrounded conductors.
4. What is the main function of an equipment grounding conductor?
A. Carry normal circuit current
B. Provide a low-impedance path for fault current
C. Increase the circuit's voltage
D. Balance the utility transformer
Answer: B. Provide a low-impedance path for fault current
Rationale: The equipment grounding conductor provides a conductive
path intended to carry fault current back to the source so that the
overcurrent protective device can operate promptly and disconnect the
faulted circuit.
5. A 120-volt load draws 10 amperes. What is the approximate
power consumed by the load?
A. 12 watts
B. 120 watts
, C. 1,200 watts
D. 12,000 watts
Answer: C. 1,200 watts
Rationale: Using the basic power relationship P = E × I, the load
consumes 120 volts × 10 amperes = 1,200 watts.
6. What is the purpose of a grounding electrode system?
A. To provide a path for normal load current
B. To establish a connection to earth for the electrical system
C. To replace all circuit breakers
D. To increase conductor ampacity
Answer: B. To establish a connection to earth for the electrical system
Rationale: A grounding electrode system connects the electrical system
to earth. It helps stabilize voltage to earth and provides a reference for
the electrical system, while system and equipment grounding
conductors perform different fault-current functions.
7. Which device is specifically intended to provide protection against
ground-fault shock hazards to people?
Examination Questions and Correct Answers
(Verified Answers) Plus Rationale 2027 Q&A|
Instant Download Pdf
1. Under the NEC, what is the primary purpose of an overcurrent
protective device?
A. To increase circuit voltage
B. To improve power factor
C. To protect conductors and equipment from excessive current
D. To provide a grounding electrode
Answer: C. To protect conductors and equipment from excessive
current
Rationale: Overcurrent protective devices such as circuit breakers and
fuses are designed to open a circuit when current exceeds the allowable
level. This protects conductors and connected equipment from damage
caused by overloads and short circuits.
, 2. What is the minimum copper conductor size generally permitted
for a 20-ampere branch circuit under the NEC?
A. 14 AWG
B. 12 AWG
C. 10 AWG
D. 8 AWG
Answer: B. 12 AWG
Rationale: A standard 20-ampere branch circuit is generally supplied
with 12 AWG copper conductors. Although conductor ampacity can be
affected by several factors, 12 AWG copper is the typical minimum
conductor size for a 20-ampere circuit.
3. Which conductor is normally identified by a continuous white or
gray insulation color?
A. Ungrounded conductor
B. Grounding electrode conductor
C. Grounded conductor
D. Equipment grounding conductor only
Answer: C. Grounded conductor
,Rationale: The grounded conductor, commonly called the neutral
conductor, is normally identified by white or gray insulation or
markings. This identification helps electricians distinguish it from
ungrounded conductors.
4. What is the main function of an equipment grounding conductor?
A. Carry normal circuit current
B. Provide a low-impedance path for fault current
C. Increase the circuit's voltage
D. Balance the utility transformer
Answer: B. Provide a low-impedance path for fault current
Rationale: The equipment grounding conductor provides a conductive
path intended to carry fault current back to the source so that the
overcurrent protective device can operate promptly and disconnect the
faulted circuit.
5. A 120-volt load draws 10 amperes. What is the approximate
power consumed by the load?
A. 12 watts
B. 120 watts
, C. 1,200 watts
D. 12,000 watts
Answer: C. 1,200 watts
Rationale: Using the basic power relationship P = E × I, the load
consumes 120 volts × 10 amperes = 1,200 watts.
6. What is the purpose of a grounding electrode system?
A. To provide a path for normal load current
B. To establish a connection to earth for the electrical system
C. To replace all circuit breakers
D. To increase conductor ampacity
Answer: B. To establish a connection to earth for the electrical system
Rationale: A grounding electrode system connects the electrical system
to earth. It helps stabilize voltage to earth and provides a reference for
the electrical system, while system and equipment grounding
conductors perform different fault-current functions.
7. Which device is specifically intended to provide protection against
ground-fault shock hazards to people?
