Tamper-Resistant and Weather-Resistant Receptacle Rules
Why this matters
Swapping receptacles is the job a shop hands its newest apprentice, and it is where two quiet code rules get missed. A standard receptacle pulled off the truck for a garage wall, or an indoor-grade TR device screwed into a box on an exposed patio, both work on the day and both fail an inspection or a home-sale walk-through. Worse, the replacement rules in NEC 406.4(D) mean an old house does not get grandfathered once you touch the device: the receptacle you install has to meet today's requirements for that location. This card covers where tamper-resistant (TR) devices are required in a dwelling under 406.12, where weather-resistant (WR) devices are required under 406.9, how to read both marks off the face, and what a replacement inherits. Cite as NEC 2023 (2020 where the section moved), as adopted, local amendments checked.
Safety on every swap
A receptacle change is energized-equipment work until proven otherwise. Turn off the breaker, lock and tag it, and verify absence of voltage at the device with a CAT III or better meter proven on a known live source before and after the test (NFPA 70E Article 120, current edition; 29 CFR 1910.333(b)(2)). Test hot to neutral, hot to ground and neutral to ground, because a shared neutral or a second circuit in the same box will not show up on a single reading. When the new device is in and the plate is on, restore the breaker standing to the side of the panel, then check the device with a plug-in tester and, where GFCI protection applies, with its own test button.
Tamper-resistant: where a dwelling needs it
A TR receptacle has spring-loaded shutters behind the slots that open only when both blades push at once. A key or hairpin pushed into one slot meets plastic, not a contact.
The rule. In substance (406.12, check the current edition): in dwelling units, including attached and detached garages and accessory buildings to dwelling units, all 15 A and 20 A, 125 V and 250 V nonlocking receptacles are listed tamper-resistant. The 2020 edition added the 250 V devices, so a 6-20R for a garage compressor is in scope where 2020 or later is adopted. The same section reaches several other occupancies (guest rooms, child care, some educational, medical and assembly spaces); this card covers the dwelling.
What is not in scope:
- 30 A and 50 A receptacles. A 14-30R dryer receptacle or a 14-50R range or RV receptacle is outside the 15 A and 20 A scope.
- Locking receptacles. Twist-lock devices are excluded by the word "nonlocking."
The exceptions, each with its condition (in substance):
- More than 5.5 ft above the floor. A ceiling receptacle for a garage door opener qualifies; a receptacle at 5 ft for a wall TV does not.
- Part of a luminaire or appliance. The device built into a bath light bar is the luminaire maker's.
- A single receptacle, or a duplex for two appliances, in a dedicated space for appliances that are not easily moved in normal use and are cord-and-plug connected as 400.10 permits. The receptacle behind a refrigerator is the usual example.
- A nongrounding receptacle used as a replacement where 406.4(D)(2)(a) permits a two-prong device on an ungrounded circuit.
The practical answer. Most shops stock only TR devices in 15 A and 20 A, 125 V. Exceptions 1 and 3 then never have to be argued at a final, and the price difference between TR and standard grade is small.
Weather-resistant: damp versus wet
A WR receptacle is built with UV-stable plastics and corrosion-resistant metal parts for outdoor exposure. Where it is required depends on whether the location is damp or wet, and the two also take different covers.
The definitions (Article 100, in substance):
- Damp: partially protected from weather and subject to moderate moisture. A receptacle under a roofed open porch or under a canopy is damp.
- Wet: exposed to weather or subject to saturation. A receptacle on an open patio wall, a deck rail post, or anywhere rain can hit it directly is wet.
| Location | WR device required | Enclosure required |
|---|---|---|
| Damp (406.9(A)) | Yes, 15 A and 20 A, 125 V and 250 V nonlocking | Weatherproof when the receptacle is covered (plug out, lid closed) |
| Wet (406.9(B)(1)) | Yes, same scope | Weatherproof whether or not a plug is inserted: a listed outlet box hood identified "extra-duty" |
Why the wet cover is different. A cord left plugged into a patio receptacle through a storm is the normal case, not the abuse case. A flip lid that only seals with the plug out is a damp-location cover, and on a wet wall it is open every time the receptacle is in use. The extra-duty in-use hood seals around the cord.
The judgment call. Whether a covered porch is damp or wet depends on how far rain reaches under the roof. A receptacle 2 ft back under a 10 ft deep roof is damp; one at the edge of a shallow overhang on a windward wall gets wet. When in doubt, install the wet-location hood: it satisfies the damp requirement too, and the reverse is not true.
Reading the face
Both marks are molded into the device where they can be read after installation, usually on the face between or beside the slots:
- "TR" means listed tamper-resistant. Look into the slots too: you should see the shutter, not the brass contact.
- "WR" means listed weather-resistant.
