NEC General Electrical Theory & Code Definitions 2 — Questions and Answers
Question 1: Under the NEC, what is the definition of a 'branch circuit'?
- The circuit conductors between the final overcurrent device and the outlet(s) (Correct answer)
- The conductors from the service entrance to the panelboard
- The wiring from the meter base to the main disconnect
- The conductors supplying a single motor
Correct answer: The circuit conductors between the final overcurrent device and the outlet(s)
NEC Article 100 defines a branch circuit as the circuit conductors between the final overcurrent device protecting the circuit and the outlet(s).
Question 2: Which NEC term describes equipment that has been tested and listed by a nationally recognized testing laboratory?
- Approved
- Listed (Correct answer)
- Labeled
- Identified
Correct answer: Listed
NEC Article 100 defines 'listed' as equipment that has been evaluated by a nationally recognized testing laboratory and found to meet specific requirements.
Question 3: What is the NEC definition of 'ampacity'?
- The maximum voltage a conductor can withstand
- The current in amperes a conductor can carry continuously under use conditions without exceeding its temperature rating (Correct answer)
- The fault current available at a given point
- The rated capacity of an overcurrent device
Correct answer: The current in amperes a conductor can carry continuously under use conditions without exceeding its temperature rating
Ampacity is defined in NEC Article 100 as the current in amperes that a conductor can carry continuously under the conditions of use without exceeding its temperature rating.
Question 4: According to NEC Article 100, what is a 'feeder'?
- Any circuit supplying a single receptacle
- All circuit conductors between the service equipment and the final branch-circuit overcurrent device (Correct answer)
- The conductors between the meter and the main panel
- A conductor that supplies more than one branch circuit
Correct answer: All circuit conductors between the service equipment and the final branch-circuit overcurrent device
A feeder is defined as all circuit conductors between the service equipment, the source of a separately derived system, or other supply source and the final branch-circuit overcurrent device.
Question 5: What does the NEC term 'identified' mean when applied to equipment or conductors?
- Approved by the authority having jurisdiction
- Recognizable as suitable for a specific purpose, function, or use (Correct answer)
- Listed by a nationally recognized testing laboratory
- Marked with the manufacturer's name
Correct answer: Recognizable as suitable for a specific purpose, function, or use
Per NEC Article 100, 'identified' means recognizable as suitable for the specific purpose, function, use, environment, or application.
Question 6: In electrical theory, if voltage remains constant and resistance doubles, what happens to current?
- Current doubles
- Current remains the same
- Current is halved (Correct answer)
- Current increases by the square root of 2
Correct answer: Current is halved
By Ohm's Law (I = V/R), if voltage is constant and resistance doubles, the current is halved.
Question 7: What is the NEC definition of 'dwelling unit'?
- Any building used primarily for sleeping
- A single unit providing complete and independent living facilities for one or more persons (Correct answer)
- Any residential occupancy with a kitchen
- A structure containing no more than four living spaces
Correct answer: A single unit providing complete and independent living facilities for one or more persons
NEC Article 100 defines a dwelling unit as a single unit providing complete and independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking, and sanitation.
NEC General Electrical Theory & Code Definitions 2
Under the NEC, what is the definition of a 'branch circuit'?