Questions and Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A | Instant
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1. According to the NEC, what is the primary purpose of grounding
electrical systems?
A. To increase voltage
B. To reduce current flow
C. To limit voltage imposed by lightning, line surges, or unintentional
contact with higher-voltage lines and stabilize voltage to ground
D. To reduce conductor resistance
Rationale: System grounding helps stabilize voltage during normal
operation and provides protection from lightning, surges, and
accidental contact with higher-voltage systems. Grounding also assists
in facilitating the operation of overcurrent protective devices during
fault conditions.
, 2. Which NEC article covers the general requirements for grounding
and bonding?
A. Article 110
B. Article 220
C. Article 250
D. Article 300
Correct Answer: C. Article 250
Rationale: NEC Article 250 contains comprehensive requirements for
grounding and bonding, including grounding electrodes, equipment
grounding conductors, bonding jumpers, and grounding electrode
conductors.
3. What is the minimum working space depth for equipment
operating at 0–150 volts to ground under Condition 1?
A. 24 inches
B. 36 inches
C. 42 inches
D. 48 inches
,Rationale: NEC 110.26 requires a minimum working space depth of 3
feet (36 inches) for equipment operating at 0–150 volts to ground
under Condition 1 to allow safe servicing.
4. Which conductor is intentionally connected to ground?
A. Equipment grounding conductor
B. Equipment bonding jumper
C. Grounded conductor
D. Grounding electrode conductor
Rationale: The grounded conductor, typically the neutral, is
intentionally connected to ground at the service disconnecting means.
5. What color is commonly used to identify an equipment grounding
conductor?
A. White
B. Gray
C. Black
D. Green or bare
, Rationale: NEC requires equipment grounding conductors to be
identified by a continuous green finish, green with yellow stripes, or
be bare where permitted.
6. Which overcurrent device protects conductors primarily from
overloads and short circuits?
A. Switch
B. Relay
C. Circuit breaker
D. Contactor
Rationale: Circuit breakers automatically interrupt excessive current
caused by overloads or short circuits, protecting conductors from
overheating and damage.
7. What is the minimum cover for rigid metal conduit installed under
a residential driveway?
A. 6 inches
B. 12 inches
C. 18 inches