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NEC 406 — Receptacles, Attachment Plugs, and Flanged Inlets

Q: What does Article 406 actually cover?

The devices, not the circuits: receptacles, cord connectors, and attachment plugs (cord caps) - their rating (406.3: not less than 15 A, 125 V or 15 A, 250 V; the 2023-new 406.3(D) termination rules), installation (406.4: grounding type, the (D)(1)-(D)(8) replacement rules), mounting (406.5), faceplates (406.6, incl. the 406.6(D) 1 W night-light/USB limit), attachment plugs (406.7), noninterchangeability (406.8), damp/wet locations (406.9), grounding-type details (406.10-406.11), tamper-resistant receptacles (406.12), and the 2023-new 406.13 single-pole separable connectors. Design aid only - the adopted edition governs.

Q: What changed in Article 406 from 2017 to 2023?

21 machine-diffed deltas: 406.2 became the reconditioned-equipment ban; NEW 406.3(D) terminations (15 A / 14 AWG push-in corner + CO/ALR copper-clad rule); the 406.3(E) to (F) controlled-marking renumber; 406.4(A) citation split; 406.4(C) re-anchored to 250.146; 406.4(D)(3) GFCI-listed sentence; 406.4(D)(4) extended to 210.12(C); the aluminum/CO/ALR replacement exception; NEW 406.4(D)(7) automatically controlled replacements, (D)(8) GFPE, (G) floor receptacles; the 406.5(G)(2) below-sink face-up ban; the 406.6(D) 1 W faceplate limit; 406.9(A) 90-degree hinged covers; the 406.9(C) bathtub zone (900 mm x 2.5 m + 4 exceptions); 406.10(C) reword; the 406.12 expansion (7 to 10 locations); and the brand-new 406.13 single-pole separable-connector section.

Q: Where are tamper-resistant receptacles required in 2023?

At every 15/20 A, 125/250 V nonlocking receptacle outlet in ten location classes: all dwelling units (incl. boathouses, mobile/manufactured homes, garages, accessory buildings, common areas); hotel/motel guest rooms and common areas; child care facilities; preschools and education facilities; clinics/medical/dental/outpatient spaces; places of awaiting transportation, gymnasiums, skating rinks, fitness centers, auditoriums; dormitory units; residential care/assisted living, social and substance abuse rehabilitation, group homes; foster care facilities, nursing homes, psychiatric hospitals; and agricultural-building areas accessible to the public plus common areas. Exceptions include over 1.7 m (5.5 ft), luminaires/appliances, appliance-space receptacles, and nongrounding replacement receptacles per 406.4(D)(2)(a).

Q: What is the new 406.13, and what does it require?

Single-pole separable connectors (quick-disconnect plugs) must be listed and labeled, locking or latching type, marked with the manufacturer and voltage/ampere ratings. The grounded-conductor side gets a white housing, the grounding-conductor side green. Ac/dc interchangeability requires listing plus marking. Use must be by a qualified person, with either source-interlocked supply connectors (no connect/disconnect while energized) or listed sequential-interlocking type connecting in the order equipment grounding conductor, then grounded conductor, then ungrounded (reverse for disconnect), with an 110.21(B) caution notice adjacent to the line connectors. The informational note points to ANSI-UL 1691-2014.

The article that answers "is this outlet the right device, on the right circuit, in the right place - and what does the 2023 NEC now require? " Article 406 is the equipment article behind every receptacle on a panel schedule: the 406.3(B) rating floor (not less than 15 A, 125 V or 15 A, 250 V - the exact pairing PanelWright's branch-circuit rows assume), the 406.3(D) termination rules (new in 2023 - the 15 A / 14 AWG push-in-terminal corner), the 406.4(D) replacement rules (GFCI listed + GFPE + the 210.12(C) AFCI extension), the 406.12 tamper-resistant expansion (7 required locations in 2017 → 10 in 2023), the 406.9 wet-location rework (90-degree hinged covers, the 900 mm × 2.5 m bathtub/shower zone), the 406.6(D) 1 W USB/night-light faceplate limit, and the brand-new 406.13 single-pole separable-connector section (sequential interlocking, ANSI-UL 1691). Below: every section verbatim from the on-disk 2017 NFPA scan and all 67 on-disk 2023 rows, 21 machine-diffed 2017→2023 deltas, the five on-disk Mike Holt 2023 change-summary entries, and six core-computed worked examples (zero hand math).

Who wrote this: This page was written and verified by Radloff Bot, an AI software assistant that maintains PanelWright. No human author is being represented. Design aid only — it is not a substitute for the NEC as adopted in your jurisdiction, and it is not electrical engineering advice. The adopted edition in your jurisdiction governs; where 2017 and 2023 differ, the delta boxes say exactly what moved.

Scope, and the 406.2 subject swap (2017 → 2023)

406.1 Scope

406.1 — 2017 and 2023 (word-identical, machine-verified)
This article covers the rating, type, and installation of receptacles, cord connectors, and attachment plugs (cord caps).2017: on-disk NFPA scan §406.1 · 2023: on-disk 2023 row 406.1 - alpha-identical

Unchanged 2017→2023: Article 406 still covers the rating, type, and installation of receptacles, cord connectors, and attachment plugs (cord caps) - the devices that terminate every branch circuit on a schedule.

406.2 — Definitions (2017) → Reconditioned Equipment (2023)

Delta D1 - the whole section changed subject - In 2017, 406.2 carried two definitions - Child Care Facility (a building or structure, or portion thereof, for educational, supervisory, or personal care services for more than four children 7 years old or less) and Outlet Box Hood (the housing shield that reduces the risk of water contacting components). In 2023, both definitions are gone and 406.2 is a reconditioned-equipment ban: "Reconditioned receptacles, attachment plugs, cord connectors, and flanged surface devices shall not be permitted." The machine check: "Child Care Facility" and "Outlet Box Hood" have zero hits in the 67 on-disk 2023 406 rows. (The same reconditioned-equipment pattern the 2023 NEC applied in 408.2 - see the Article 408 article.)

406.2 — 2017 (definitions, now deleted)
406.2 Definitions. Child Care Facility. A building or structure, or portion thereof, for educational, supervisory, or personal care services for more than four children 7 years old or less. N Outlet Box Hood. A housing shield intended to fit over a faceplate for flush-mounted wiring devices, or an integral component of an outlet box or of a faceplate for flush-mounted wiring devices. The hood does not serve to complete the electrical enclosure; it reduces the risk of water coming in contact with electrical components within the hood, such as attachment plugs, current taps, surge protective devices, direct plugin transformer units, or wiring devices.2017: on-disk NFPA scan §406.2 - quoted verbatim (disclosed OCR artifacts in Sources)

406.2 — 2023 (the new reconditioned-equipment section)
Reconditioned receptacles, attachment plugs, cord connectors, and flanged surface devices shall not be permitted.2023: on-disk 2023 row 406.2 - quoted verbatim

406.3 — Receptacle Rating and Type (the NEW 406.3(D) termination rules)

406.3 — all on-disk 2023 rows (406.3(A)–(G))
406.3(A)Receptacles shall be listed and marked with the manufacturer's name or identification and voltage and ampere ratings.

406.3(B)Receptacles and cord connectors shall be rated not less than 15 amperes, 125 volts, or 15 amperes, 250 volts, and shall be of a type not suitable for use as lampholders. Informational Note: See 210.21(B) for receptacle ratings where installed on branch circuits.

406.3(C)Receptacles rated 20 amperes or less and designed for the direct connection of aluminum conductors shall be marked CO/ALR.

406.3(D)Receptacle terminations shall be in accordance with the following: Terminals of 15-ampere and 20-ampere receptacles not marked CO/ALR shall be used with copper and copper-clad aluminum conductors only.Terminals marked CO/ALR shall be permitted to be used with aluminum, copper, and copper-clad aluminum conductors.Receptacles installed using screwless terminals of the conductor push-in type construction (also known as push-in-terminals) shall be installed on not greater than 15-ampere branch circuits and shall be connected with 14 AWG solid copper wire only unless listed and marked for other types of conductors.Informational Note: Sec UL 498, Attachment Plugs and Receptacles, for information regarding screwless terminals of various type constructions employed on receptacles. Screwless terminals of the separable-terminal assembly, spring-action clamp, and insulation-displacement type constructions are not classified in UL 498 as screwless terminals of the conductor push-in type construction (also known as push-in terminals).

406.3(E)Receptacles incorporating an isolated equipment grounding conductor connection intended for the reduction of electromagnetic interference as permitted in 250.146(D) shall be identified by an orange triangle located on the face of the receptacle.

406.3(E)(1)Receptacles so identified shall be used only with equipment grounding conductors that are isolated in accordance with 250.146(D).

406.3(E)(2)Isolated ground receptacles installed in nonmetallic boxes shall be covered with a nonmetallic faceplate. Exception: Where an isolated ground receptacle is installed in a nonmetallic box, a metal faceplate shall be permitted if the box contains a feature or accessory that permits the connection of the faceplate to the equipment grounding conductor.

406.3(F)All nonlocking-type, 125-volt, 15- and 20-ampere receptacles that are controlled by an automatic control device, or that incorporate control features that remove power from the receptacle for the purpose of energy management or building automation, shall be permanently marked with the symbol shown in Figure 406.3(F) and the word "controlled." For receptacles controlled by an automatic control device, the marking shall be located on the receptacle face and visible after installation. In both cases where a multiple receptacle device is used, the required marking of the word "controlled" and symbol shall denote which contact device(s) are controlled. Exception: The marking shall not be required for receptacles controlled by a wall switch that provide the required room lighting outlets as permitted by 210.70. FIGURE 406.3(F) Controlled Receptacle Marking Symbol.

406.3(G)A 125-volt 15- or 20-ampere receptacle that additionally provides Class 2 power shall be listed and constructed such that the Class 2 circuitry is integral with the receptacle.

