Receptacle Replacement Requirement Calculator

The grounding question comes first (406.4(D)(1) and (D)(2))

The single branch that decides a receptacle replacement is whether the outlet box has an equipment grounding conductor. With one, the replacement is a grounding-type receptacle and its grounding terminal is connected to that conductor (406.4(D)(1)). With none, which is the common situation in older two-wire wiring, the replacement must be one of three options.

When a GFCI is used for a no-ground replacement, an equipment grounding conductor must not be run from it to any outlet it supplies (406.4(D)(2)(b)). The device is protecting against ground faults without a real ground path, so the markings warn the next person that the three-prong opening does not mean an equipment ground is present.

The protections carry onto the replacement (406.4(D)(3) through (D)(6))

406.4(D) has no grandfathering. If the location requires a protection under the currently adopted Code, the replacement device has to provide it, even when the receptacle you are removing predated the rule. These four requirements are independent and stack on top of the grounding answer.

The one relief is in 406.4(D)(5): a nongrounding receptacle replaced with another nongrounding receptacle does not have to be tamper-resistant. As soon as you upgrade to a grounding-type or GFCI-type device at a tamper-resistant location, the tamper-resistant requirement applies again.

Worked example: a kitchen counter receptacle

You are replacing a worn receptacle above a kitchen counter. The box has an equipment grounding conductor, so 406.4(D)(1) requires a grounding-type receptacle connected to it. A kitchen counter outlet is a 210.8(A) GFCI location, so 406.4(D)(3) requires the replacement to be GFCI-protected, and because it is a dwelling, 406.4(D)(5) requires it to be tamper-resistant. The correct device is a listed tamper-resistant GFCI receptacle (or a tamper-resistant receptacle on a GFCI-protected circuit). Move the same job to a 1960s bedroom with two-wire cable and no ground, and the answer changes to the 406.4(D)(2) options: a two-prong replacement, a GFCI marked "No Equipment Ground," or a grounding-type downstream of a GFCI marked "GFCI Protected" and "No Equipment Ground," with AFCI protection added per 406.4(D)(4) if the bedroom circuit requires it.

Common mistakes

• Assuming a straight swap carries no new requirements. There is no grandfathering under 406.4(D); the replacement must meet the current rule for the location.
• Putting a three-prong receptacle on an ungrounded box with nothing else. With no equipment ground, a grounding-type device is only permitted downstream of a GFCI and marked accordingly (406.4(D)(2)(c)).
• Running a ground wire from a no-ground GFCI to its downstream outlets. 406.4(D)(2)(b) prohibits it; the GFCI is the protection, not a real ground.
• Skipping the "No Equipment Ground" marking. It is required on the no-ground GFCI options so the next person is not misled by the three-prong face.
• Forgetting tamper-resistant on a grounding-type upgrade. The TR relief is only for a nongrounding-to-nongrounding swap.

Frequently asked questions

Do I need a GFCI to replace an outlet?

Under NEC 406.4(D)(3), you must provide GFCI protection on the replacement if the outlet is at a location that the currently adopted Code requires to be GFCI-protected (210.8), for example a kitchen, bathroom, garage, or outdoor receptacle, even if the original device was not GFCI-protected. Where the location does not require GFCI protection, a replacement does not have to be GFCI just because you are swapping the device. Separately, if there is no equipment grounding conductor in the box, 406.4(D)(2)(b) lets you use a GFCI-type receptacle marked "No Equipment Ground" as one way to replace a two-prong receptacle.

Can I replace a two-prong receptacle with a three-prong one?

Only with a path to ground or with GFCI protection. If the box has an equipment grounding conductor, 406.4(D)(1) requires a grounding-type (three-prong) receptacle connected to it. If the box has no equipment grounding conductor, NEC 406.4(D)(2) gives three options: a nongrounding (two-prong) replacement; a GFCI-type receptacle marked "No Equipment Ground"; or a grounding-type receptacle fed downstream of a GFCI and marked "GFCI Protected" and "No Equipment Ground."

Does a replacement receptacle have to be tamper-resistant?

NEC 406.4(D)(5) requires a listed tamper-resistant receptacle wherever a replacement is made at an outlet that is required to be tamper-resistant under 406.12, such as in a dwelling unit. The one relief is a nongrounding receptacle replaced with another nongrounding receptacle, which does not have to be tamper-resistant. Upgrading to a grounding-type or GFCI-type device at a tamper-resistant location brings the requirement back.

Is there grandfathering when I replace a receptacle?

No. NEC 406.4(D) requires a replacement receptacle to meet the protection that applies to its location under the currently adopted Code, even when the original device predated that rule. Swapping the receptacle is the trigger: GFCI (210.8), AFCI (210.12), tamper-resistant (406.12), and weather-resistant (406.9) requirements all attach to the new device where the location calls for them.

What must an AFCI replacement receptacle be?

NEC 406.4(D)(4) requires arc-fault protection on a replacement where the location is required to be AFCI-protected under 210.12. It is satisfied by a listed outlet branch-circuit (OBC) type AFCI receptacle, a receptacle installed downstream of a listed OBC AFCI receptacle, or a receptacle protected by a listed combination-type AFCI circuit breaker. Limited exceptions exist in the Code; confirm them against the adopted edition before relying on one.

Related calculators

• GFCI Breaker Sizing Calculator: where dwelling and non-dwelling receptacles need ground-fault protection per NEC 210.8.
• AFCI Requirement & Breaker Sizing Calculator: where dwelling branch circuits need arc-fault protection per NEC 210.12.
• Tamper-Resistant & Weather-Resistant Receptacle Calculator: where a receptacle must be TR or WR per NEC 406.12 and 406.9.
• Dwelling Receptacle Spacing Calculator: the 210.52 wall and countertop receptacle placement rules.