CO Journeyman Electrician Exam
Practice Questions And Correct
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1. Which edition of the National Electrical Code (NEC) is generally used
as the primary technical standard for electrical installations in
Colorado, subject to the applicable state and local adoption
requirements?
A. 2014 NEC
B. 2017 NEC
C. 2020 NEC
D. 2023 NEC
The 2023 NEC is the current national model code edition relevant to
Colorado electrical work, although electricians must also comply with
the specific Colorado amendments and local requirements applicable to
the project.
2. Under the NEC, what is the primary purpose of a circuit breaker?
A. To increase circuit voltage
B. To reduce conductor resistance
,C. To protect conductors against overcurrent
D. To improve power factor
A circuit breaker opens the circuit when current exceeds the permitted
value, protecting conductors and connected equipment from excessive
heating and potential fire hazards.
3. A 120-volt branch circuit supplies a continuous load of 16 amperes.
What is the minimum ampere rating required for the branch circuit
overcurrent device when the circuit is designed using the NEC 125%
continuous-load rule?
A. 16 A
B. 18 A
C. 20 A
D. 25 A
A continuous load is generally calculated at 125% for conductor and
overcurrent protection sizing. Sixteen amperes multiplied by 1.25 equals
20 amperes.
4. What is the minimum copper conductor size normally permitted for
a 20-ampere general-purpose branch circuit under the NEC,
assuming no adjustment, correction, or special application requires
a larger conductor?
A. 14 AWG
B. 12 AWG
,C. 10 AWG
D. 8 AWG
A 20-ampere branch circuit generally requires a minimum 12 AWG
copper conductor under the standard ampacity provisions, subject to
applicable NEC conditions and limitations.
5. What is the principal function of the equipment grounding
conductor in a branch circuit?
A. Carry normal load current
B. Increase circuit voltage
C. Reduce the operating frequency
D. Provide a low-impedance path for fault current
The equipment grounding conductor provides a conductive path
intended to facilitate operation of the overcurrent device when a fault
energizes normally non-current-carrying metal parts.
6. A receptacle is installed in a location where personnel may come
into contact with grounded surfaces while using electrical
equipment. Which protection is generally required where the NEC
identifies the location as requiring ground-fault protection?
A. AFCI protection only
B. Surge protection only
C. GFCI protection
D. Overvoltage protection only
, A ground-fault circuit interrupter monitors current imbalance and
disconnects power when leakage to ground reaches its trip threshold,
reducing the risk of severe electric shock.
7. What is the fundamental operating principle of a GFCI device?
A. It measures conductor temperature
B. It detects excessive line voltage
C. It compares current leaving and returning through the circuit
conductors
D. It measures the resistance of the grounding electrode
A GFCI detects an imbalance between outgoing and returning current,
indicating that some current may be flowing through an unintended
path such as a person to ground.
8. Which type of protection is specifically intended to reduce the
likelihood of fires caused by arcing faults in electrical wiring?
A. GFCI
B. Surge protective device
C. Thermal overload relay
D. AFCI
An arc-fault circuit interrupter detects characteristic dangerous arcing
conditions and disconnects the circuit to help prevent ignition of
surrounding combustible materials.
9. What is the purpose of a junction box?
Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant
Download Pdf.
1. Which edition of the National Electrical Code (NEC) is generally used
as the primary technical standard for electrical installations in
Colorado, subject to the applicable state and local adoption
requirements?
A. 2014 NEC
B. 2017 NEC
C. 2020 NEC
D. 2023 NEC
The 2023 NEC is the current national model code edition relevant to
Colorado electrical work, although electricians must also comply with
the specific Colorado amendments and local requirements applicable to
the project.
2. Under the NEC, what is the primary purpose of a circuit breaker?
A. To increase circuit voltage
B. To reduce conductor resistance
,C. To protect conductors against overcurrent
D. To improve power factor
A circuit breaker opens the circuit when current exceeds the permitted
value, protecting conductors and connected equipment from excessive
heating and potential fire hazards.
3. A 120-volt branch circuit supplies a continuous load of 16 amperes.
What is the minimum ampere rating required for the branch circuit
overcurrent device when the circuit is designed using the NEC 125%
continuous-load rule?
A. 16 A
B. 18 A
C. 20 A
D. 25 A
A continuous load is generally calculated at 125% for conductor and
overcurrent protection sizing. Sixteen amperes multiplied by 1.25 equals
20 amperes.
4. What is the minimum copper conductor size normally permitted for
a 20-ampere general-purpose branch circuit under the NEC,
assuming no adjustment, correction, or special application requires
a larger conductor?
A. 14 AWG
B. 12 AWG
,C. 10 AWG
D. 8 AWG
A 20-ampere branch circuit generally requires a minimum 12 AWG
copper conductor under the standard ampacity provisions, subject to
applicable NEC conditions and limitations.
5. What is the principal function of the equipment grounding
conductor in a branch circuit?
A. Carry normal load current
B. Increase circuit voltage
C. Reduce the operating frequency
D. Provide a low-impedance path for fault current
The equipment grounding conductor provides a conductive path
intended to facilitate operation of the overcurrent device when a fault
energizes normally non-current-carrying metal parts.
6. A receptacle is installed in a location where personnel may come
into contact with grounded surfaces while using electrical
equipment. Which protection is generally required where the NEC
identifies the location as requiring ground-fault protection?
A. AFCI protection only
B. Surge protection only
C. GFCI protection
D. Overvoltage protection only
, A ground-fault circuit interrupter monitors current imbalance and
disconnects power when leakage to ground reaches its trip threshold,
reducing the risk of severe electric shock.
7. What is the fundamental operating principle of a GFCI device?
A. It measures conductor temperature
B. It detects excessive line voltage
C. It compares current leaving and returning through the circuit
conductors
D. It measures the resistance of the grounding electrode
A GFCI detects an imbalance between outgoing and returning current,
indicating that some current may be flowing through an unintended
path such as a person to ground.
8. Which type of protection is specifically intended to reduce the
likelihood of fires caused by arcing faults in electrical wiring?
A. GFCI
B. Surge protective device
C. Thermal overload relay
D. AFCI
An arc-fault circuit interrupter detects characteristic dangerous arcing
conditions and disconnects the circuit to help prevent ignition of
surrounding combustible materials.
9. What is the purpose of a junction box?