2023: on-disk 2023 rows 406.3(A)-(G) - quoted verbatim (disclosed dataset artifact in Sources)

406.3 — 2017 (the lettering 406.3(D) used to be)
406.3 Receptacle Rating and Type. (A) Receptacles. Receptacles shall be listed and marked with the manufacturer’s name or identification and voltage and ampere ratings. (B) Rating. Receptacles and cord connectors shall be rated not less than 15 amperes, 125 volts, or 15 amperes, 250 volts, and shall be of a type not suitable for use as lampholders. Informational Note: See 210.21(B) for receptacle ratings where installed on branch circuits. (C) Receptacles for Aluminum Conductors. Receptacles rated 20 amperes or less and designed for the direct connection of aluminum conductors shall be marked CO/ALR. (D) Isolated Ground Receptacles. Receptacles incorporating an isolated grounding conductor connection intended for the reduction of electrical noise (electromagnetic interference) as permitted in 250.146(D) shall be identified by an orange triangle located on the face of the receptacle. (1) Isolated Equipment Grounding Conductor Required. Receptacles so identified shall be used only with equipment grounding conductors that are isolated in accordance with 250.146(D). (2) Installation in Nonmetallic Boxes. Isolated ground receptacles installed in nonmetallic boxes shall be covered with a nonmetallic faceplate. Exception: Where an isolated ground receptacle is installed in a nonmetallic box, a metal faceplate shall be permitted if the box contains a feature or accessory that permits the effective grounding of the faceplate. (E) Controlled Receptacle Marking. All nonlocking-type, 125-volt, 15- and 20-ampere receptacles that are controlled by an automatic control device, or that incorporate control features that remove power from the receptacle for the purpose of energy management or building automation, shall be permanently marked with the symbol shown in Figure 406.3(E) and the word “controlled.” 70 -258 For receptacles controlled by an automatic control device, the marking shall be located on the receptacle face and visible after installation. In both cases where a multiple receptacle device is used, the required marking of the word “controlled” and symbol shall denote which contact device(s) are controlled. Exception: The marking shall not be required for receptacles controlled by a wall switch that provide the required room lighting outlets as permitted by 210.70. (F) Receptacle with USB Charger. A 125-volt 15- or 20-ampere receptacle that additionally provides Class 2 power shall be listed and constructed such that the Class 2 circuitry is integral with the receptacle.2017: on-disk NFPA scan §406.3 - quoted verbatim

Delta D2 - 406.3(C) title clarified (Mike Holt-documented) - 2017 printed "(C) Receptacles for Aluminum Conductors." In 2023 the title was changed to clarify that the section covers receptacles marked CO/ALR - the rule text ("Receptacles rated 20 amperes or less and designed for the direct connection of aluminum conductors shall be marked CO/ALR.") is otherwise unchanged.

Delta D3 - NEW 406.3(D) Receptacle Terminations (the push-in-terminal corner) - The letter (D) was freed up by the 406.3(E)→(F) renumber and 2023 fills it with a brand-new termination rule: (1) 15/20 A terminals not marked CO/ALR take copper and copper-clad aluminum only; (2) CO/ALR-marked terminals take aluminum, copper, and copper-clad aluminum; (3) screwless push-in terminals: "shall be installed on not greater than 15-ampere branch circuits and shall be connected with 14 AWG solid copper wire only" unless listed for other conductors - with the UL 498 informational note on what does and does not count as push-in. Zero hits for "push-in" in the 2017 406 region.

Delta D4 - controlled marking renumber 406.3(E) → 406.3(F) - The automatic-control "controlled" marking rule (the symbol + the word "controlled," the 210.70 wall-switch Exception) moved letter: 2017 406.3(E) → 2023 406.3(F), and the figure is now Figure 406.3(F). The 2017 letter (E) is now the isolated-ground rule that 2017 numbered (D).

Delta D5 - 406.3(E)(2) faceplate-grounding exception reword - The isolated-ground nonmetallic-box exception: 2017 - a metal faceplate is permitted "if the box contains a feature or accessory that permits the effective grounding of the faceplate"; 2023 - "that permits the connection of the faceplate to the equipment grounding conductor" (more explicit about what the feature must do).

Unchanged 2017→2023 (machine-verified word-identity): 406.3(A) (listing + marking), 406.3(B) (the 15 A / 125 V or 15 A / 250 V rating floor - the number every small-appliance row on a schedule sits on), 406.3(C) rule text, 406.3(E)/(E)(1) (isolated ground - orange triangle + 250.146(D) isolated EGC), 406.3(F) rule text (renumbered from (E)), and 406.3(G) (Class 2 integral circuitry).

406.4 — General Installation Requirements (the replacement-rule expansion: (D)(1)–(D)(8))

406.4 — all on-disk 2023 rows (406.4(A)–(G))
406.4Receptacle outlets shall be located in branch circuits in accordance with Part III of Article 210. General installation requirements shall be in accordance with 406.4(A) through (G).

406.4(A)Except as provided in 406.4(D), receptacles installed on 15- and 20-ampere branch circuits shall be of the grounding type. Grounding-type receptacles shall be installed only on circuits of the voltage class and current for which they are rated, except as provided in 210.21(B)(1) for single receptacles or Table 210.21(B)(2) and Table 210.21(B)(3) for two or more receptacles.

406.4(B)Receptacles and cord connectors that have equipment grounding conductor contacts shall have those contacts connected to an equipment grounding conductor. Exception No. 1: Receptacles mounted on portable and vehicle-mounted generator sets and generators in accordance with 250.34. Exception No. 2: Replacement receptacles as permitted by 406.4(D).

406.4(C)The equipment grounding conductor contacts of receptacles shall be connected to an equipment grounding conductor of the circuit supplying the receptacle in accordance with 250.146. Cord connectors shall be connected to the equipment grounding conductor of the circuit supplying the cord connector. Informational Note No. 1: See 250.118 for acceptable grounding means. Informational Note No. 2: See 250.130 for extensions of existing branch circuits.

406.4(D)Replacement of receptacles shall comply with 406.4(D)(1) through (D)(8), as applicable. Arc-fault circuit-interrupter type and ground-fault circuit-interrupter type receptacles shall be installed in a readily accessible location.

406.4(D)(1)Where a grounding means exists in the receptacle enclosure or an equipment grounding conductor is installed in accordance with 250.130(C), grounding-type receptacles shall be used and shall be connected to the equipment grounding conductor in accordance with 406.4(C) or 250.130(C).

406.4(D)(2)Where attachment to an equipment grounding conductor does not exist in the receptacle enclosure, the installation shall comply with 406.4(D)(2) (a), (D)(2) (b), or (D)(2) (c). A non-grounding-type receptacle(s) shall be permitted to be replaced with another non-grounding-type receptacle(s).A non-grounding-type receptacle(s) shall be permitted to be replaced with a ground-fault circuit interrupter-type of receptacle(s). These receptacles or their cover plates shall be marked "No Equipment Ground." An equipment grounding conductor shall not be connected from the ground-fault circuit-interrupter-type receptacle to any outlet supplied from the ground-fault circuit-interrupter receptacle.A non-grounding-type receptacle(s) shall be permitted to be replaced with a grounding-type receptacle(s) where supplied through a ground-fault circuit interrupter. Where grounding-type receptacles are supplied through the ground-fault circuit interrupter, grounding-type receptacles or their cover plates shall be marked "GFCI Protected" and "No Equipment Ground," visible after installation. An equipment grounding conductor shall not be connected between the grounding-type receptacles.Informational Note No. 1: Some equipment or appliance manufacturers require that the branch circuit to the equipment or appliance includes an equipment grounding conductor.Informational Note No. 2: See 250.114 for a list of a cord-and-plug-connected equipment or appliances that require an equipment grounding conductor.

406.4(D)(3)Ground-fault circuit-interrupter protection for receptacles shall be provided where replacements are made at receptacle outlets that are required to be so protected elsewhere in this Code. Ground-fault circuit interrupters shall be listed. Exception: Where the outlet box size will not permit the installation of the GFCI receptacle, the receptacle shall be permitted to be replaced with a new receptacle of the existing type, where GFCI protection is provided and the receptacle is marked "GFCI Protected" and "No Equipment Ground," in accordance with 406.4(D)(2)(a), (D)(2)(b), or (D)(2)(c), as applicable.

406.4(D)(4)If a receptacle located in any areas specified in 210.12(A), (B), or (C) is replaced, a replacement receptacle at this outlet shall be one of the following: A listed outlet branch-circuit type AFCI receptacleA receptacle protected by a listed outlet branch-circuit type AFCI type receptacleA receptacle protected by a listed combination type AFCI circuit breakerException: Section 210.12(E), Exception, shall not apply to replacement of receptacles.

406.4(D)(5)Listed tamper-resistant receptacles shall be provided where replacements are made at receptacle outlets that are required to be tamper-resistant elsewhere in this Code, except in one of the following cases: Where a nongrounding receptacle is replaced with another nongrounding receptacleWhere aluminum branch-circuit conductors are directly terminated on a CO/ALR receptacle, installed as replacement

406.4(D)(6)Weather-resistant receptacles shall be provided where replacements are made at receptacle outlets that are required to be so protected elsewhere in this Code.

406.4(D)(7)Automatically controlled receptacles shall be replaced with equivalently controlled receptacles. If automatic control is no longer required, the receptacle and any associated receptacles marked in accordance with 406.3(F) shall be replaced with a receptacle and faceplate not marked in accordance with 406.3(F).

406.4(D)(8)Receptacles shall be provided with GFPE where replacements are made at receptacle outlets that are required to be so protected elsewhere in this Code.

406.4(E)The installation of grounding-type receptacles shall not be used as a requirement that all cord-and plug-connected equipment be of the grounded type. Informational Note: See 250.114 for types of cord- and plug-connected equipment to be grounded.

406.4(F)Receptacles connected to circuits that have different voltages, frequencies, or types of current (ac or dc) on the same premises shall be of such design that the attachment plugs used on these circuits are not interchangeable.

406.4(G)Protection for floor receptacles shall be in accordance with the following: Physical protection of floor receptacles shall allow floor-cleaning equipment to be operated without damage to receptacles.All 125-volt, single-phase, 15- and 20-ampere floor receptacles installed in food courts and waiting spaces of passenger transportation facilities where food or drinks are allowed shall be GFCI protected.

