North Carolina Residential Single-Family Dwelling Electrical Contractor Licensing Exam Questions and Answers | 2026 Update | 100% Correct. PDF

1. A residential electrical contractor is wiring a new single-family dwelling. The service disconnecting means for a 200-amp, single-phase residential service must be located where? A) Inside the master bedroom closet for accessibility B) At the rear of the dwelling farthest from the utility transformer C) At a readily accessible location either inside or outside the dwelling nearest the point of entrance of the service conductors D) Within the attic space above the garage Correct Answer: C Rationale: According to the North Carolina Residential Code and NEC 230.70(A)(1), the service disconnecting means must be installed at a readily accessible location either outside the building or inside nearest the point of entrance of the service conductors. This ensures that emergency responders (firefighters) and utility workers can quickly disconnect power in an emergency without having to search through living spaces. Closets, attics, and basements with storage are not considered "readily accessible" unless specifically designed for that purpose. 2. A grounding electrode system for a new home must include a minimum of how many grounding electrodes unless it is proven that a single electrode has a resistance of 25 ohms or less? A) One B) TwoC) Three D) Four Correct Answer: B Rationale: NEC 250.53(A)(2) requires that if a single grounding electrode (such as a ground rod) has a resistance greater than 25 ohms to earth, one additional electrode must be installed. In practice, to avoid testing costs, most residential contractors in NC install two ground rods spaced at least 6 feet apart by default to comply with this requirement without needing to perform resistance testing. 3. In a single-family dwelling, what is the maximum height above the floor that a wall switch controlling a permanently installed light fixture can be placed to be considered "readily accessible"? A) 5 feet B) 6 feet 7 inches C) 7 feet D) 8 feet Correct Answer: B Rationale: NEC 404.8(A) specifies that switches must be installed so that the center of the grip of the operating handle, when in the highest position, is not more than 6 feet 7 inches (2.0 m) above the floor or working platform. This is a universal accessibility requirement to ensure that the average person can reach the switch without requiring a step stool. 4. When installing Type NM (Romex) cable in a residential attic that is accessible by a pull-down stair, what protection is required for the cable running perpendicular to the joists within 6 feet of the scuttle hole? A) No protection is required if the cable is secured every 4.5 feet B) Guard strips or running boards C) The cable must be derated to 50% ampacity D) Metal conduit onlyCorrect Answer: B Rationale: NEC 320.23(A) (and applicable sections for NM cable) require that where cables are installed in an attic that is accessible, they must be protected by substantial guard strips or running boards if they are within 6 feet of the scuttle hole or attic entrance and run across the top of floor joists. This prevents someone stepping on the cable and damaging the insulation while walking through the attic. 5. What is the minimum required ampacity for a feeder supplying a 120/240-volt, single-family dwelling with a calculated load of 150 amps using the Standard Method? A) 150 amps B) 160 amps C) 175 amps D) 200 amps Correct Answer: A Rationale: NEC 310.12 (formerly 310.15(B)(7)) allows for a reduced service or feeder conductor size for dwelling units. However, the service or feeder rating (the overcurrent protection device) must be at least the calculated load. If the calculated load is 150A, the minimum service rating is 150A. The conductor ampacity must be sufficient for the load, though Table 310.12 permits 4/0 AWG aluminum for 175A or 2/0 AWG copper for 150A in residential applications. 6. AFCI protection is required for which of the following areas in a new single-family dwelling in North Carolina? A) Bathroom receptacle outlets only B) Kitchen receptacle outlets only C) All 120-volt, 15 and 20-amp branch circuits supplying outlets in dwelling units D) Garage door opener receptacles only Correct Answer: C Rationale: As of the current adopted NEC version in NC (with amendments), AFCI (ArcFault Circuit Interrupter) protection is required for nearly all 120-volt, 15 and 20-ampbranch circuits supplying outlets in dwelling units. This includes bedrooms, living rooms, kitchens, laundry areas, and hallways. While bathrooms and garages often have GFCI requirements, they also require AFCI unless exempted by local amendments (though the trend is towards broad coverage). 7. A homeowner requests a ceiling fan installation in a bedroom where the existing plastic octagon box is currently just a light. What must the electrical contractor do regarding the box? A) Install a fan-rated box that is listed for ceiling fan support B) Leave the plastic box as it is because it supports the light C) Add a wooden brace in the attic but keep the plastic box D) Install a metal box with a plaster ring Correct Answer: A Rationale: NEC 314.27(D) requires that outlet boxes used for ceiling-suspended (fans) must be listed and marked as suitable for the support of a ceiling fan. Standard light fixture boxes are not rated for the dynamic load (vibration and torque) caused by a rotating fan. Failure to use a fan-rated box is a major safety hazard and a code violation in North Carolina. 8. What is the minimum burial depth for direct burial Type UF cable in a residential yard for a circuit rated 120 volts or less with GFCI protection? A) 6 inches B) 12 inches C) 18 inches D) 24 inches Correct Answer: B Rationale: NEC Table 300.5 specifies that direct burial cables (UF) for residential branch circuits rated 120 volts or less, with GFCI protection, and with overcurrent protection not exceeding 20 amps, require a minimum cover of 12 inches. If GFCI protection is not utilized, or the voltage is higher, the depth increases to 24 inches.9. The main bonding jumper in a residential service panel serves what critical purpose? A) It provides a path for ground fault current to open the overcurrent device B) It reduces the voltage drop on the neutral conductor C) It bonds the metal gas pipe to the water pipe D) It increases the ampacity of the service conductors Correct Answer: A Rationale: The main bonding jumper (usually a green screw or metal strap) connects the neutral (grounded conductor) bus to the equipment grounding bus (panel enclosure). This creates the effective ground-fault current path. If a hot wire touches the metal case of an appliance, this bond ensures a low-impedance path back to the source, allowing the breaker to trip quickly rather than leaving the case energized.