Receptacle Mounting Position Calculator

The face-up rule, by location

Countertop and work-surface receptacles

Two rules work together for a receptacle set into a countertop or work surface. 406.5(E) and 406.5(F) require the receptacle assembly to be listed for that application, and 406.5(G)(1) bars the face-up position unless the device is that listed assembly. Listed countertop and pop-up assemblies are built with the seals and drainage that let them sit in a work surface; an ordinary duplex dropped into a counter and turned face-up fails on both counts. A receptacle mounted vertically in the face of a countertop apron or backsplash is a different case and is not a face-up installation.

What changed in the 2020 edition

The 2017 edition of 406.5(G) carried only the countertop and work-surface sentence, with no subdivisions. The 2020 edition added 406.5(G)(2), prohibiting a receptacle installed in a face-up position in the area below a sink, and split the section into (G)(1) for countertops and work surfaces and (G)(2) for the below-sink area. The concern in both is the same: liquid spilled on a counter or dripping from a leak under a sink should not be able to settle into a receptacle. This tool uses the 2020 text; the 2023 edition reworded the countertop requirement again.

Flush, set back, and the 1/4-inch rule

Where a receptacle lands relative to the finished surface is governed by 406.5(A)/(B) and by 314.20, which 406.5 references. In a noncombustible wall or ceiling the front edge of the box may be set back no more than 1/4 in (6 mm) from the finished surface; in combustible material the box must be flush with or project from the surface. Either way, 406.5(A)/(B) require the mounting yoke to be held rigidly: at the finished surface when the box is set back (the box ears or shims carry it), or against the box or a raised cover when the box is flush. A box set too deep is corrected with a listed box extender rather than by letting the device float on long screws.

A note on the lettering: published summaries of the 2020 edition disagree on whether the set-back case is 406.5(A) or 406.5(B) and which letter is the flush case. The requirement itself is not in dispute, so this tool states the yoke rule by the physical box condition and cites 406.5(A)/(B) as a pair rather than pinning a single letter.

Worked example: a kitchen island

Say the plan calls for a receptacle flush in the top of a kitchen island so a countertop appliance can plug in from above. A standard duplex set face-up in the countertop is a 406.5(G)(1) violation. The compliant options are a receptacle assembly listed for countertop use (which may be face-up because it is listed for it) or a receptacle mounted in the vertical face of the island, not the horizontal top. Put the same ordinary receptacle face-up in the cabinet floor under the sink and 406.5(G)(2) prohibits it outright, with no listed exception.

Common mistakes

• Face-up in a counter with an ordinary device. Only a listed countertop/work-surface assembly may be installed face-up there (406.5(G)(1)).
• Face-up under a sink. 406.5(G)(2) bars it; this is a 2020 addition that older habits miss, and there is no listed exception.
• Letting a set-back box exceed 1/4 in. In noncombustible walls the box front edge cannot be set back more than 1/4 in; use a box extender (314.20).
• A loose device on long screws. The yoke must be held rigidly at or against the finished surface (406.5(A)/(B)), not floating in the opening.
• Confusing position with where receptacles go. This tool checks mounting position, not where receptacles are required (210.52) or their GFCI/AFCI protection (210.8/210.12).

Frequently asked questions

Can a receptacle be installed face up?

Under NEC 2020 406.5(G), a receptacle shall not be installed in a face-up position in or on a countertop or work surface unless it is part of an assembly listed for that application (406.5(G)(1)), and shall not be installed face-up in the area below a sink (406.5(G)(2), new in the 2020 edition). In a general wall location 406.5(G) does not restrict the orientation, though floor receptacles have their own listing and cover rules.

Can you put a receptacle face up in a kitchen countertop?

Not with an ordinary device. 406.5(G)(1) prohibits a receptacle installed face-up in or on a countertop or work surface unless it is a receptacle assembly listed for countertop or work-surface use. Listed flush or pop-up countertop assemblies are built with the sealing and drainage features that let them face up; a standard duplex set face-up in the counter is a violation.

Why can a receptacle not be installed face up under a sink?

The 2020 NEC added 406.5(G)(2), which prohibits a receptacle from being installed in a face-up position in the area below a sink. A face-up receptacle in that location can collect dripping water or debris from a leak, so the rule requires the receptacle face to be oriented so liquid cannot settle into it. Unlike the countertop rule, there is no listed-assembly exception for the below-sink location.

How far can an outlet box be set back from the finished wall?

NEC 314.20, referenced by 406.5(A)/(B), allows the front edge of a box in a noncombustible wall or ceiling (such as drywall or plaster) to be set back no more than 6 mm (1/4 in.) from the finished surface. In combustible material (such as exposed wood) the box must be flush with the finished surface or project from it. A box set too far back is brought forward with a listed box extender or extension ring.

Does a receptacle have to be flush with the faceplate?

NEC 406.5(D) governs the position of receptacle faces: they must be flush with or project from faceplates of insulating material, and must project from metal faceplates. 406.5(A)/(B) separately require the mounting yoke to be held rigidly at the finished surface when the box is set back, or against the box or raised cover when the box is flush, so the device is not loose.

Does this calculator use the 2020 or 2023 NEC?

It implements the NEC 2020 text of 406.5. The face-up rule moved across editions: the 2017 edition had only the countertop sentence under 406.5(G), the 2020 edition added 406.5(G)(2) for the area below a sink and split the subsection into (G)(1) and (G)(2), and the 2023 edition reworded the countertop requirement again. Always verify against the edition your jurisdiction has adopted.

Related calculators

• Receptacle Replacement Requirement Calculator: what a replacement receptacle must be under NEC 406.4(D), including GFCI, AFCI, and tamper-resistance carried onto the new device.
• Tamper-Resistant & Weather-Resistant Receptacle Calculator: where a receptacle must be tamper-resistant (406.12) or weather-resistant (406.9).
• Dwelling Required Receptacle Outlets Calculator: where a dwelling receptacle outlet is required and the minimum count per NEC 210.52.
• Receptacle Rating & Branch-Circuit Load Calculator: the receptacle rating permitted on a branch circuit and the maximum cord-and-plug load per NEC 210.21(B).