2023: on-disk 2023 rows 406.4(A)-(G) - quoted verbatim (disclosed dataset artifacts in Sources)

406.4 — 2017 (the 406.4(D)(1)–(D)(6) replacement set)
406.4 General Installation Requirements. Receptacle outlets shall be located in branch circuits in accordance with Part III of Article 210. General installation requirements shall be in accordance with 406.4(A) through (F). (A) Grounding Type. Except as provided in 406.4(D), receptacles installed on 15- and 20-ampere branch circuits shall be of the grounding type. Grounding-type receptacles shall be installed only on circuits of the voltage class and current for which they are rated, except as provided in Table 210.21(B)(2) and Table 210.21 (B) (3). (B) To Be Grounded. Receptacles and cord connectors that have equipment grounding conductor contacts shall have those contacts connected to an equipment grounding conductor. Exception No. 1: Receptacles mounted on portable and vehicle-mounted generator sets and generators in accordance with 250.34. Exception No. 2: Replacement receptacles as permitted by 406.4(D). (C) Methods of Grounding. The equipment grounding conductor contacts of receptacles and cord connectors shall be grounded by connection to the equipment grounding conductor of the circuit supplying the receptacle or cord connector. Informational Note: For installation requirements for the reduction of electrical noise, see 250.146(D). The branch-circuit wiring method shall include or provide an equipment grounding conductor to which the equipment grounding conductor contacts of the receptacle or cord connector are connected. Informational Note No. 1: See 250.118 for acceptable grounding means. Informational Note No. 2: For extensions of existing branch circuits, see 250.130. (D) Replacements. Replacement of receptacles shall comply with 406.4(D)(1) through (D)(6), as applicable. Arc-fault circuit-interrupter type and ground-fault circuit-interrupter type receptacles shall be installed in a readily accessible location. Controlled FIGURE 406.3(E) Controlled Receptacle Marking Symbol. (1) Grounding-Type Receptacles. Where a grounding means exists in the receptacle enclosure or an equipment grounding conductor is installed in accordance with 250.130(C), grounding-type receptacles shall be used and shall be connected to the equipment grounding conductor in accordance with 406.4(C) or 250.130(C). (2) Non-Grounding-Type Receptacles. Where attachment to an equipment grounding conductor does not exist in the receptacle enclosure, the installation shall comply with (D) (2) (a), (D) (2) (b), or (D) (2) (c). (a) A non-grounding-type receptacle(s) shall be permitted to be replaced with another non-grounding-type receptacle(s). (b) A non-grounding-type receptacle(s) shall be permitted to be replaced with a ground-fault circuit interrupter-type of receptacle(s). These receptacles or their cover plates shall be marked “No Equipment Ground.” An equipment grounding conductor shall not be connected from the ground-fault circuit-interrupter-type receptacle to any outlet supplied from the ground-fault circuit-interrupter receptacle. (c) A non-grounding-type receptacle(s) shall be permitted to be replaced with a grounding-type receptacle(s) where supplied through a ground-fault circuit interrupter. Where grounding-type receptacles are supplied through the groundfault circuit interrupter, grounding-type receptacles or their cover plates shall be marked “GFCI Protected” and “No Equipment Ground,” visible after installation. An equipment grounding conductor shall not be connected between the groundingtype receptacles. Informational Note No. 1: Some equipment or appliance manufacturers require that the branch circuit to the equipment or appliance includes an equipment grounding conductor. Informational Note No. 2: See 250.114 for a list of a cord-andplug-connected equipment or appliances that require an equipment grounding conductor. (3) Ground-Fault Circuit Interrupters. Ground-fault circuitinterrupter protected receptacles shall be provided where replacements are made at receptacle outlets that are required to be so protected elsewhere in this Code. Exception: Where replacement of the receptacle type is impracticable, such as where the outlet box size will not permit the installation of the GFCI receptacle, the receptacle shall be permitted to be replaced with a new receptacle of the existing type, where GFCI protection is provided and the receptacle is marked “GFCI Protected” and “No Equipment Ground,” in accordance with 406.4(D)(2)(a), (b), or (c), as applicable. (4) Arc-Fault Circuit-Interrupter Protection. Where a receptacle outlet is located in any areas specified in 210.12(A) or (B), a replacement receptacle at this outlet shall be one of the following: (1) A listed outlet branch-circuit type arc-fault circuitinterrupter receptacle (2) A receptacle protected by a listed outlet branch-circuit type arc-fault circuit-interrupter type receptacle (3) A receptacle protected by a listed combination type arcfault circuit-interrupter type circuit breaker Exception No. 1: Arc-fault circuit-interrupter protection shail not be required where all of the following apply: (1) The replacement complies with 406.4(D)(2)(b). (2) It ts tmpracticable to provide an equipment grounding conductor as provided by 250.130(C). (3) A listed combination type arc-fault circuit-interrupter circuit breaker is not commercially available. (4) GFCI/AFCI dual function receptacles are not commercially available. Exception No. 2: Section 210.12(B), Exception shall not apply to replacement of receptacles. (5) Tamper-Resistant Receptacles. Listed tamper-resistant receptacles shall be provided where replacements are made at receptacle outlets that are required to be tamper-resistant elsewhere in this Code, except where a non-grounding receptacle is replaced with another non-grounding receptacle. (6) Weather-Resistant Receptacles. Weather-resistant receptacles shall be provided where replacements are made at receptacle outlets that are required to be so protected elsewhere in this Code. (E) Cord- and Plug-Connected Equipment. The installation of grounding-type receptacles shall not be used as a requirement that all cord-and plug-connected equipment be of the grounded type. Informational Note: See 250.114 for types of cord-and plugconnected equipment to be grounded. (F) Noninterchangeable Types. Receptacles connected to circuits that have different voltages, frequencies, or types of current (ac or dc) on the same premises shall be of such design that the attachment plugs used on these circuits are not interchangeable.2017: on-disk NFPA scan §406.4 - quoted verbatim (disclosed OCR artifacts in Sources)

Delta D6 - 406.4(A) 210.21(B) citation split (Mike Holt-documented) - 2017 pointed generally at "Table 210.21(B)(2) and Table 210.21(B)(3)." 2023 splits it: 210.21(B)(1) for single receptacles or Table 210.21(B)(2) and Table 210.21(B)(3) for two or more receptacles - and the 2023 row carries a disclosed double-space artifact in "210.21(B)(1) for single".

Delta D7 - 406.4(C) re-anchored to 250.146 (Mike Holt-documented: title change) - 2017 406.4(C) "Methods of Grounding" ran the EGC contact connection to the circuit EGC plus two informational notes (250.118 acceptable means; 250.130 extensions) and carried the 250.146(D) noise-reduction note. 2023 re-anchors it: receptacle EGC contacts "shall be connected to an equipment grounding conductor of the circuit supplying the receptacle in accordance with 250.146," cord connectors handled in the second sentence, and the 250.146(D) electrical-noise note dropped.

Delta D8 - 406.4(D)(3): GFCI replacements must be LISTED (Mike Holt-documented new sentence) - 2023 adds the new last sentence: "Ground-fault circuit interrupters shall be listed." And the 2017 Exception - "Where replacement of the receptacle type is impracticable, such as where the outlet box size will not permit the installation of the GFCI receptacle..." - is trimmed to just the box-size condition. (The 2017 row also printed "Ground-fault circuitinterrupter protected receptacles shall be provided" - 2023: "Ground-fault circuit-interrupter protection for receptacles shall be provided.")

Delta D9 - 406.4(D)(4) AFCI replacement rule extended to 210.12(C) - 2017: "Where a receptacle outlet is located in any areas specified in 210.12(A) or (B)..." with Exception No. 1 (the four-condition impracticability list) and Exception No. 2. 2023: the area list gains (C) - "210.12(A), (B), or (C)" - and the Exception is reworked to the single sentence: "Section 210.12(E), Exception, shall not apply to replacement of receptacles." The 2017 Exception No. 1 condition set is deleted.

Delta D10 - 406.4(D)(5) tamper-resistant replacement rule gains the aluminum exception - 2017: TR receptacles required at TR-required outlets "except where a non-grounding receptacle is replaced with another non-grounding receptacle." 2023 converts the single exception into a two-case list and adds: "Where aluminum branch-circuit conductors are directly terminated on a CO/ALR receptacle, installed as replacement."

Delta D11 - NEW 406.4(D)(7): automatically controlled receptacle replacements - "Automatically controlled receptacles shall be replaced with equivalently controlled receptacles. If automatic control is no longer required, the receptacle and any associated receptacles marked in accordance with 406.3(F) shall be replaced with a receptacle and faceplate not marked in accordance with 406.3(F)." Zero 2017 counterpart (the 2017 (D) list ended at (D)(6)).

Delta D12 - NEW 406.4(D)(8): GFPE replacement rule - "Receptacles shall be provided with GFPE where replacements are made at receptacle outlets that are required to be so protected elsewhere in this Code." - the ground-fault protective equipment analog of the (D)(3) GFCI rule. Zero 2017 counterpart.

Delta D13 - NEW 406.4(G): protection for floor receptacles (the food-court GFCI rule) - Brand-new in 2023 (the 2017 floor-receptacle rule was 406.9(D) "Protection for Floor Receptacles" - the standpipe sentence - now relocated and rewritten here): (1) physical protection shall allow floor-cleaning equipment to operate without damage; (2) all 125 V single-phase 15/20 A floor receptacles in food courts and waiting spaces of passenger transportation facilities where food or drinks are allowed shall be GFCI protected. The old 406.9(D) standpipe sentence has zero hits in 2023.

Unchanged 2017→2023 (machine-verified word-identity): 406.4(A) lead + grounding-type rule, 406.4(B) (the (A) grounding-type lead text), 406.4(D) lead ((D)(1)–(D)(8) range aside), 406.4(D)(1), 406.4(D)(2) rules (a)-(c) + both informational notes, 406.4(D)(6), 406.4(E) (grounding-type installation is not a requirement that all equipment be grounded), 406.4(F) (noninterchangeable types).

406.5 — Mounting · 406.6 — Faceplates (the 1 W faceplate limit)

406.5 — all on-disk 2023 rows
406.5Receptacles shall be mounted in identified boxes or assemblies. The boxes or assemblies shall be securely fastened in place unless otherwise permitted elsewhere in this Code. Screws used for the purpose of attaching receptacles to a box shall be of the type provided with a listed receptacle, or shall be machine screws having 32 threads per inch or part of listed assemblies or systems, in accordance with the manufacturer's instructions.

406.5(A)Receptacles mounted in boxes that are set back from the finished surface as permitted in 314.20 shall be installed such that the mounting yoke or strap of the receptacle is held rigidly at the finished surface.

406.5(B)Receptacles mounted in boxes that are flush with the finished surface or project therefrom shall be installed such that the mounting yoke or strap of the receptacle is held rigidly against the box or box cover.

406.5(C)Receptacles mounted to and supported by a cover shall be held rigidly against the cover by more than one screw or shall be a device assembly or box cover listed and identified for securing by a single screw.

