NEC General Requirements and Definitions 2 — Questions and Answers
Question 1: Under NEC Article 100, what is the definition of 'ampacity'?
- The maximum voltage a conductor can carry continuously
- The current in amperes a conductor can carry continuously under conditions of use without exceeding its temperature rating (Correct answer)
- The resistance of a conductor measured in ohms per foot
- The short-circuit current rating of a protective device
Correct answer: The current in amperes a conductor can carry continuously under conditions of use without exceeding its temperature rating
Ampacity is defined in Article 100 as the current in amperes a conductor can carry continuously under the conditions of use without exceeding its temperature rating.
Question 2: What does the NEC term 'listed' mean when applied to equipment?
- The equipment appears in a manufacturer's product catalog
- Equipment that has been evaluated by a nationally recognized testing laboratory and found to meet applicable standards (Correct answer)
- Equipment approved by the local authority having jurisdiction only
- Equipment that has been installed and inspected at least once
Correct answer: Equipment that has been evaluated by a nationally recognized testing laboratory and found to meet applicable standards
Listed equipment has been evaluated by a qualified electrical testing laboratory and found to meet applicable standards for safety.
Question 3: How does the NEC define a 'branch circuit'?
- The conductors from the utility transformer to the service entrance
- The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s) (Correct answer)
- Any wiring method installed inside conduit
- The wiring between two panelboards in the same building
Correct answer: The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s)
A branch circuit consists of the circuit conductors between the final overcurrent protective device and the outlet(s) it serves.
Question 4: According to NEC Article 100, what is a 'raceway'?
- An enclosed channel designed expressly for holding wires, cables, or busbars (Correct answer)
- A cable tray used only in industrial occupancies
- Any metallic conduit approved for outdoor use
- A wireway used exclusively for low-voltage systems
Correct answer: An enclosed channel designed expressly for holding wires, cables, or busbars
A raceway is an enclosed channel of metallic or nonmetallic materials designed expressly for holding wires, cables, or busbars.
Question 5: Under NEC Section 110.3(B), installed equipment must be used in accordance with:
- The NEMA guidelines only
- Any instructions provided by the installing electrician
- Any listing or labeling instructions included with the equipment (Correct answer)
- The most recent manufacturer's catalog specifications
Correct answer: Any listing or labeling instructions included with the equipment
NEC 110.3(B) requires that listed or labeled equipment be installed and used in accordance with any instructions included in the listing or labeling.
Question 6: What NEC term describes equipment acceptable to the authority having jurisdiction for a specific installation?
- Listed
- Labeled
- Approved (Correct answer)
- Identified
Correct answer: Approved
Approved means acceptable to the authority having jurisdiction and can apply to equipment evaluated specifically for a particular installation rather than bearing a general listing.
Question 7: According to NEC Article 100, what distinguishes a 'grounded conductor' from a 'grounding conductor'?
- A grounded conductor carries fault current; a grounding conductor carries load current
- A grounded conductor is a current-carrying conductor intentionally connected to ground; a grounding conductor connects equipment to ground for safety (Correct answer)
- There is no difference — both terms are interchangeable in the NEC
- A grounded conductor is used only in 3-phase systems; a grounding conductor is used in single-phase systems
Correct answer: A grounded conductor is a current-carrying conductor intentionally connected to ground; a grounding conductor connects equipment to ground for safety
The grounded conductor (neutral) is intentionally connected to ground and carries current during normal operation, while the grounding conductor (EGC) connects non-current-carrying metal parts to ground for fault protection.
NEC General Requirements and Definitions 2
Under NEC Article 100, what is the definition of 'ampacity'?