- Both marks appear on combination devices, which is what an outdoor dwelling receptacle needs: TR because it is a 15 A or 20 A dwelling receptacle, WR because it is outdoors. Outdoor GFCI devices are commonly sold marked TR and WR together.
- No mark means a standard device. There is no way to upgrade one in place.
The mark is what the inspector checks, so it is what you check before the device goes into the box, not after the plate is on.
The replacement rule
406.4(D) is why old houses are not grandfathered on a swap. In substance, a receptacle replaced in a location where the current code requires a feature takes that feature:
- TR where 406.12 now requires it (406.4(D)(5)), except a nongrounding receptacle replaced by another nongrounding receptacle.
- WR where 406.9 now requires it (406.4(D)(6)).
- GFCI protection where 210.8 now requires it (406.4(D)(3)).
- AFCI protection where 210.12 now requires it, with the specific options 406.4(D)(4) allows.
Where GFCI and AFCI are required is owned by 'AFCI and GFCI by Location in a Dwelling'; replacing a two-prong device on an ungrounded circuit is owned by 'How to Replace a Two-Prong Receptacle on an Ungrounded Circuit'. The point here is that the TR and WR answers come from the same trigger: you replaced it, so it meets today's rule.
Worked example: nine receptacles in a 1978 house
The job. A one-family dwelling built in 1978, under the 2020 NEC as locally adopted. The owner wants nine worn receptacles replaced. None of the existing devices is TR or WR. The tech works the list before loading the van.
| # | Location | Device | TR | WR and cover | Reason |
|---|---|---|---|---|---|
| 1 | Bedroom wall | 15 A 125 V duplex | Yes | No | Dwelling, 15 A, 125 V |
| 2 | Kitchen countertop | 20 A 125 V | Yes | No | Dwelling, 20 A, 125 V |
| 3 | Bathroom | 20 A 125 V | Yes | No | Dwelling; WR is not required inside a bathroom in ordinary practice |
| 4 | Garage wall | 15 A 125 V | Yes | No | Garages are in 406.12's dwelling scope |
| 5 | Garage ceiling, opener, 9 ft up | 15 A 125 V single | No | No | Exception 1, more than 5.5 ft above the floor |
| 6 | Garage, compressor | 20 A 250 V, 6-20R | Yes | No | 2020 added 250 V devices |
| 7 | Laundry, dryer | 30 A, 14-30R | No | No | Outside the 15 A and 20 A scope |
| 8 | Front porch, 3 ft back under a 10 ft roof | 15 A 125 V | Yes | Yes, cover weatherproof with lid closed | Damp |
| 9 | Back patio, open wall | 15 A 125 V | Yes | Yes, extra-duty in-use hood | Wet |
The tally. TR on seven of nine (rows 1, 2, 3, 4, 6, 8 and 9); not on two (row 5 by the height exception, row 7 by amperage). WR on two of nine (rows 8 and 9), and the two take different covers. Every row also gets checked against the GFCI and AFCI card before the device is chosen, because a replacement inherits those too; under 2020, 210.8(A) reaches 250 V receptacles, so even row 7's dryer receptacle in a laundry area needs GFCI protection.
What the tally changes on the van. Seven required TR devices in three ratings (15 A 125 V, 20 A 125 V, 20 A 250 V), two of them TR and WR, plus a TR single for row 5 (the exception permits a standard device but does not require one), one extra-duty hood, one listed damp-location cover, and no standard-grade 15 A or 20 A stock at all. The 14-30R is ordered as is.
What moves the answer.
- The jurisdiction is still on the 2017 edition. Row 6, the 250 V compressor receptacle, drops out of the TR requirement there; the other rows hold.
- The opener receptacle is at 5 ft on the wall instead of on the ceiling. Exception 1 no longer applies; row 5 becomes TR.
- The porch roof is 3 ft deep and row 8 sits at its edge. The location reads as wet; row 8 takes the extra-duty hood.
What goes wrong after the swap
- An indoor TR device in an outdoor box. It carries TR and not WR, passes a plug-in tester, and fails both inspection and the first winter. Check for both marks on every outdoor device.
- A WR device under a damp-location lid on a wet wall. The device is right and the cover is wrong; the cord-in-use case is unprotected.
- A standard device in a wall box set at exactly 5 ft 6 in. The exception is measured from the floor, and 5 ft 6 in is 5.5 ft, not "more than 5.5 ft." Put the device above the line or use TR.
References
- NFPA 70, National Electrical Code, 406.4(D), 406.9, 406.12, Article 100 definitions of damp and wet locations (NEC 2023, 2020 where the section moved), as adopted by your jurisdiction.
- NFPA 70E, Article 120 (current edition); 29 CFR 1910.333(b)(2).
- See related: AFCI and GFCI by Location in a Dwelling; How to Replace a Two-Prong Receptacle on an Ungrounded Circuit.