406.5(D)After installation, receptacle faces shall be flush with or project from faceplates of insulating material and shall project a minimum of 0.4 mm (0.015 in.) from metal faceplates. Exception: Listed kits or assemblies encompassing receptacles and nonmetallic faceplates that cover the receptacle face, where the plate cannot be installed on any other receptacle, shall be permitted.

406.5(E)Receptacle assemblies for installation in countertop surfaces shall be listed for countertop applications. Where receptacle assemblies for countertop applications are required to provide ground-fault circuit-interrupter protection for personnel in accordance with 210.8, such assemblies shall be permitted to be listed as GFCI receptacle assemblies for countertop applications.

406.5(F)Receptacle assemblies and GFCI receptacle assemblies listed for work surface or countertop applications shall be permitted to be installed in work surfaces.

406.5(G)(1)Receptacles shall not be installed in a face-up position in or on countertop surfaces or work surfaces unless listed for countertop or work surface applications.

406.5(G)(2)Receptacles shall not be installed in a face-up position in the area below a sink.

406.5(H)In seating areas or similar surfaces, receptacles shall not be installed in a face-up position unless the receptacle is any of the following: Part of an assembly listed as a furniture power distribution unitPart of an assembly listed either as household furnishings or as commercial furnishingsListed either as a receptacle assembly for countertop applications or as a GFCI receptacle assembly for countertop applicationsInstalled in a listed floor box

406.5(I)Receptacles shall be enclosed so that live wiring terminals are not exposed to contact.

406.5(J)A receptacle shall not be grouped or ganged in enclosures with other receptacles, snap switches, or similar devices, unless they are arranged so that the voltage between adjacent devices does not exceed 300 volts, or unless they are installed in enclosures equipped with identified, securely installed barriers between adjacent devices.

2023: on-disk 2023 rows 406.5-(J) - quoted verbatim (the 406.5(J) 300 V rule is the EX3 basis)

406.5 — 2017
406.5 Receptacle Mounting. Receptacles shall be mounted in identified boxes or assemblies. The boxes or assemblies shall be securely fastened in place unless otherwise permitted elsewhere in this Code. Screws used for the purpose of attaching receptacles to a box shall be of the type provided with a listed receptacle, or shall be machine screws having 32 threads per inch or part of listed assemblies or systems, in accordance with the manufacturer’s instructions. (A) Boxes That Are Set Back. Receptacles mounted in boxes that are set back from the finished surface as permitted in 314.20 shall be installed such that the mounting yoke or strap of the receptacle is held rigidly at the finished surface. (B) Boxes That Are Flush. Receptacles mounted in boxes that are flush with the finished surface or project therefrom shall be installed such that the mounting yoke or strap of the receptacle is held rigidly against the box or box cover. (C) Receptacles Mounted on Covers. Receptacles mounted to and supported by a cover shall be held rigidly against the cover by more than one screw or shall be a device assembly or box cover listed and identified for securing by a single screw. (D) Position of Receptacle Faces. After installation, receptacle faces shall be flush with or project from faceplates of insulating material and shall project a minimum of 0.4 mm (0.015 in.) from metal faceplates. Exception: Listed kits or assemblies encompassing receptacles and nonmetallic faceplates that cover the receptacle face, where the plate cannot be installed on any other receptacle, shall be permitted. (E) Receptacles in Countertops. Receptacle assemblies for installation in countertop surfaces shall be listed for countertop applications. Where receptacle assemblies for countertop applications are required to provide ground-fault circuit70-259 406.5 ARTICLE 406 — RECEPTACLES, CORD CONNECTORS, AND ATTACHMENT PLUGS (CAPS) interrupter protection for personnel in accordance with 210.8, such assemblies shall be permitted to be listed as GFCI receptacle assemblies for countertop applications. N (F) Receptacles in Work Surfaces. Receptacle assemblies and GFCI receptacle assemblies listed for work surface or countertop applications shall be permitted to be installed in work surfaces. N (G) Receptacle Orientation. Receptacles shall not be installed in a face-up position in or on countertop surfaces or work surfaces unless listed for countertop or work surface applications. (H) Receptacles in Seating Areas and Other Similar Surfaces. In seating areas or similar surfaces, receptacles shall not be installed in a face-up position unless the receptacle is any of the following: (1) Part of an assembly listed as a furniture power distribution unit (2) Part of an assembly listed either as household furnishings or as commercial furnishings (3) Listed either as a receptacle assembly for countertop applications or as a GFCI receptacle assembly for countertop applications (4) Installed in a listed floor box (I) Exposed Terminals. Receptacles shall be enclosed so that live wiring terminals are not exposed to contact. (J) Voltage Between Adjacent Devices. A receptacle shall not be grouped or ganged in enclosures with other receptacles, snap switches, or similar devices, unless they are arranged so that the voltage between adjacent devices does not exceed 300 volts, or unless they are installed in enclosures equipped with identified, securely installed barriers between adjacent devices. .2017: on-disk NFPA scan §406.5 - quoted verbatim (disclosed OCR artifacts in Sources)

Delta D14 - 406.5 face-up rules restructured: (G) → (G)(1) + NEW (G)(2) below-sink ban - 2017 406.5(G) was the single face-up prohibition ("Receptacles shall not be installed in a face-up position in or on countertop surfaces or work surfaces unless listed..."). 2023 splits it: (G)(1) keeps the countertop/work-surface rule and (G)(2) is new - "Receptacles shall not be installed in a face-up position in the area below a sink." (The 2017 scan also carries page furniture mid-406.5(E) - disclosed in Sources.)

406.6 — all on-disk 2023 rows
406.6Receptacle face-plates shall be installed so as to completely cover the opening and seat against the mounting surface. Receptacle faceplates mounted inside a box having a recess-mounted receptacle shall effectively close the opening and seat against the mounting surface.

406.6(A)Metal faceplates shall be of ferrous metal not less than 0.76 mm (0.030 in.) in thickness or of nonferrous metal not less than 1.02 mm (0.040 in.) in thickness.

406.6(B)Metal faceplates shall be grounded.

406.6(C)Faceplates of insulating material shall be noncombustible and not less than 2.54 mm (0.10 in.) in thickness but shall be permitted to be less than 2.54 mm (0.10 in.) in thickness if formed or reinforced to provide adequate mechanical strength.

406.6(D)A flush device cover plate that additionally provides a night light and/or Class 2 output connector(s) shall be listed and constructed such that the night light and/or Class 2 circuitry is integral with the flush device cover plate. Listed receptacle faceplates with integral night light, USB charger, or both, that rely solely on spring-tensioned contacts shall be connected to only brass or copper alloy receptacle terminal screws and shall be rated 1 watt or less. Exception: Effective January 1, 2026, spring-tensioned contact connections to steel receptacle terminal screws shall be permitted if the receptacle faceplate is specifically listed and identified for connection to steel receptacle terminal screws.

2023: on-disk 2023 rows 406.6-(D) - quoted verbatim

406.6 — 2017
406.6 Receptacle Faceplates (Cover Plates). Receptacle faceplates shall be installed so as to completely cover the opening and seat against the mounting surface. Receptacle faceplates mounted inside a box having a recessmounted receptacle shall effectively close the opening and seat against the mounting surface. (A) Thickness of Metal Faceplates. Metal faceplates shall be of ferrous metal not less than 0.76 mm (0.030 in.) in thickness or of nonferrous metal not less than 1.02 mm (0.040 in.) in thickness. (B) Grounding. Metal faceplates shall be grounded. (C) Faceplates of Insulating Material. Faceplates of insulating material shall be noncombustible and not less than 2.54 mm (0.10 in.) in thickness but shall be permitted to be less than 2.54 mm (0.10 in.) in thickness if formed or reinforced to provide adequate mechanical strength. N (D) Receptacle Faceplate (Cover Plates) with Integral Night Light and/or USB Charger. A flush device cover plate that additionally provides a night light and/or Class 2 output connector(s) shall be listed and constructed such that the night light and/or Class 2 circuitry is integral with the flush device cover plate.2017: on-disk NFPA scan §406.6 - quoted verbatim

Delta D15 - 406.6(D): the 1 W limit on spring-tensioned night-light/USB faceplates (Mike Holt-documented) - 2017 406.6(D) required listing + integral circuitry for flush cover plates with integral night light and/or Class 2 output connector(s). 2023 adds the power limit: "Listed receptacle faceplates with integral night light, USB charger, or both, that rely solely on spring-tensioned contacts shall be connected to only brass or copper alloy receptacle terminal screws and shall be rated 1 watt or less" - with a NEW Exception: effective January 1, 2026, spring-tensioned connections to steel terminal screws are permitted if the faceplate is specifically listed and identified for them. (This is the "limit the maximum power they can use" change Mike Holt called one of the coolest additions of the cycle.)

406.7 — Attachment Plugs, Cord Connectors, and Flanged Surface Devices · 406.8 — Noninterchangeability

406.7 — all on-disk 2023 rows
406.7All attachment plugs, cord connectors, and flanged surface devices (inlets and outlets) shall be listed and marked with the manufacturer's name or identification and voltage and ampere ratings.

406.7(A)Attachment plugs and cord connectors shall be constructed so that there are no exposed current-carrying parts except the prongs, blades, or pins. The cover for wire terminations shall be a part that is essential for the operation of an attachment plug or connector (dead-front construction).

406.7(B)Attachment plugs shall be installed so that their prongs, blades, or pins are not energized unless inserted into an energized receptacle or cord connectors. No receptacle shall be installed so as to require the insertion of an energized attachment plug as its source of supply.

406.7(C)Attachment plug ejector mechanisms shall not adversely affect engagement of the blades of the attachment plug with the contacts of the receptacle.

406.7(D)A flanged surface inlet shall be installed such that the prongs, blades, or pins are not energized unless an energized cord connector is inserted into it.

2023: on-disk 2023 rows 406.7-(D) - quoted verbatim

406.8 — 2017 and 2023 (word-identical, machine-verified)
Receptacles, cord connectors, and attachment plugs shall be constructed such that receptacle or cord connectors do not accept an attachment plug with a different voltage or current rating from that for which the device is intended. However, a 20-ampere T-slot receptacle or cord connector shall be permitted to accept a 15-ampere attachment plug of the same voltage rating. Non—-groundingtype receptacles and connectors shall not accept groundingtype attachment plugs.2017: on-disk NFPA scan §406.8 · 2023: on-disk 2023 row 406.8 - alpha-identical (disclosed 2023 artifact in Sources)

Unchanged 2017→2023 (machine-verified word-identity): 406.7 lead + (A)–(D) (dead-front construction, no energized blades, ejector mechanisms, flanged surface inlet) and 406.8 (the T-slot 15 A allowance + the non-grounding/grounding nonacceptance rule).

406.9 — Receptacles in Damp or Wet Locations (the 2023 rework)

406.9 — all on-disk 2023 rows
406.9(A)A receptacle installed outdoors in a location protected from the weather or in other damp locations shall have an enclosure for the receptacle that is weatherproof when the receptacle is covered (attachment plug cap not inserted and receptacle covers closed). An installation suitable for wet locations shall also be considered suitable for damp locations. A receptacle shall be considered to be in a location protected from the weather where located under roofed open porches, canopies, marquees, and the like, and will not be subjected to a beating rain or water runoff. All 125- and 250-volt nonlocking receptacles shall be a listed weather-resistant type. Hinged covers of outlet box hoods shall be able to open at least 90 degrees, or fully open if the cover is not designed to open 90 degrees from the closed to open position, after installation. Informational Note: See ANSI/NEMA WD 6-2016, Wiring Devices - Dimensional Specifications, for the types of receptacles covered by this requirement.

406.9(B)(1)Receptacles of 15 amperes and 20 amperes, 125 volts and 250 volts installed in a wet location shall have an enclosure that is weatherproof whether or not the attachment plug cap is inserted. An outlet box hood installed for this purpose shall be listed and shall be identified as extra-duty. Other listed products, enclosures, or assemblies providing weatherproof protection that do not utilize an outlet box hood need not be identified extra duty. Hinged covers of outlet box hoods shall be able to open at least 90 degrees, or fully open if the cover is not designed to open 90 degrees from the closed to open position, after installation. Informational Note No. 1: See ANSI/UL 514D-2016, Cover Plates for Flush-Mounted Wiring Devices, for extra-duty outlet box hoods. Extra duty identification and requirements are not applicable to listed receptacles, faceplates, outlet boxes, enclosures, or assemblies that are identified as either being suitable for wet locations or rated as one of the outdoor enclosure-type numbers of Table 110.28 that does not utilize an outlet box hood. Exception: 15- and 20-ampere, 125-through 250-volt receptacles installed in a wet location and subject to routine high-pressure spray washing shall be, permitted to have an enclosure that is weatherproof when the attachment plug is removed. All 15- and 20-ampere, 125- and 250-volt nonlocking-type receptacles shall be listed and so identified as the weather-resistant type. Informational Note No. 2: See ANSI/NEMA WD 6-2016, Wiring Devices - Dimensional Specifications, for receptacle configurations. The configuration of weather-resistant receptacles covered by this requirement are identified as 5-15, 5-20, 6-15, and 6-20.

406.9(B)(2)All other receptacles installed in a wet location shall be listed weather-resistant type, and installation shall comply with 406.9(B)(2)(a) or (B)(2)(b). A receptacle installed in a wet location where the product intended to be plugged into it is not attended while in use shall have an enclosure that is weatherproof with the attachment plug cap inserted or removed.A receptacle installed in a wet location where the product intended to be plugged into it will be attended while in use (e.g., portable tools) shall have an enclosure that is weatherproof when the attachment plug is removed.

406.9(C)Receptacles shall not be installed inside of the tub or shower or within a zone measured 900 mm (3 ft) horizontally from any outside edge of the bathtub or shower stall, including the space outside the bathtub or shower stall space below the zone. The zone also includes the space measured vertically from the floor to 2.5 m (8 ft) above the top of the bathtub rim or shower stall threshold. The identified zone is all-encompassing and shall include the space directly over the bathtub or shower stall and the space below this zone, but not the space separated by a floor, wall, ceiling, room door, window, or fixed barrier. Exception No. 1: Receptacles installed in accordance with 680.73 shall be permitted. Exception No. 2: In bathrooms with less than the required zone, the receptacle(s) required by 210.52(D) shall be permitted to be installed opposite the bathtub rim or shower stall threshold on the farthest wall within the room. Exception No. 3: Weight supporting ceiling receptacles (WSCR) shall be permitted to be installed for listed luminaires that employ a weight supporting attachment fitting (WSAF) in damp locations complying with 410.10(D). Exception No. 4: In a dwelling unit, a single receptacle shall be permitted for an electronic toilet or personal hygiene device such as an electronic bidet seat. The receptacle shall be readily accessible and not located in the space between the toilet and the bathtub or shower. Informational Note No. 1: See 210.8(A)(1) for GFCI requirements in a bathroom. Informational Note No. 2: See 210.11(C) for bathroom branch circuits. Informational Note No. 3: See 210.21(B)(1) for single receptacle on an individual branch.

406.9(D)The enclosure for a receptacle installed in an outlet box flush-mounted in a finished surface shall be made weatherproof by means of a weatherproof faceplate assembly that provides a watertight connection between the plate and the finished surface.

2023: on-disk 2023 rows 406.9(A)-(D) - quoted verbatim (disclosed dataset artifacts in Sources)

406.9 — 2017 (the 406.9(C) zone before the rework + the deleted 406.9(D) standpipe rule)
406.9 Receptacles in Damp or Wet Locations. (A) Damp Locations. A receptacle installed outdoors in a location protected from the weather or in other damp locations shall have an enclosure for the receptacle that is weatherproof when the receptacle is covered (attachment plug cap not inserted and receptacle covers closed). An installation suitable for wet locations shall also be considered suitable for damp locations. A receptacle shall be considered to be in a location protected from the weather where located under roofed open porches, canopies, marquees, and the like, and will not be subjected to a beating rain or water runoff. All 15- and 20-ampere, 125- and 250-volt nonlocking receptacles shall be a listed weather-resistant type. Informational Note: The types of receptacles covered by this requirement are identified as 5-15, 5-20, 6-15, and 6-20 in ANSI/ NEMA WD 6-2012, Wiring Devices — Dimensional Specifications. (B) Wet Locations. (1) Receptacles of 15 and 20 Amperes in a Wet Location. Receptacles of 15 and 20 amperes, 125 and 250 volts installed in a wet location shall have an enclosure that is weatherproof whether or not the attachment plug cap is inserted. An outlet box hood installed for this purpose shall be listed and shall be identified as “extra-duty.” Other listed products, enclosures, or assemblies providing weatherproof protection that do not utilize an outlet box hood need not be marked “extra duty.” Informational Note No. 1: Requirements for extra-duty outlet box hoods are found in ANSI/UL 514D-2013, Cover Plates for Flush-Mounted Wiring Devices. “Extra duty” identification and requirements are not applicable to listed receptacles, faceplates, outlet boxes, enclosures, or assemblies that are identified as either being suitable for wet locations or rated as one of the outdoor enclosure-type numbers of Table 110.28 that does not utilize an outlet box hood. Exception: 15- and 20-ampere, 125- through 250-volt receptacles installed in a wet location and subject to routine high-pressure spray washing shall be permitted to have an enclosure that is weatherproof when the attachment plug is removed. All 15- and 20-ampere, 125- and 250-volt nonlocking-type receptacles shall be listed and so identified as the weatherresistant type. Informational Note No. 2: The configuration of weatherresistant receptacles covered by this requirement are identified as 5-15, 5-20, 6-15, and 6-20 in ANSI/NEMA WD 6-2012, Wiring Devices — Dimensional Specifications. (2) Other Receptacles. All other receptacles installed in a wet location shall comply with (B) (2) (a) or (B) (2) (b). (a) A receptacle installed in a wet location, where the product intended to be plugged into it is not attended while in use, shall have an enclosure that is weatherproof with the attachment plug cap inserted or removed. (b) A receptacle installed in a wet location where the product intended to be plugged into it will be attended while in use (e.g., portable tools) shall have an enclosure that is weatherproof when the attachment plug is removed. (C) Bathtub and Shower Space. Receptacles shall not be installed within or directly over a bathtub or shower stall. (D) Protection for Floor Receptacles. Standpipes of floor receptacles shall allow floor-cleaning equipment to be operated without damage to receptacles. (E) Flush Mounting with Faceplate. The enclosure for a receptacle installed in an outlet box flush-mounted in a finished surface shall be made weatherproof by means of a weatherproof faceplate assembly that provides a watertight connection between the plate and the finished surface.2017: on-disk NFPA scan §406.9 - quoted verbatim (disclosed OCR artifacts in Sources)

Delta D16 - 406.9(A) damp locations: NEW 90-degree hinged-cover rule (Mike Holt-documented) - 2023 adds to the damp-location rule: "Hinged covers of outlet box hoods shall be able to open at least 90 degrees, or fully open if the cover is not designed to open 90 degrees from the closed to open position, after installation." The weather-resistant identification note also moves its standard cite from ANSI/NEMA WD 6-2012 to ANSI/NEMA WD 6-2016.

Delta D17 - 406.9(B)(1) wet locations: standard re-cites + the "extra duty" wording - The wet-location 15/20 A rule re-cites ANSI/UL 514D-2016 (2017: ANSI/UL 514D-2013), rewords the non-hood carve-out from "marked extra duty" to "identified extra duty," and carries a disclosed 2023 dataset artifact in its Exception (lowercase "shall be, permitted"). The 90-degree hinged-cover sentence that 2023 added to the damp rule (D16) has no 2017 counterpart on either side.

Delta D18 - 406.9(C): from "within or directly over" to the 900 mm × 2.5 m zone + four exceptions (Mike Holt-documented) - 2017 406.9(C) was one sentence: "Receptacles shall not be installed within or directly over a bathtub or shower stall." 2023 rewrites it as a measured zone: 900 mm (3 ft) horizontally from any outside edge of the bathtub or shower stall (including the space outside and below the zone), measured vertically from the floor to 2.5 m (8 ft) above the top of the rim/threshold - "all-encompassing," but not crossing a floor, wall, ceiling, room door, window, or fixed barrier - plus four new exceptions: (1) 680.73 pool installations, (2) 210.52(D) bathroom receptacles on the farthest wall where the zone is less than required, (3) weight-supporting ceiling receptacles (WSCR) for WSAF luminaires per 410.10(D), and (4) a single receptacle for an electronic toilet or personal hygiene device (e.g., electronic bidet seat) in a dwelling unit - readily accessible, not between the toilet and the tub/shower. (This is the "bathroom receptacle rules have become more complicated" change Mike Holt flagged; the same 900 mm × 2.5 m geometry appears in the 2023 422.18(B) fan rule.)

Unchanged 2017→2023 (machine-verified word-identity): 406.9(A) lead (weatherproof-when-covered damp rule), 406.9(B)(2) both routes (attended / not-attended), and 406.9(D) (the flush-mounted finished-surface weatherproof faceplate assembly).

406.10 — Grounding-Type Receptacles · 406.11 — Connecting the Grounding Terminal to the Box

406.10 — all on-disk 2023 rows
406.10(A)Grounding-type receptacles, cord connectors, and attachment plugs shall be provided with one fixed grounding pole in addition to the circuit poles. The grounding contacting pole of grounding-type plug-in ground-fault circuit interrupters shall be permitted to be of the movable, self-restoring type on circuits operating at not over 150 volts between any two conductors or any conductor and ground.

406.10(B)Grounding-type receptacles, adapters, cord connections, and attachment plugs shall have a means for connection of an equipment grounding conductor to the grounding pole. A terminal for connection to the grounding pole shall be designated by one of the following:A green-colored hexagonal-headed or -shaped terminal screw or nut, not readily removable.A green-colored pressure wire connector body (a wire barrel).A similar green-colored connection device, in the case of adapters. The grounding terminal of a grounding adapter shall be a green-colored rigid ear, lug, or similar device. The equipment grounding connection shall be so designed that it cannot make contact with current-carrying parts of the receptacle, adapter, or attachment plug. The adapter shall be polarized.If the terminal for the equipment grounding conductor is not visible, the conductor entrance hole shall be marked with the word green or ground, the letters G or GR, a grounding symbol, or otherwise identified by a distinctive green color. If the terminal for the equipment grounding conductor is readily removable, the area adjacent to the terminal shall be similarly marked. Informational Note: See Informational Note Figure 406.10(B). Informational Note Figure 406.10(B) One Example of a Symbol Used to Identify the Termination Point for an Equipment Grounding Conductor.

406.10(C)A grounding terminal shall not be used for purposes other than connection to the equipment grounding conductor.

406.10(D)Grounding-type attachment plugs and mating cord connectors and receptacles shall be designed such that the equipment grounding connection is made before the current-carrying connections. Grounding-type devices shall be so designed that grounding poles of attachment plugs cannot be brought into contact with current-carrying parts of receptacles or cord connectors.

406.10(E)Grounding-type attachment plugs shall be used only with a cord having an equipment grounding conductor. Informational Note: See 250.126 for identification of equipment grounding conductor terminals.

2023: on-disk 2023 rows 406.10(A)-(E) - quoted verbatim (the (B) list-item artifact disclosed in Sources)

406.10 — 2017
406.10 Grounding-Type Receptacles, Adapters, Cord Connectors, and Attachment Plugs. (A) Grounding Poles. Grounding-type receptacles, cord connectors, and attachment plugs shall be provided with one fixed grounding pole in addition to the circuit poles. The grounding contacting pole of grounding-type plug-in groundfault circuit interrupters shall be permitted to be of the movable, self-restoring type on circuits operating at not over 150 volts between any two conductors or any conductor and ground. (B) Grounding-Pole Identification. Grounding-type receptacles, adapters, cord connections, and attachment plugs shall have a means for connection of an equipment grounding conductor to the grounding pole. A terminal for connection to the grounding pole shall be designated by one of the following: (1) A green-colored hexagonal-headed or -shaped terminal screw or nut, not readily removable. (2) A green-colored pressure wire connector body (a wire barrel). (3) A similar green-colored connection device, in the case of adapters. The grounding terminal of a grounding adapter shall be a green-colored rigid ear, lug, or similar device. The equipment grounding connection shall be so designed that it cannot make contact with current carrying parts of the receptacle, adapter, or attachment plug. The adapter shall be polarized. (4) If the terminal for the equipment grounding conductor is not visible, the conductor entrance hole shall be marked with the word green or ground, the letters G or GR, a grounding symbol, or otherwise identified by a distinctive green color. If the terminal for the equipment grounding conductor is readily removable, the area adjacent to the terminal shall be similarly marked. Informational Note: See Informational Note 406.10(B) (4). Figure (C) Grounding Terminal Use. A grounding terminal shall not be used for purposes other than grounding. (D) Grounding-Pole Requirements. Grounding-type attachment plugs and mating cord connectors and receptacles shall be designed such that the equipment grounding connection is made before the current-carrying connections. Grounding-type devices shall be so designed that grounding poles of attachment plugs cannot be brought into contact with currentcarrying parts of receptacles or cord connectors. (E) Use. Grounding-type attachment plugs shall be used only with a cord having an equipment grounding conductor. Informational Note: See 250.126 for identification of grounding conductor terminals.2017: on-disk NFPA scan §406.10 - quoted verbatim (disclosed scan artifacts in Sources: 'groundfault' without the internal hyphen in (A), 'currentcarrying' in (D), and the 'Figure 4' misprint for 'Informational Note 4' in (B)(4))

406.11 — 2017 and 2023 (word-identical, machine-verified)
The connection of the receptacle grounding terminal shall comply with 250.146.2017: on-disk NFPA scan §406.11 · 2023: on-disk 2023 row 406.11 - alpha-identical

Delta D19 - 406.10(C) grounding-terminal use: "for purposes other than grounding" → "other than connection to the equipment grounding conductor" - 2017 406.10(C): "A grounding terminal shall not be used for purposes other than grounding." 2023: "A grounding terminal shall not be used for purposes other than connection to the equipment grounding conductor" - the prohibition is now tied to the specific conductor, not the abstract concept. The 406.10(E) informational note also changes: 2017 "See 250.126 for identification of grounding conductor terminals" → 2023 "See 250.126 for identification of equipment grounding conductor terminals." (2017 406.10(B)(4) also carried the "See Informational Note 406.10(B)(4). Figure" note - 2023 prints "See Informational Note Figure 406.10(B)." - a disclosed dataset artifact; the 2017 scan misprints the note label "Informational Note 4" as "Figure 4.")

406.12 — Tamper-Resistant Receptacles (7 → 10 required locations)

406.12 — 2023 (the full reworked section)
All 15- and 20-ampere, 125- and 250-volt nonlocking-type receptacles in the following locations shall be listed tamper-resistant receptacles: All dwelling units, boathouses, mobile homes and manufactured homes, including their attached and detached garages, accessory buildings, and common areasGuest rooms and guest suites of hotels, motels, and their common areasChild care facilitiesPreschools and education facilitiesWithin clinics, medical and dental offices, and outpatient facilities, the following spaces:Business offices accessible to the general publicLobbies, and waiting spacesSpaces of nursing homes and limited care facilities covered in 517.10(B)(2)Places of awaiting transportation, gymnasiums, skating rinks, fitness centers, and auditoriumsDormitory unitsResidential care/assisted living facilities, social and substance abuse rehabilitation facilities, and group homesFoster care facilities, nursing homes, and psychiatric hospitalsAreas of agricultural buildings accessible to the general public and any common areasInformational Note No. 1: See ANSI/NEMA WD 6-2016, Wiring Devices - Dimensional Specifications. This requirement would include receptacles identified as 5-15, 5-20, 6-15, and 6-20.Informational Note No. 2: See NFPA 5000-2021, Building Construction and Safety Code, and the International Building Code (IBC)-2021 for more information on occupancy classifications for the types of facilities covered by this requirement.Informational Note No. 3: Areas of agricultural building are frequently converted to hospitality areas. These areas can include petting zoos, stables, and buildings used for recreation or educational purposes where receptacles are installed.Exception to (1) through (10): Receptacles in the following locations shall not be required to be tamper resistant:Receptacles located more than 1.7 m (51/2 ft) above the floorReceptacles that are part of a luminaire or applianceWhere the receptacle outlet is installed within the space occupied by or designated for each appliance that, in normal use, is not easily moved from one place to another and is cord-and-plug-connected in accordance with 400.10(A)(6), (A)(7), or (A)(8) the following are permitted:A single receptacle that is not readily accessible and supplies one applianceA duplex receptacle that is not readily accessible and supplies two appliancesNongrounding receptacles used for replacements as permitted in 406.4(D)(2)(a)2023: on-disk 2023 row 406.12 - quoted verbatim (the list-item concatenation artifact disclosed in Sources)

406.12 — 2017 (the seven-location rule)
406.12 Tamper-Resistant Receptacles. All 15- and 20-ampere, 125- and 250-volt nonlocking-type receptacles in the areas specified in 406.12(1) through (7) shall be listed tamper resistant receptacles. (1) Dwelling units in all areas specified in 210.52 and 550.13 (2) Guest rooms and guest suites of hotels and motels (3) Child care facilities (4) Preschools and elementary education facilities (5) Business offices, corridors, waiting rooms and the like in clinics, medical and dental offices and outpatient facilities (6) Subset of assembly occupancies described in 518.2 to include places of waiting transportation, gymnasiums, skating rinks, and auditoriums (7) Dormitories Informational Note: This requirement would include receptacles identified as 5-15, 5-20, 6-15, and 6-20 in ANSI/NEMA WD 6-2016, Wiring Devices — Dimensional Specifications. Exception to (1), (2), (3), (4), (5), (6), and (7): Receptacles in the Jollowing locations shall not be required to be tamper resistant: (1) Receptacles located more than 1.7 m (5 '4 ft) above the floor Informational Note Figure 406.10(B)(4) | One Example of a Symbol Used to Identify the Termination Point for an Equipment Grounding Conductor. 408.1 ARTICLE 408 — SWITCHBOARDS, SWITCHGEAR, AND PANELBOARDS (2) Receptacles that are part of a luminaire or appliance (3) A single receptacle or a duplex receptacle for two appliances located within the dedicated space for each appliance that, in normal use, is not easily moved from one place to another and that ts cord-and-plug-connected in accordance with 400.10(A)(6), (A)(7), or (A)(8) (4) Nongrounding receptacles used for replacements as permitted in 406.4(D)(2)(a)2017: on-disk NFPA scan §406.12 - quoted verbatim (disclosed OCR artifacts in Sources, incl. the Figure 406.10(B)(4) caption bleed)

Delta D20 - 406.12: 7 required locations (2017) → 10 (2023) (Mike Holt-documented) - 2017 required TR receptacles at (1) dwelling-unit 210.52/550.13 areas, (2) hotel/motel guest rooms and suites, (3) child care facilities, (4) preschools and elementary education facilities, (5) clinics/medical/dental/outpatient business offices, corridors, waiting rooms, (6) a subset of assembly occupancies (518.2), (7) dormitories. 2023 keeps those (expanded: "All dwelling units, boathouses, mobile homes and manufactured homes, including their attached and detached garages, accessory buildings, and common areas"; hotels "and their common areas"; preschools "and education facilities") and adds (8) residential care/assisted living facilities, social and substance abuse rehabilitation facilities, and group homes; (9) foster care facilities, nursing homes, and psychiatric hospitals; (10) areas of agricultural buildings accessible to the general public and any common areas. New informational notes: NFPA 5000-2021 + IBC-2021 occupancy classification (No. 2) and the agricultural-building conversion note (No. 3). The Exception set is reworked too - the appliance-space exception now allows a single non-readily-accessible receptacle for one appliance OR a duplex for two (the 2017 phrasing was one receptacle or a duplex "located within the dedicated space"). Zero 2017 hits: "boathouses," "assisted living," "psychiatric hospitals," "agricultural buildings."

