Continuing our Code Journey: Accepting (NEC) change, part 10

The flexible bus requirement is in new Article 371. This photo shows a cross section of the product. Note the braided conductor, which gives the product its flexibility. | Mark Earley
The flexible bus requirement is in new Article 371. This photo shows a cross section of the product. Note the braided conductor, which gives the product its flexibility.
Mark Earley
Published On
Nov 15, 2022

Let’s finish our walk-through of the changes to Chapter 3 in the 2023 National Electrical Code. Then we can start looking at Chapter 4.

342.24 Bends. The cable and raceway articles in Chapter 3 follow a common format that calls for parallel numbering of sections. There have been two sections on bends in each of these articles. For example, in Article 342, the sections were 342.24 Bends—How Made, and 342.26 Bends—Number in One. Starting with the 2023 Code, those sections will be combined into a single Section 342.24 Bends. The previous content of 342.24 is now in (A) and the previous content of 342.25 is now in (B). The language about the number of quarter bends has been replaced with an explicit statement that prohibits the total degrees of bends from exceeding 360 degrees between pull points.

The language had been previously misinterpreted by some to prohibit bends that exceeded 90 degrees. Some only counted quarter bends and did not consider bends that were less than 90 degrees.

The combined section XXX.24 will appear as follows:

  • 344.24 Rigid Metal Conduit

  • 352.24 Rigid Polyvinyl Chloride Conduit

  • 353.24 High-Density Polyethylene Conduit

  • 354.24 Nonmetallic Underground Conduit with Conductors

  • 355.24 Reinforced Thermosetting Resin Conduit

  • 358.24 Electrical Metallic Tubing

342.30(A) Securely Fastened. A new exception to (A) allows intermediate metal conduit to be fished where securing is impracticable. Fishing is only permitted for unbroken lengths of conduit without couplings in the concealed space. Electrical metallic tubing and flexible conduit have already been permitted to be fished in concealed work in finished buildings or in prefinished wall panels. In each of these articles, the requirement and exception can be found in Section XXX.30(A).

344.28 Reaming and Threading. PVC-coated RMC is often used in areas subject to corrosion. New text was added to this section to require that the manufacturer’s instructions be followed when threading PVC-coated RMC to prevent damage to the exterior coating. An informational note was added that references NECA 101, Standard for Installing Steel Conduits (RMC, IMC, EMT), which provides information on threading PVC-coated RMC.

Flexible bus is permitted to be run through fire walls, partitions, floors or ceilings as long as the 300.21 fire stop requirements are followed.

352.10 Uses Permitted. Changes were made in 352.10 to clarify some uses of PVC conduit. It is permitted to be encased in concrete. A new (K) clarifies requirements for use in areas where subject to physical damage.

353.48 Joints. Section 353.48 was revised to require joints of high-density polyethylene conduit type HDPE to be made using a manufacturer’s identified method. It also prohibits heat fusion or butt fusion.

358.10 Uses Permitted. EMT is now permitted in direct burial applications where it is used with fittings identified for direct burial. It is also recognized for manufactured wiring systems as permitted in 604.100(A)(2).

362.10 Uses Permitted. Section 362.10(2) was revised to clarify that ENT is permitted to be installed in combustible or noncombustible buildings where the walls, floors and ceilings meet the finish rating. The mandatory reference to NFPA 13 was changed to an informational note reference. Section 362.10(6) was split into two sections to separate requirements for installations in poured-concrete floors, ceilings, walls and slabs from those where the EMT is embedded in concrete slabs.

370.18 Flexible Bus Installation. The requirements for cable bus installation have been simplified. The requirements for fire stops now align with the fire stop requirements for cable trays. This change makes it clear that flexible bus is permitted to be run through fire walls, partitions, floors or ceilings as long as the 300.21 fire stop requirements are followed. The previous requirement for curbs at floor penetrations was deleted because cable bus is permitted in wet locations.

370.120 Marking. The requirements for flexible bus marking were revised. Cable bus systems require two types of markings. The nameplates at the terminating ends identify the manufacturer and the maximum diameter, number, voltage rating and ampacity of the conductors installed. The second identification required is a marking that will facilitate compliance with the manufacturer’s assembly instructions. Nameplates are required at each terminating end of the system identifying the manufacturer and the ratings, and are required to be visible after installation.

