NEC ELECTRIC 3 — Questions and Answers
Question 1: A 20-ampere small-appliance branch circuit in a kitchen must use a minimum copper conductor size of:
- 14 AWG
- 12 AWG (Correct answer)
- 10 AWG
- 8 AWG
Correct answer: 12 AWG
A 20-amp circuit requires a minimum 12 AWG copper conductor.
Question 2: What is the maximum allowable voltage drop recommended by the NEC for a branch circuit?
- 1%
- 3% (Correct answer)
- 8%
- 10%
Correct answer: 3%
The NEC recommends a maximum 3% voltage drop on a branch circuit for reasonable efficiency.
Question 3: Which conductor must never be used as a current-carrying conductor under normal operation?
- Ungrounded conductor
- Grounded neutral conductor
- Equipment grounding conductor (Correct answer)
- Phase conductor
Correct answer: Equipment grounding conductor
The equipment grounding conductor carries current only during a fault, never under normal operation.
Question 4: Receptacles installed outdoors at a dwelling must be protected by:
- AFCI only
- GFCI and a weatherproof cover (Correct answer)
- Surge protection
- A 30-amp breaker
Correct answer: GFCI and a weatherproof cover
Outdoor receptacles require GFCI protection and a weatherproof in-use cover.
Question 5: The grounding electrode conductor connects the service to the:
- Main breaker
- Grounding electrode (such as a ground rod) (Correct answer)
- Neutral bus only
- Load center cover
Correct answer: Grounding electrode (such as a ground rod)
The grounding electrode conductor bonds the system to the grounding electrode like a ground rod.
Question 6: What is the minimum height clearance for overhead service-drop conductors above a residential driveway?
- 10 feet
- 12 feet (Correct answer)
- 15 feet
- 18 feet
Correct answer: 12 feet
Service-drop conductors must maintain at least 12 feet of clearance over residential driveways.
Question 7: Tamper-resistant receptacles are required in dwelling units to:
- Increase amperage
- Prevent children from inserting objects (Correct answer)
- Reduce voltage drop
- Eliminate the neutral
Correct answer: Prevent children from inserting objects
Tamper-resistant receptacles have shutters that prevent children from inserting foreign objects.
NEC ELECTRIC 3
A 20-ampere small-appliance branch circuit in a kitchen must use a minimum copper conductor size of: