Kitchen sink wall at rough-in
What's wrong here?
- The cable between the two boxes is too small for this circuit
- Countertop receptacles must be on 15 A circuits
- NM cable may not pass through bored holes in exterior wall studs
- Nothing. This installation is compliant
Show the answer and the code reference
The answer
A white-sheathed 14 AWG NM cable links two receptacle boxes on a 20 A small-appliance branch circuit that is otherwise run in yellow 12 AWG.
Correct choice: 1. The cable between the two boxes is too small for this circuit
Kitchen countertop receptacles must be served by 20 A small-appliance branch circuits (210.11(C)(1)), so every conductor in the circuit has to be good for 20 A. 240.4(D)(3) caps overcurrent protection for 14 AWG copper at 15 A, and NM cable is held to the 60°C ampacity of 15 A for 14 AWG (334.80, Table 310.16), so a toaster and a kettle on that counter can push the 14 AWG section past its rating without tripping the 20 A breaker. The sheath is the giveaway: by industry convention white NM-B is 14 AWG and yellow is 12 AWG, and the printed legend confirms it. One short scrap of the wrong cable downgrades the entire circuit.
How to fix it
Pull out the 14/2 and replace it with 12/2 NM-B between the two boxes so the whole circuit is 12 AWG copper on its 20 A breaker. Do not solve it by dropping the breaker to 15 A; that violates 210.11(C)(1).
Code references
NEC 2023 240.4(D)(3) — Small Conductors — 14 AWG Copper
Unless specifically permitted elsewhere, the overcurrent protection for 14 AWG copper conductors may not exceed 15 A after any correction and adjustment factors are applied.
Drills citing 240.4(D)(3)NEC 2023 210.11(C)(1) — Small-Appliance Branch Circuits
In each dwelling unit, two or more 20 A small-appliance branch circuits must be provided for the receptacle outlets required by 210.52(B), which include the kitchen countertop receptacles.
Drills citing 210.11(C)(1)NEC 2023 Table 310.16 — Ampacities of Insulated Conductors with Not More Than Three Current-Carrying Conductors in Raceway, Cable, or Earth (Directly Buried)
Lists 14 AWG copper at 15 A in the 60°C column, the column NM cable ampacity is limited to under 334.80.
Drills citing Table 310.16
2026 NEC:same rule and number. 14 AWG copper is still limited to 15 A overcurrent protection in 240.4(D)(3); the 2026 revision to 240.4 retitled and reorganized parts of the section for usability, which the panel described as having no technical change. Confidence: medium
Minnesota
Minnesota adopted the 2023 NEC without amendment as the Minnesota Electrical Code (Minn. Rules 1315.0200; Minn. Stat. 326B.35), effective July 1, 2023, so 240.4(D), 210.11(C), and Table 310.16 apply as published. That edition governs permits filed through Aug. 16, 2026; permits filed on or after Aug. 17, 2026 fall under the 2026 NEC; see the 2026 NEC note on this drill for how the cited section fares there.
How Minnesota adopts the NECWhy the other choices are wrong
- Countertop receptacles must be on 15 A circuits. It is the other way around: 210.11(C)(1) requires at least two 20 A small-appliance branch circuits for the kitchen countertop receptacles.
- NM cable may not pass through bored holes in exterior wall studs. Bored holes are fine; 300.4(A)(1) only requires the hole edge to be at least 1-1/4 in from the stud face, or a steel plate if it is closer.
- Nothing. This installation is compliant. The white sheath is 14 AWG. On a 20 A small-appliance circuit, 14 AWG copper is overloaded and unprotected; 240.4(D)(3) caps it at 15 A.