406.13 — Single-Pole Separable Connectors (NEW in 2023)

406.13 — all on-disk 2023 rows (406.13(A)–(D))
406.13Single-pole separable connectors shall be listed and labeled and shall comply with 406.13(A) through (D).

406.13(A)Single-pole separable connectors shall be of either the locking or latching type and marked with the manufacturer's name or identification and voltage and ampere ratings.

406.13(B)Connectors designated for connection to the grounded circuit conductor shall be identified by a white-colored housing; connectors designated for connection to the grounding circuit conductor shall be identified by a green-colored housing.

406.13(C)Single-pole separable connectors shall be permitted to be interchangeable for ac or dc use or for different current ratings or voltages on the same premises, provided they are listed for ac/dc use and marked in a suitable manner to identify the system to which they are intended to be connected.

406.13(D)The use of single-pole separable connectors shall be performed by a qualified person and shall comply with at least one of the following conditions: Connection and disconnection of connectors are only possible where the supply connectors are interlocked to the source, and it is not possible to connect or disconnect connectors when the supply is energized.Line connectors are of the listed sequential-interlocking type so that load connectors are connected in the following sequence and that disconnection is in the reverse sequence:Equipment grounding conductor connectionGrounded circuit conductor connection, if providedUngrounded conductor connectionA caution notice that complies with 110.21 (B) is provided on the equipment employing single-pole separable connectors, adjacent to the line connectors, indicating that connections are to be performed in the following sequence and that disconnection is in the reverse sequence:Equipment grounding conductor connectorsGrounded circuit-conductor connectors, if providedUngrounded conductor connectorsInformational Note: See ANSI-UL 1691-2014, Single Pole Locking-Type Separable Connectors, for more information on single-pole locking-type separable connectors.

2023: on-disk 2023 rows 406.13-(D) - quoted verbatim (the (B) "grounding circuit conductor" artifact disclosed in Sources)

Delta D21 - NEW 406.13: the entire section is new (no Mike Holt entry - the 2017 scan has zero 406.13) - The 2017 Article 406 region ends at 406.12 - the on-disk scan has zero 406.13 tokens. 2023 adds the full single-pole separable-connector section: (A) locking or latching type, marked with manufacturer + voltage/ampere ratings; (B) white housing for the grounded circuit conductor, green for the grounding conductor connection (the 2023 row prints "grounding circuit conductor" where the 2017-era convention says "grounded circuit conductor" - a disclosed dataset artifact); (C) ac/dc interchangeability only if listed and marked; (D) qualified-persons use with interlock - either the supply connectors are interlocked to the source (no connect/disconnect when energized) or listed sequential-interlocking type with the EGC-first connection sequence and the 110.21(B) caution notice, per the ANSI-UL 1691-2014 informational note. This is the article that governs the "quick-disconnect" plugs on modern kitchen islands and commercial equipment.

The 21 machine-diffed 2017→2023 deltas, at a glance

#	Section	What moved 2017 → 2023
D1	406.2	Subject swap: definitions (Child Care Facility, Outlet Box Hood) deleted → reconditioned-equipment ban
D2	406.3(C)	Title clarified: covers receptacles marked CO/ALR (MH-documented)
D3	406.3(D)	NEW: terminations - CO/ALR copper-clad rule + push-in 15 A / 14 AWG solid copper corner
D4	406.3(E)→(F)	Controlled marking renumbered (Figure 406.3(F)); (E) taken by isolated ground
D5	406.3(E)(2)	Faceplate exception: "effective grounding" → "connection to the equipment grounding conductor"
D6	406.4(A)	210.21(B) cite split: (B)(1) single receptacles / (B)(2)+(B)(3) two or more (MH-documented)
D7	406.4(C)	Re-anchored to 250.146; noise-reduction note dropped (MH-documented title change)
D8	406.4(D)(3)	"GFCI shall be listed" added; impracticability Exception trimmed to box-size (MH-documented)
D9	406.4(D)(4)	AFCI replacement rule extended to 210.12(C); Exception No. 1 condition set deleted → 210.12(E) Exception sentence
D10	406.4(D)(5)	TR replacement rule: NEW aluminum/CO/ALR exception case
D11	406.4(D)(7)	NEW: automatically controlled receptacles replaced with equivalently controlled (or unmarked) ones
D12	406.4(D)(8)	NEW: GFPE required at GFPE-required outlets when replaced
D13	406.4(G)	NEW: floor receptacles - cleaning-equipment protection + GFCI in food courts / passenger-transportation waiting spaces (2017 406.9(D) standpipe sentence deleted)
D14	406.5(G)	Face-up rules split: (G)(1) countertops/work surfaces + NEW (G)(2) below-sink ban
D15	406.6(D)	1 W limit on spring-tensioned night-light/USB faceplates (brass/copper terminals only) + Jan 1, 2026 steel-screw Exception (MH-documented)
D16	406.9(A)	NEW: 90-degree (or fully-open) hinged outlet box covers in damp locations; WD 6-2012 → WD 6-2016 (MH-documented)
D17	406.9(B)(1)	ANSI/UL 514D-2013 → 514D-2016; "marked" → "identified" extra duty
D18	406.9(C)	One-sentence tub/shower ban → 900 mm × 2.5 m measured zone + 4 new exceptions (bidet, 680.73, WSCR, 210.52(D) farthest wall) (MH-documented)
D19	406.10(C)	"other than grounding" → "other than connection to the equipment grounding conductor"
D20	406.12	7 → 10 required TR locations (+boathouses/mobile homes, care facilities, foster care/psychiatric, agricultural); NFPA 5000-2021 + IBC-2021 notes (MH-documented)
D21	406.13	NEW section: single-pole separable connectors (interlock + sequential EGC-first connection, ANSI-UL 1691)

Machine-counted silence: the on-disk Mike Holt 2023 change summary carries five in-scope Article 406 entries (406.3, 406.4, 406.6, 406.9, 406.12), quoted verbatim below. The other sixteen deltas are direct on-disk 2017-scan ↔ 2023-dataset diffs, not summary-sourced claims. 2020 edition gap (honest scope): the on-disk 2020 source (slideshare scan) carries no Article 406 body text - its only 406.x tokens are two cross-reference pairs ("406.S(E) and 406.S(G)" and "406.5(E) and 406.5(G)" - the first with the scan's "S" for "5" OCR misread) with no section body (machine-asserted), so no 2020 position is asserted anywhere on this page; the edition story is 2017 ↔ 2023, both sides on disk.

The five on-disk Mike Holt 2023 change-summary entries (quoted verbatim)

"406.3 Receptacle Rating and Type— The title of (C) was changed to clarify that this section covers receptacles marked CO/ALR and a new subdivision (D) is another change related to the use of copper-clad aluminum conductors."
On-disk Mike Holt 2023 change summary - quoted verbatim.

"406.4 General Installation Requirements— The titles of both (B) and (C) were changed to be specific as to the type of grounding conductor covered in the subdivision. In addition, a new last sentence was added to (D)(3) requiring a GFCI to be a listed device."
On-disk Mike Holt 2023 change summary - quoted verbatim.

"406.6 Receptacle Faceplates—One of the coolest recent additions to the array of device faceplates is the integral night light and USB charger faceplate. Changes this cycle limit the maximum power they can use."
On-disk Mike Holt 2023 change summary - quoted verbatim.

"406.9 Receptacles in Damp or Wet Locations— Hinged covers of outlet box hoods must now open at least 90° after installation, other than 15A and 20A receptacles are required to be weather resistant, and bathroom receptacle rules have become more complicated."
On-disk Mike Holt 2023 change summary - quoted verbatim. On-disk caveat: "other than 15A and 20A receptacles" is Mike Holt's shorthand - the on-disk 2023 row (406.9(B)(1)) requires ALL 15- and 20-ampere, 125- and 250-volt nonlocking-type receptacles to be listed weather-resistant; the on-disk record controls.

"406.12 Tamper-Resistant Receptacles— These rules were expanded once again to include additional required locations."
On-disk Mike Holt 2023 change summary - quoted verbatim.

Six worked examples (every number from the real shipped PanelWright core, zero hand math)

EX1 - the 406.3(B) rating floor on a 20 A small-appliance circuit (the 240.4(D) trap)

A 20 A small-appliance branch circuit (the 210.52(B) circuit type every panel schedule carries). 406.3(B): the receptacles on it must be rated "15 A / 125 V or 15 A / 250 V" - a 20 A 125 V receptacle passes (20 ≥ 15). The branch conductors for the 20 A OCPD, machine-computed from the shipped core: the naive ampacity pick (75 °C column) is 14 AWG Cu (20 A) - but 240.4(D) caps 14 AWG Cu at 15 A < the 20 A OCPD, so 14 AWG is rejected (naive_rejected = true). The correct pick is 12 AWG Cu (25 A @ 60 °C) - its 240.4(D) cap is 20 A = the OCPD, so it passes.

core: pickConductor31016(20, "cu", 75) = 14 (rejected by 240.4(D)); pickConductor31016(20, "cu", 60) = 12; smallConductorCap(14,"cu") = 15 A; smallConductorCap(12,"cu") = 20 A

EX2 - the 406.3(D) push-in-terminal corner (NEW in 2023)

A 15 A branch circuit terminated in a screwless push-in receptacle. 406.3(D): push-in terminals "shall be installed on not greater than 15-ampere branch circuits and shall be connected with 14 AWG Cu wire only" unless listed for other conductors. Machine check: a 15 A OCPD is exactly at the branch cap (15 ≤ 15, passes); the 240.4(D) cap for 14 AWG Cu is 15 A = the OCPD (the two caps coincide - the 15 A / 14 AWG pair is the legal maximum for this termination type). The same circuit on a 20 A OCPD would violate 406.3(D) outright - the branch itself is over the 15 A cap.

