Free TN-LLE General NEC Requirements Questions and Answers 1 — Questions and Answers
Question 1: What is the primary purpose of the National Electrical Code (NEC)?
- To serve as a design specification for electrical installations
- The practical safeguarding of persons and property from hazards arising from the use of electricity (Correct answer)
- To provide a guide for training qualified electricians
- To ensure the efficient use of electricity
Correct answer: The practical safeguarding of persons and property from hazards arising from the use of electricity
NEC 90.1(A) explicitly states that the purpose of the Code is the practical safeguarding of persons and property from hazards arising from the use of electricity. It is not intended as a design manual or an instruction manual for untrained persons.
Question 2: In the NEC, what does the term "Readily Accessible" mean?
- Capable of being reached for operation, but may require a portable ladder.
- Capable of being reached quickly for operation, renewal, or inspections without requiring tools to open doors or climbing over obstacles. (Correct answer)
- Admitting close approach; not guarded by locked doors or elevation.
- Visible and not more than 50 feet distant from the equipment.
Correct answer: Capable of being reached quickly for operation, renewal, or inspections without requiring tools to open doors or climbing over obstacles.
Article 100 defines "Readily Accessible" as capable of being reached quickly for operation or inspection without requiring tools to open doors, climbing over obstacles, or using a portable ladder. This is a higher level of accessibility than just "Accessible."
Question 3: A 240/120-volt panelboard is installed in a basement opposite a concrete wall. What is the minimum required depth of working space in front of this panelboard?
- 30 inches
- 3 feet (Correct answer)
- 4 feet
- 3.5 feet
Correct answer: 3 feet
According to NEC Table 110.26(A)(1), for a system with a nominal voltage to ground of 150 volts or less (120V in this case), the minimum clearance for Condition 2 (exposed live parts on one side and grounded parts, like a concrete wall, on the other) is 3 feet.
Question 4: Which word used in the National Electrical Code indicates a mandatory rule?
- Should
- May
- Shall (Correct answer)
- Could
Correct answer: Shall
NEC 90.5(A) states that mandatory rules of the Code are characterized by the use of the word "shall." Following these rules is required for a compliant installation. The word "should" is used in informational notes and is not enforceable.
Question 5: An electrical enclosure is to be installed outdoors, exposed to rain and sleet. Which NEMA enclosure type is the minimum requirement for this location?
- Type 1
- Type 2
- Type 3R (Correct answer)
- Type 12
Correct answer: Type 3R
A NEMA Type 3R enclosure is constructed for either indoor or outdoor use to provide a degree of protection against ingress of solid foreign objects (falling dirt) and water (rain, sleet, snow). It is a common choice for residential service equipment and outdoor disconnects.
Question 6: According to NEC 110.16(A), service equipment in other than dwelling units that is likely to require examination while energized must be field marked to warn of what specific hazard?
- High Voltage
- Electric Shock Hazard
- Potential Arc-Flash Hazards (Correct answer)
- Lockout/Tagout Required
Correct answer: Potential Arc-Flash Hazards
NEC 110.16(A) requires that such equipment be field-marked to warn qualified persons of potential electric arc-flash hazards. The marking must be located so it is clearly visible to qualified persons before they examine, adjust, service, or perform maintenance on the equipment.
Free TN-LLE General NEC Requirements Questions and Answers 1
What is the primary purpose of the National Electrical Code (NEC)?