NEC - National Electrical Code Branch Circuit Requirements Questions and Answers

Question 1

According to NEC Article 210, which of the following locations in a dwelling unit requires Arc-Fault Circuit-Interrupter (AFCI) protection for all 120-volt, single-phase, 15- and 20-ampere branch circuits supplying outlets and devices?

Accepted Answer

Kitchens

Answer

NEC Section 210.12(A) mandates AFCI protection for 120-volt, single-phase, 15- and 20-ampere branch circuits in various dwelling unit locations, including kitchens. While bathrooms, garages, and basements have specific GFCI requirements, the comprehensive AFCI requirement applies to kitchens along with other specified living areas.

Question 2

An electrician is wiring a new single-family home. What is the minimum requirement for the branch circuit supplying the receptacle outlets in the laundry area?

Accepted Answer

One 20A, 120V branch circuit dedicated solely to the laundry receptacle outlet(s).

Answer

NEC Section 210.11(C)(2) requires at least one 20-ampere branch circuit to be provided for the laundry receptacle outlet(s) required by 210.52(F). This circuit is prohibited from supplying any other outlets, such as lighting or receptacles in other rooms.

Question 3

A multi-outlet 20A branch circuit supplies both lighting outlets and fastened-in-place utilization equipment. What is the maximum permissible total rating of the fastened-in-place equipment?

Accepted Answer

10 amperes (50%)

Answer

According to NEC Section 210.23(A)(2), on a branch circuit supplying a combination of lighting units, cord-and-plug-connected utilization equipment not fastened in place, and fastened-in-place utilization equipment, the total rating of the fastened-in-place utilization equipment is not permitted to exceed 50% of the branch-circuit rating. For a 20A circuit, this is 10A.

Question 4

In a dwelling unit bathroom, a 20-ampere, 120-volt branch circuit is installed to supply the required receptacle outlet at the sink. According to NEC 210.11(C)(3), what else can this specific circuit supply?

Accepted Answer

Outlets for other equipment within the same bathroom, but only if the circuit supplies a single bathroom.

Answer

NEC 210.11(C)(3) requires at least one 20A, 120V branch circuit for bathroom receptacle outlet(s), and this circuit shall have no other outlets. However, an important exception exists: if the 20-ampere circuit supplies only a single bathroom, it is permitted to supply other equipment outlets (like a fan or light) within that same bathroom.

Question 5

Which of the following locations in a dwelling unit requires GFCI protection for all 125-volt through 250-volt receptacles supplied by single-phase branch circuits rated 150 volts or less to ground?

Accepted Answer

Basements (finished or unfinished)

Answer

NEC Section 210.8(A)(5) was revised to require GFCI protection for all 125-volt through 250-volt receptacles in basements, regardless of whether they are finished or unfinished. This is a broader requirement than those for hallways, bedrooms, or closets, which primarily fall under AFCI protection rules.

NEC Practice Test

NEC Practice Test

NEC - National Electrical Code Branch Circuit Requirements Questions and Answers