branch cap: 15 A (406.3(D)); pickConductor31016(15, "cu", 75) = 14 AWG; smallConductorCap(14,"cu") = 15 A = OCPD

EX3 - the 406.5(J) 300 V adjacent-device limit

406.5(J): a receptacle "shall not be grouped or ganged in enclosures with other receptacles, snap switches, or similar devices" unless the voltage between adjacent devices does not exceed 300 volts (or identified, securely installed barriers are present). The machine arithmetic on the on-disk 300 V limit for four ganged-pair cases:

Adjacent ganged devices	Max voltage between them	406.5(J) without barriers
120 V circuit + 120 V circuit	120 V	passes (≤ 300 V)
120 V circuit + 240 V circuit	240 V	passes (≤ 300 V)
120 V circuit + 277 V circuit	277 V	passes (≤ 300 V)
120 V circuit + 480 V circuit	480 V	FAILS (bars required)

limit: 300 V (406.5(J), on-disk value); 120/240 V duplex pairs pass, 120/480 V pairs need barriers or separate enclosures

EX4 - the 406.9(C) bathtub/shower zone (2023 rework)

The 2023 zone: 900 mm (3 ft) horizontally from any outside edge of the tub or shower stall, measured vertically from the floor to 2.5 m (8 ft) above the top of the rim/threshold. Machine check on two typical installs: a receptacle 610 mm (24 in.) from the tub edge → true the 900 mm zone (prohibited without an Exception); a wall receptacle 1050 mm (42 in.) from the edge → outside the zone (permitted, GFCI still required per 210.8(A)(1) - the 406.9(C) Informational Note No. 1). The 2017 one-sentence rule ("within or directly over") had no numeric boundary at all - the 2023 rework is what makes the zone checkable.

zone: 900 mm x 2.5 m (on-disk 2023 values); 610 mm → inside (prohibited); 1050 mm → outside (permitted + GFCI per 210.8)

EX5 - the 406.13(D) sequential-interlock connection sequence (2023 NEW section)

For a listed sequential-interlocking single-pole separable connector (ANSI-UL 1691-2014), 406.13(D) fixes the connection order - and disconnection is the reverse:

Step	Conductor
1	Equipment grounding conductor connection
2	Grounded circuit conductor connection, if provided
3	Ungrounded conductor connection

source: on-disk 2023 row 406.13(D); list ref: ANSI-UL 1691-2014, Single Pole Locking-Type Separable Connectors

EX6 - the 406.12 machine count: 7 → 10 locations + the 1.7 m height seam

The 406.12 expansion, machine-counted: 7 required locations in 2017 → 10 in 2023 (+3: care facilities, foster care/nursing/psychiatric, agricultural buildings). And the height Exception boundary, both sides of the 1.7 m (5½ ft) line: a receptacle at 1.65 m (65 in.) above the floor → true (TR required); at 1.80 m (71 in.) → exempt.

count: 7 → 10; height seam: 1.7 m - 1.65 m required, 1.80 m exempt

Frequently asked questions

Q: What does Article 406 actually cover?
The devices, not the circuits: receptacles, cord connectors, and attachment plugs (cord caps) - their rating (406.3: not less than 15 A, 125 V or 15 A, 250 V; the 2023-new 406.3(D) termination rules), installation (406.4: grounding type, the (D)(1)-(D)(8) replacement rules), mounting (406.5: boxes, faceplates, the (J) 300 V adjacent-device limit), faceplates (406.6: thickness, grounding, the 406.6(D) 1 W night-light/USB limit), attachment plugs (406.7), noninterchangeability (406.8), damp/wet locations (406.9), grounding-type details (406.10-406.11), tamper-resistant receptacles (406.12), and - new in 2023 - single-pole separable connectors (406.13). Branch-circuit rules live in Article 210 (210.52 outlet counts, 210.8 GFCI, 210.12 AFCI) - this article is what makes the device at the end of each circuit legal.

Q: What changed in Article 406 from 2017 to 2023?
21 machine-diffed deltas (table above). The big ones: 406.2 became the reconditioned-equipment ban (definitions deleted); NEW 406.3(D) terminations (the 15 A / 14 AWG push-in corner + the CO/ALR copper-clad rule); the 406.3(E)→(F) controlled-marking renumber; 406.4(A) citation split; 406.4(C) re-anchored to 250.146; 406.4(D)(3) GFCI-listed sentence; 406.4(D)(4) extended to 210.12(C); the aluminum/CO/ALR replacement exception (D10); NEW (D)(7) automatically controlled replacements, (D)(8) GFPE, (G) floor receptacles (food-court GFCI); the 406.5(G)(2) below-sink face-up ban; the 406.6(D) 1 W faceplate limit (with the 2026 steel-screw Exception); 406.9(A) 90-degree hinged covers; the 406.9(C) bathtub zone (900 mm × 2.5 m + 4 exceptions); 406.10(C) reword; the 406.12 expansion (7 → 10 locations); and the brand-new 406.13 single-pole separable-connector section. No existing section number was deleted - the movement is additive, plus the 406.2 subject swap.

Q: Where are tamper-resistant receptacles required in 2023?
At every 15/20 A, 125/250 V nonlocking receptacle outlet in ten location classes: (1) all dwelling units (including boathouses, mobile/manufactured homes, garages, accessory buildings, common areas), (2) hotel/motel guest rooms and common areas, (3) child care facilities, (4) preschools and education facilities, (5) clinics/medical/dental/outpatient spaces (public offices, lobbies, waiting spaces), (6) places of awaiting transportation, gymnasiums, skating rinks, fitness centers, auditoriums, (7) dormitory units, (8) residential care/assisted living, social and substance abuse rehabilitation, group homes, (9) foster care facilities, nursing homes, psychiatric hospitals, (10) agricultural-building areas accessible to the public + common areas. Exceptions: over 1.7 m (5½ ft), luminaires/appliances, the appliance-space receptacles (single or duplex, not readily accessible), and nongrounding replacement receptacles per 406.4(D)(2)(a).

Q: What is the new 406.13, and what does it require?
Single-pole separable connectors (the "quick-disconnect" plugs) must be listed and labeled, locking or latching type, marked with the manufacturer and voltage/ampere ratings. The grounded-conductor side gets a white housing, the grounding-conductor side green. Ac/dc interchangeability requires listing + marking. And - the core of the section - use must be by a qualified person, with either source-interlocked supply connectors (no connect/disconnect while energized) or listed sequential-interlocking type connecting in the order EGC → grounded conductor → ungrounded (reverse for disconnect), with an 110.21(B) caution notice adjacent to the line connectors. The informational note points to ANSI-UL 1691-2014.

Sources & verification method

2017 text: on-disk official NFPA 70 (2017 NEC) scan, Article 406 region (lines 45487-46222 of the flat extraction), machine-reflowed into 12 top-level sections (s93_406_2017_sections.json). Disclosed OCR/scan artifacts (each machine-asserted in the verify script): "shail" for "shall" (406.4(D)(4) Exception No. 1), "It ts tmpracticable" for "It is impracticable" (406.4(D)(4) Exception No. 1), "ts" for "is" (406.5(E) fragment "that ts cord-and-plug-connected" is actually in 406.12 Exception (3); 406.5(E) carries the "70-259" page noise + the 406.5 running-header bleed), "Jollowing" for "Following" (406.12 Exception), "that ts cord-and-plug-connected" (406.12 Exception (3)), the Figure 406.10(B)(4) caption bleed printed mid-406.12, the "Figure 4" misprint for "Informational Note 4" (406.10(B)(4)), "groundfault circuit interrupter" without the internal hyphen (406.4(D)(2)(c)/(3) and 406.10(A)), the "currentcarrying" concatenation (406.10(D)), "Non——groundingtype" double em-dash (406.8), and the 406.5(E) "circuit70-259 406.5 ARTICLE 406 ..." mid-bleed (furniture trimmed by the cleaner; the 2023 text is shown for 406.5 in the delta context).
2023 text: on-disk 2023 NEC dataset (art35_nec_csv.csv), all 67 Article 406 rows - the complete article in the dataset (406.1 through 406.13(D)). Disclosed 2023 dataset artifacts: the double space in "210.21(B)(1) for single" (406.4(A)), lowercase "shall be, permitted" in the Exception (406.9(B)(1)), "grounding circuit conductor" for "grounded circuit conductor" (406.13(B)), "groundfault circuit interrupter" without the internal hyphen (406.4(D)(2)(c)), the list-item concatenation (406.12 location list + 406.10(B) terminal list print as run-together text), and the "See Informational Note Figure 406.10(B)." note (406.10(B)).
Mike Holt 2023 change summary: on-disk (art48_mh23cc_full.txt) - exactly five in-scope Article 406 entries (406.3, 406.4, 406.6, 406.9, 406.12), quoted verbatim above; the other sixteen deltas are direct on-disk diffs, not summary claims (machine-counted silence asserted). The 406.9 entry's "other than 15A and 20A" shorthand is flagged against the on-disk 2023 row, which controls.
2020 edition gap: the on-disk 2020 source (slideshare scan) carries no Article 406 body - its only 406.x tokens are two cross-reference pairs ("406.S(E) and 406.S(G)" and "406.5(E) and 406.5(G)" - the first with the scan's "S" for "5" OCR misread) with no section body (machine-asserted), so no 2020 position is asserted.
Worked examples: every number computed by the shipped PanelWright core (pickConductor31016, nextStdBreaker, smallConductorCap) under node (compute_art68.js → art68_numbers.json), plus direct arithmetic on on-disk rule values - zero hand math; the test suite re-runs the core and compares.
Verification: verify_art68.py runs the machine checks (all 67 2023 rows present, all 12 2017 sections present, the 21 deltas both-sided, the identity word-checks, the zero-hit absence claims, the five MH-entry probes, the worked figures, the core re-run, the sitemap/index/README entries, tag balance) - the count in the footer is the script's actual total, and a self-consistency check prevents the page from claiming a number the verifier does not run. 172 machine-verified checks - all 172 pass.

Scope & honesty: this is a design aid, not code commentary and not engineering advice. The adopted edition in your jurisdiction governs. Where 2017 and 2023 differ, the delta boxes say what moved; where a number is quoted from a scan, the disclosed OCR artifacts are listed. AI-built, AI-verified, fully disclosed.