TN LLE General NEC Requirements 2 — Questions and Answers
Question 1: Per NEC 210.52(A), what is the maximum spacing between receptacle outlets along a wall in a dwelling unit?
- 6 feet
- 8 feet
- 12 feet
- No point along the wall should be more than 6 feet from a receptacle (Correct answer)
Correct answer: No point along the wall should be more than 6 feet from a receptacle
NEC 210.52(A)(1) requires receptacles so that no point along the floor line of any wall space is more than 6 feet from a receptacle outlet.
NEC 210.52(A)(1) uses a 6-foot rule: no point measured horizontally along the floor line in any wall space should be more than 6 feet from a receptacle outlet. This effectively means receptacles are spaced a maximum of 12 feet apart along continuous wall space. Any wall space 2 feet or wider requires a receptacle. The 6-foot measurement was chosen so that a standard 6-foot appliance cord could reach a receptacle from any point along the wall. Doorways, fireplaces, and similar openings break the wall space measurement.
Question 2: What is the minimum number of 20-ampere small-appliance branch circuits required for the kitchen in a dwelling unit per NEC 210.11(C)(1)?
- 1
- 2 (Correct answer)
- 3
- 4
Correct answer: 2
NEC 210.11(C)(1) requires a minimum of two 20-ampere small-appliance branch circuits serving the kitchen and dining areas.
NEC 210.11(C)(1) mandates at least two 20-ampere small-appliance branch circuits to serve all receptacle outlets in the kitchen, pantry, breakfast room, dining room, and similar areas. These circuits may supply no other outlets except for a clock outlet and supplemental equipment in these rooms. The two circuits must serve the kitchen countertop receptacles, and both must be accessible in the kitchen area. This ensures that multiple high-draw kitchen appliances can operate simultaneously without overloading a single circuit.
Question 3: Per NEC 210.52(C), what is the maximum distance a countertop receptacle can be from the end of a kitchen countertop that is 12 inches or wider?
- 12 inches
- 24 inches (Correct answer)
- No specific requirement
- A receptacle must be within the first 24 inches of the countertop end
Correct answer: 24 inches
NEC 210.52(C)(1) requires a receptacle outlet within 24 inches of each end of a continuous countertop space that is 12 inches or wider.
NEC 210.52(C)(1) requires that receptacle outlets be installed so that no point along the countertop wall line is more than 24 inches (measured horizontally) from a receptacle. Additionally, a receptacle outlet must be placed within 24 inches of each end of a countertop space that is 12 inches or wider. Countertop spaces separated by range tops, sinks, or refrigerators are considered separate spaces. Island and peninsular countertops with dimensions of 24 inches x 12 inches or greater also require at least one receptacle.
Question 4: Per NEC 210.12, where is AFCI protection required in a dwelling unit?
- Only bedrooms
- Bedrooms and living rooms
- All areas except bathrooms, garages, and outdoors (Correct answer)
- Every room including bathrooms
Correct answer: All areas except bathrooms, garages, and outdoors
NEC 210.12(A) requires AFCI protection for 120V, 15- and 20-ampere branch circuits supplying outlets in most dwelling unit areas, with specific exemptions.
NEC 210.12(A) requires AFCI protection for virtually all 120V, 15A and 20A branch circuits supplying outlets in dwelling units including kitchens, family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas, and similar rooms. Notable exceptions include bathrooms, garages, and outdoor areas (which are GFCI-protected instead). The protection can be provided by AFCI circuit breakers, outlet-branch-circuit-type AFCIs, or listed combinations.
Question 5: What is the minimum service size required for a single-family dwelling per NEC 230.79(C)?
- 60 amperes
- 100 amperes (Correct answer)
- 150 amperes
- 200 amperes
Correct answer: 100 amperes
NEC 230.79(C) requires that a single-family dwelling service have a minimum rating of 100 amperes, 3-wire.
NEC 230.79(C) sets the minimum service rating for a single-family dwelling at 100 amperes, 3-wire. While this is the code minimum, most modern homes in Tennessee are installed with 200A services to accommodate increased electrical loads from HVAC systems, electric dryers, ranges, and the growing adoption of electric vehicle chargers. Local jurisdictions may adopt amendments requiring larger minimum service sizes. For the TN LLE exam, know that 100A is the NEC minimum, but practical installations typically use 200A.
Question 6: Per NEC 314.16, how is the volume allowance calculated for device boxes?
- By counting only the number of conductors
- By counting conductors, devices, clamps, and grounding conductors using specific volume allowances (Correct answer)
- By measuring the physical box dimensions only
- By the wire gauge size only
Correct answer: By counting conductors, devices, clamps, and grounding conductors using specific volume allowances
NEC 314.16(B) requires counting conductors and assigning volume allowances based on conductor size, plus allowances for devices, clamps, and equipment grounding conductors.
NEC 314.16(B) box fill calculation includes: each conductor entering the box counts as one volume allowance based on size (14 AWG = 2.0 cubic inches, 12 AWG = 2.25 cubic inches). Internal cable clamps count as one conductor volume (of the largest conductor). Each yoke/strap with a device counts as two conductor volumes. All equipment grounding conductors combined count as one conductor volume of the largest EGC. Conductors that pass through without splice count as one. This calculation ensures adequate space for safe connections and heat dissipation.
TN LLE General NEC Requirements 2
Per NEC 210.52(A), what is the maximum spacing between receptacle outlets along a wall in a dwelling unit?