NEC 2023 · checked by a second reviewer · November 7, 2026
NEC Article 210 Practice Questions (10 Free, With Answers)
Branch Circuits: 10 original questions on branch-circuit ratings, GFCI and AFCI protection and required receptacle outlets. Click an answer to see the explanation and the NEC section. No sign-up.
NEC Article 210 · 10 questions0 / 10 answered
Under NEC 2023, which 125-volt, 15- or 20-ampere receptacle in a dwelling unit requires GFCI protection?
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Correct answer: C. The dwelling GFCI list includes basements without limiting it to unfinished areas, so a finished basement recreation room is covered. Older editions applied the rule only to unfinished basements, which is why some people still skip finished ones. Bedrooms, hallways and living rooms are not on the list (unless a receptacle falls within 6 ft of a sink).Reference: NEC 210.8(A)
A homeowner wants a 240-volt, 50-ampere receptacle in an attached garage for a welder. It is fed from a single-phase 120/240-volt panel. Does it require GFCI protection under NEC 2023?
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Correct answer: D. In dwelling units, the GFCI requirement applies to receptacles from 125 V through 250 V supplied by single-phase circuits of 150 V or less to ground, and a 240-V circuit is 120 V to ground. For dwelling units there is no ampere cap, so a 50-A receptacle in a garage is covered. Limiting the rule to 15- and 20-A receptacles is the older rule people remember.Reference: NEC 210.8(A)
In a commercial office building, which 125-volt, 20-ampere receptacle requires GFCI protection?
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Correct answer: D. For other than dwelling units, rooftops are one of the listed locations where GFCI protection is required for these receptacles. Offices, conference rooms and dry interior corridors are not on the list unless another condition applies, such as being within 6 ft of a sink.Reference: NEC 210.8(B)
Under NEC 2023, which 120-volt, 20-ampere dwelling receptacle requires BOTH GFCI and AFCI protection?
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Correct answer: C. Kitchens appear on both lists: the GFCI list in 210.8(A) and the AFCI list in 210.12(A). Bathrooms, garages and outdoor receptacles need GFCI protection but are not among the AFCI locations, which is why the bathroom (a GFCI classic) is the tempting wrong pick.Reference: NEC 210.8(A); NEC 210.12(A)
An existing dwelling bedroom circuit has no AFCI protection. Which modification does NOT trigger the AFCI requirement for extended or modified branch circuits?
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Correct answer: A. When wiring in an AFCI area is modified, replaced or extended, AFCI protection is required, except for an extension of 6 ft or less that adds no outlets or devices other than splicing devices. Adding a receptacle, even only 2 ft away, adds an outlet, so the exception is lost regardless of the short length.Reference: NEC 210.12(D)
In a dwelling bedroom, a section of wall between two doorways measures 22 in. along the floor. For the receptacle spacing rule, is this section counted as wall space?
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Correct answer: B. For general-purpose dwelling receptacles, wall space is any unbroken section along the floor line 2 ft or wider, so a 22-in. section between doorways is not counted. The 12-in. figure belongs to the kitchen countertop rule, and 6 ft is the maximum distance to a receptacle, not the minimum width of wall space.Reference: NEC 210.52(A)(2)
A dwelling kitchen has a short wall countertop 14 in. wide between the range and the refrigerator. Is a receptacle outlet required to serve it?
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Correct answer: C. Countertop spaces separated by a range or refrigerator are treated as separate spaces, and each one that is 12 in. or wider must have a receptacle outlet. The 24-in. figure is the maximum distance from any point on the wall line to a receptacle, not the threshold that triggers the requirement.Reference: NEC 210.52(C)
For a one-family dwelling, which outdoor receptacle arrangement meets the minimum NEC requirement?
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Correct answer: D. A one-family dwelling needs at least one outdoor receptacle at the front and one at the back, each readily accessible from grade and no higher than 6 1/2 ft above grade. The 8-ft option is tempting but exceeds the height limit, and a single receptacle does not cover both front and back.Reference: NEC 210.52(E)(1)
Under NEC 2023, what is the minimum receptacle requirement for a new attached garage with two vehicle bays?
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Correct answer: B. The garage rule requires at least one receptacle outlet in each vehicle bay, mounted no higher than 5 1/2 ft above the floor. 'One for the whole garage' was the older requirement and is the tempting answer for anyone who learned an earlier edition.Reference: NEC 210.52(G)(1)
A 20-A, 120-V dwelling branch circuit supplies lighting and general-purpose receptacles. What is the largest fastened-in-place appliance (not a luminaire) that may also be connected to it?
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Correct answer: A. When a 15- or 20-A circuit also supplies lighting or cord-and-plug equipment, fastened-in-place utilization equipment may not exceed 50% of the circuit rating: 20 A x 0.50 = 10 A. The 16-A answer comes from the separate 80% limit for a single piece of cord-and-plug equipment not fastened in place.Reference: NEC 210.23(B)(2)
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