NASCLA National Electrical Journeyman Exam
(Alabama Candidate) – Mock Test and Study Guide
SECTION A: GENERAL ELECTRICAL KNOWLEDGE
1. What is the primary purpose of grounding an electrical system?
• A) Reduce voltage drop
• B) Provide a path for fault current
• C) Increase current capacity
• D) Prevent overloads
Answer: B) Provide a path for fault current
Rationale: Grounding provides a low-impedance path to safely clear ground faults
and reduce shock hazards .
2. In a purely resistive DC circuit, if the voltage is doubled while resistance
remains constant, the power consumed will:
• A) Remain the same
• B) Double
• C) Quadruple
• D) Halve
Answer: C) Quadruple
Rationale: Power P = V²/R. Doubling V causes P to increase by a factor of four.
3. What is the maximum number of current-carrying conductors permitted in a
single conduit before derating applies?
, • A) 3
• B) 6
• C) 9
• D) Any number
Answer: A) 3
Rationale: Derating begins when more than three current-carrying conductors are
installed in a conduit .
4. What is the maximum allowable voltage drop recommended for branch
circuits?
• A) 1%
• B) 3%
• C) 5%
• D) 10%
Answer: B) 3%
Rationale: The NEC recommends no more than 3% voltage drop on branch circuits,
with total feeder and branch circuit drop not exceeding 5% .
5. What does the term "ampacity" mean?
• A) Maximum voltage rating
• B) Maximum current a conductor can carry safely
• C) Maximum fault current
• D) Minimum breaker size
,Answer: B) Maximum current a conductor can carry safely
Rationale: Ampacity is based on insulation, temperature rating, and installation
conditions .
6. Which conductor is intentionally grounded in a typical 120/240V single-phase
system?
• A) Equipment grounding conductor
• B) Neutral conductor
• C) Ungrounded conductor
• D) Bonding jumper
Answer: B) Neutral conductor
Rationale: The neutral is the grounded conductor connected to earth at the
service .
7. What color insulation identifies the equipment grounding conductor?
• A) White
• B) Gray
• C) Green or green with yellow stripe
• D) Black
Answer: C) Green or green with yellow stripe
Rationale: NEC 250.119 requires equipment grounding conductors to be identified
by green or green with yellow stripe insulation .
8. The opposition to current flow in an AC circuit caused by capacitance is called:
• A) Inductive reactance
, • B) Capacitive reactance
• C) Impedance
• D) Resistance
Answer: B) Capacitive reactance
Rationale: Capacitive reactance (XC = 1/2πfC) is the opposition to AC current flow
caused by capacitance.
9. A 1,800-watt lighting circuit at 120 V draws how many amps?
• A) 10 A
• B) 12 A
• C) 15 A
• D) 20 A
Answer: C) 15 A
Rationale: I = P ÷ V = 1800 ÷ 120 = 15 A. This is a fundamental load calculation for
determining branch circuit requirements.
10. A transformer with a 10:1 turns ratio has 240 V input. What is the
approximate output voltage?
• A) 12 V
• B) 24 V
• C) 120 V
• D) 240 V
Answer: B) 24 V
Rationale: V_out = V_in × (N_out ÷ N_in) = 240 × (1 ÷ 10) = 24 V.
(Alabama Candidate) – Mock Test and Study Guide
SECTION A: GENERAL ELECTRICAL KNOWLEDGE
1. What is the primary purpose of grounding an electrical system?
• A) Reduce voltage drop
• B) Provide a path for fault current
• C) Increase current capacity
• D) Prevent overloads
Answer: B) Provide a path for fault current
Rationale: Grounding provides a low-impedance path to safely clear ground faults
and reduce shock hazards .
2. In a purely resistive DC circuit, if the voltage is doubled while resistance
remains constant, the power consumed will:
• A) Remain the same
• B) Double
• C) Quadruple
• D) Halve
Answer: C) Quadruple
Rationale: Power P = V²/R. Doubling V causes P to increase by a factor of four.
3. What is the maximum number of current-carrying conductors permitted in a
single conduit before derating applies?
, • A) 3
• B) 6
• C) 9
• D) Any number
Answer: A) 3
Rationale: Derating begins when more than three current-carrying conductors are
installed in a conduit .
4. What is the maximum allowable voltage drop recommended for branch
circuits?
• A) 1%
• B) 3%
• C) 5%
• D) 10%
Answer: B) 3%
Rationale: The NEC recommends no more than 3% voltage drop on branch circuits,
with total feeder and branch circuit drop not exceeding 5% .
5. What does the term "ampacity" mean?
• A) Maximum voltage rating
• B) Maximum current a conductor can carry safely
• C) Maximum fault current
• D) Minimum breaker size
,Answer: B) Maximum current a conductor can carry safely
Rationale: Ampacity is based on insulation, temperature rating, and installation
conditions .
6. Which conductor is intentionally grounded in a typical 120/240V single-phase
system?
• A) Equipment grounding conductor
• B) Neutral conductor
• C) Ungrounded conductor
• D) Bonding jumper
Answer: B) Neutral conductor
Rationale: The neutral is the grounded conductor connected to earth at the
service .
7. What color insulation identifies the equipment grounding conductor?
• A) White
• B) Gray
• C) Green or green with yellow stripe
• D) Black
Answer: C) Green or green with yellow stripe
Rationale: NEC 250.119 requires equipment grounding conductors to be identified
by green or green with yellow stripe insulation .
8. The opposition to current flow in an AC circuit caused by capacitance is called:
• A) Inductive reactance
, • B) Capacitive reactance
• C) Impedance
• D) Resistance
Answer: B) Capacitive reactance
Rationale: Capacitive reactance (XC = 1/2πfC) is the opposition to AC current flow
caused by capacitance.
9. A 1,800-watt lighting circuit at 120 V draws how many amps?
• A) 10 A
• B) 12 A
• C) 15 A
• D) 20 A
Answer: C) 15 A
Rationale: I = P ÷ V = 1800 ÷ 120 = 15 A. This is a fundamental load calculation for
determining branch circuit requirements.
10. A transformer with a 10:1 turns ratio has 240 V input. What is the
approximate output voltage?
• A) 12 V
• B) 24 V
• C) 120 V
• D) 240 V
Answer: B) 24 V
Rationale: V_out = V_in × (N_out ÷ N_in) = 240 × (1 ÷ 10) = 24 V.
