Questions And Correct Answers
1. What is the primary purpose of the grounding electrode system?
A. To provide a return path for normal current
B. To stabilize the system voltage to earth
C. To energize non–current-carrying metal parts
D. To reduce conductor size
Answer: B
Rationale: The grounding electrode system stabilizes voltage to earth and
limits voltage from lightning, surges, and unintentional contact with higher-
voltage lines.
2. Which conductor is permitted to be bare?
A. Grounded conductor
B. Ungrounded conductor
C. Equipment grounding conductor
D. Neutral feeder conductor
Answer: C
Rationale: Equipment grounding conductors may be bare, covered, or insulated
as permitted by code.
3. What is the minimum working space depth required in front of
electrical equipment rated 0–150 volts to ground?
A. 24 inches
B. 30 inches
C. 36 inches
D. 42 inches
Answer: C
Rationale: A minimum of 36 inches of clear working space is required for
,equipment up to 150 volts to ground.
4. Which type of load operates for three hours or more?
A. Noncontinuous load
B. Intermittent load
C. Continuous load
D. Variable load
Answer: C
Rationale: A continuous load is defined as one where the maximum current is
expected to continue for three hours or more.
5. Branch-circuit conductors supplying a continuous load must be sized at
least:
A. 100% of the load
B. 110% of the load
C. 125% of the load
D. 150% of the load
Answer: C
Rationale: Conductors must be sized at 125% of the continuous load to prevent
overheating.
6. What is the maximum allowable voltage drop for a branch circuit
recommended for efficiency?
A. 2%
B. 3%
C. 4%
D. 5%
Answer: B
Rationale: A 3% maximum voltage drop is recommended for branch circuits to
ensure proper equipment operation.
7. Which device is designed to protect against ground faults of
equipment?
A. AFCI
B. Circuit breaker
C. GFCI
D. Fuse
, Answer: C
Rationale: Ground-Fault Circuit Interrupters protect people by detecting
leakage current to ground.
8. What color insulation identifies the grounded conductor in a 120/208-volt
system?
A. Green
B. Bare
C. White or gray
D. Red
Answer: C
Rationale: White or gray insulation identifies the grounded (neutral) conductor.
9. Which type of overcurrent device provides both overload and short-
circuit protection?
A. Thermal relay
B. Fuse
C. Contactor
D. Disconnect switch
Answer: B
Rationale: Fuses are designed to open under overload and short-circuit
conditions.
10. What is the minimum burial depth for rigid metal conduit under a
residential driveway?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
Answer: C
Rationale: Rigid metal conduit requires a minimum burial depth of 18 inches
under driveways.
11. When must an AFCI be installed?
A. Only in kitchens
B. In all industrial occupancies
C. In dwelling unit living areas