Solution and Answer Guide Illustrated Guide to the
National Electrical Code 9th Edition by Charles R.
Miller
ILLUSTRATED GUIDE TO THE NATIONAL ELECTRICAL CODE, 9TH
ED. (CHARLES R. MILLER)
Chapter 1 — General
Q1. The NEC is primarily intended to:
• A. Ensure efficiency of electrical systems
• B. Provide safety from electrical hazards
• C. Establish pricing for equipment
• D. Define design details for engineers
Answer: B
Rationale: NEC’s scope is safety—minimizing risks of fire and shock. It does
not address cost or design specifics.
Q2. Which authority enforces the NEC locally?
• A. NFPA Board
• B. Authority Having Jurisdiction (AHJ)
• C. Utility company
• D. OSHA exclusively
Answer: B
Rationale: The AHJ interprets and enforces the NEC, often local inspectors.
Q3. Which of the following is not covered by the NEC?
• A. Marine installations regulated by other codes
• B. Dwelling units
, • C. Commercial occupancies
• D. Industrial occupancies
Answer: A
Rationale: NEC excludes ships, railways, and some communications facilities
under other regulations.
Q4. The NEC defines a “qualified person” as:
• A. Anyone with electrical knowledge
• B. An individual with skills and safety training to perform electrical tasks
• C. A licensed engineer only
• D. A certified inspector only
Answer: B
Rationale: A qualified person has demonstrated knowledge and training in
equipment and safety practices.
Q5. Which term means “an electric circuit including conductors between final
overcurrent device and outlet(s)”?
• A. Feeder
• B. Branch circuit
• C. Service conductors
• D. Equipment grounding conductor
Answer: B
Rationale: Branch circuit runs from OCPD to outlets. Feeder runs between
OCPD and other OCPD.
Q6. Which color identifies an equipment grounding conductor?
• A. White
, • B. Green or bare
• C. Red
• D. Blue
Answer: B
Rationale: NEC requires green or bare copper for equipment grounding.
Q7. What does the NEC consider “listed” equipment?
• A. Approved only by manufacturer
• B. Approved by a qualified testing laboratory like UL
• C. Chosen by installer
• D. Recommended by engineer
Answer: B
Rationale: “Listed” = evaluated by recognized independent testing lab.
Q8. What is the purpose of the Nationally Recognized Testing Laboratory
(NRTL)?
• A. Market products
• B. Test and certify products for safety compliance
• C. Issue installation permits
• D. Enforce NEC in the field
Answer: B
Rationale: NRTLs verify that products meet standards for safe installation.
Q9. The NEC is revised every:
• A. 2 years
• B. 3 years
, • C. 5 years
• D. 10 years
Answer: B
Rationale: NEC updates on a 3-year cycle.
Q10. The NEC applies to:
• A. Design details and cost efficiency
• B. Installation of conductors, equipment, and raceways for safe use
• C. Manufacturing processes
• D. Telecom wiring only
Answer: B
Rationale: Scope covers safe installation and use, not cost/design.
Chapter 2 — Wiring and Protection
Q1. Minimum size copper conductor for residential branch circuits:
• A. 10 AWG
• B. 14 AWG
• C. 12 AWG
• D. 16 AWG
Answer: B
Rationale: 14 AWG is minimum size permitted for 15 A circuits.
Q2. Branch circuits supplying receptacles in kitchens must:
• A. Be one 15 A circuit
• B. Be at least two 20 A small-appliance circuits
• C. Share lighting loads
National Electrical Code 9th Edition by Charles R.
Miller
ILLUSTRATED GUIDE TO THE NATIONAL ELECTRICAL CODE, 9TH
ED. (CHARLES R. MILLER)
Chapter 1 — General
Q1. The NEC is primarily intended to:
• A. Ensure efficiency of electrical systems
• B. Provide safety from electrical hazards
• C. Establish pricing for equipment
• D. Define design details for engineers
Answer: B
Rationale: NEC’s scope is safety—minimizing risks of fire and shock. It does
not address cost or design specifics.
Q2. Which authority enforces the NEC locally?
• A. NFPA Board
• B. Authority Having Jurisdiction (AHJ)
• C. Utility company
• D. OSHA exclusively
Answer: B
Rationale: The AHJ interprets and enforces the NEC, often local inspectors.
Q3. Which of the following is not covered by the NEC?
• A. Marine installations regulated by other codes
• B. Dwelling units
, • C. Commercial occupancies
• D. Industrial occupancies
Answer: A
Rationale: NEC excludes ships, railways, and some communications facilities
under other regulations.
Q4. The NEC defines a “qualified person” as:
• A. Anyone with electrical knowledge
• B. An individual with skills and safety training to perform electrical tasks
• C. A licensed engineer only
• D. A certified inspector only
Answer: B
Rationale: A qualified person has demonstrated knowledge and training in
equipment and safety practices.
Q5. Which term means “an electric circuit including conductors between final
overcurrent device and outlet(s)”?
• A. Feeder
• B. Branch circuit
• C. Service conductors
• D. Equipment grounding conductor
Answer: B
Rationale: Branch circuit runs from OCPD to outlets. Feeder runs between
OCPD and other OCPD.
Q6. Which color identifies an equipment grounding conductor?
• A. White
, • B. Green or bare
• C. Red
• D. Blue
Answer: B
Rationale: NEC requires green or bare copper for equipment grounding.
Q7. What does the NEC consider “listed” equipment?
• A. Approved only by manufacturer
• B. Approved by a qualified testing laboratory like UL
• C. Chosen by installer
• D. Recommended by engineer
Answer: B
Rationale: “Listed” = evaluated by recognized independent testing lab.
Q8. What is the purpose of the Nationally Recognized Testing Laboratory
(NRTL)?
• A. Market products
• B. Test and certify products for safety compliance
• C. Issue installation permits
• D. Enforce NEC in the field
Answer: B
Rationale: NRTLs verify that products meet standards for safe installation.
Q9. The NEC is revised every:
• A. 2 years
• B. 3 years
, • C. 5 years
• D. 10 years
Answer: B
Rationale: NEC updates on a 3-year cycle.
Q10. The NEC applies to:
• A. Design details and cost efficiency
• B. Installation of conductors, equipment, and raceways for safe use
• C. Manufacturing processes
• D. Telecom wiring only
Answer: B
Rationale: Scope covers safe installation and use, not cost/design.
Chapter 2 — Wiring and Protection
Q1. Minimum size copper conductor for residential branch circuits:
• A. 10 AWG
• B. 14 AWG
• C. 12 AWG
• D. 16 AWG
Answer: B
Rationale: 14 AWG is minimum size permitted for 15 A circuits.
Q2. Branch circuits supplying receptacles in kitchens must:
• A. Be one 15 A circuit
• B. Be at least two 20 A small-appliance circuits
• C. Share lighting loads