404.1 Scope. The scope of Article 404 was revised to make it clear that the article only covers switches that are connected to the structure’s wiring. It does not cover battery-powered wireless control devices. At the second draft stage, a new informational note was added that references 210.70 for information related to branch circuits, including switches or listed wall-mounted control devices. Section 210.70 provides requirements for the location of lighting outlets, and now prohibits the switch or control device for the required lighting to rely exclusively on a battery unless a means is provided for automatically energizing the lighting outlets on battery failure.

404.14 Snap Switch Terminals. Section 404.14(D) was created to address the requirements for termination of conductors to the terminals of snap switches. Terminals of 15A and 20A snap switches that are not marked “CO/ALR” are permitted to be used to terminate copper or copper-clad aluminum conductors only. If the switches are marked CO/ALR, they are also permitted to be used with copper or copper-clad aluminum conductors, but can also terminate aluminum conductors. This section also points out the push-in terminals of snap switches are only permitted to be used on 14 AWG copper conductors. They are not permitted to be used on 12 AWG conductors. They are also prohibited for use with aluminum conductors or copper-clad aluminum conductors. Other sizes or types of conductors would have to be connected to the screw terminals of switches.

404.16 Reconditioned Equipment. Lighting, dimmer and electronic control switches are not permitted to be reconditioned.

404.30 Switch Enclosures with Doors. Doors of enclosures for switches that provide access to live parts when opened must be constructed so that either a tool or other approved means is necessary to open the door if the switch is in the closed position.

406.3(C) and (D) Receptacle Rating and Type. The title of 406.3(C) has been changed to CO/ALR Receptacles, which can be used for direct connection of aluminum conductors. Section 406.3(D) has been added to cover requirements for termination of conductors to receptacle terminals. Screw terminals on 15A and 20A receptacles not marked CO/ALR are permitted to be used with copper or copper-clad aluminum conductors only. Screw terminals marked CO/ALR are permitted to be used with copper, aluminum or copper-clad aluminum conductors.

406.4 General Installation Requirements. The requirements for replacement receptacles were modified. GFCI replacement receptacles are now required to be listed. Listed tamper-resistant receptacles are required as replacements if they are required elsewhere in the Code. However, if a nongrounding-type receptacle is replaced with another nongrounding-type receptacle, a tamper-resistant replacement is not required. There are no nongrounding-type, tamper-resistant receptacles available.

Similarly, if aluminum branch-circuit conductors connect to a CO/ALR receptacle that is being replaced with another CO/ALR receptacle, a tamper-resistant type receptacle is not required because none are available. GFPE receptacles are now required as replacements, where requirements exist elsewhere in the Code.

406.9 Receptacles in Damp and Wet Locations. In damp and wet locations, hinged covers of outlet box hoods are now required to open 90 degrees from the opened to closed position, unless they are not designed to open that far. Those outlet box hoods not capable of opening 90 degrees must be capable of opening fully. Receptacles of 15A and 20A, 125V and 250V installed in wet locations are required to be weatherproof, whether or not the attachment plug is inserted. Other receptacles are now required to be weather-resistant. There is a slight difference in application for receptacles that are attended while in use, which require a weatherproof enclosure when the attachment plug is removed.

The bathtub and shower space requirements have been revised and clarified to include the space inside the tub or shower and below the bathtub rim to the floor. It does not include space separated by a floor, wall, ceiling, door, window or fixed barrier.

A new exception was added for weight-supporting ceiling receptacles (WSCR) in damp locations complying with 410.10(D). A WSCR is a receptacle used to connect luminaires and ceiling fans. They are not interchangeable with receptacles for cord- and plug-connected equipment.

A new exception was added to permit a single receptacle for an electronic toilet or bidet in dwelling units, provided the receptacle is not located in the space between the toilet and the bathtub or shower.

About the Author

Mark Earley

Mark Earley, P.E., is an electrical engineer. Retired from the National Fire Protection Association, he was secretary of the National Electrical Code Committee for 30 years and is president of Alumni Code Consulting Group.

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