Code Change Summary: Revised code language on pendant boxes supported by cords and cables.

Section 314.23(H)(1) covers installations where a pendant box is supported from a multiconductor cord or cable. Pendant box installations are often used to provide receptacles in locations of merchandise display that are frequently changed, or in other locations where cord and plug connected utilization is frequently interchanged.

In a pendant installation, there are two locations where support is needed. One point is where the cord or cable originates and connects to the branch circuit conductors overhead, and the other point is where the pendant box is installed at the bottom of the hanging cord or cable.

The first point of support overhead is addressed in NEC^® Section 400.14 which requires flexible cords and flexible cables to be connected to devices and fittings so that tension is not transmitted to joints or terminals.

The second point of support is for the outlet box which is covered in NEC^® Section 314.23(H)(1).

In the 2023 NEC^®, the language on the proper support of pendant boxes has been updated to align with the language in the UL Guide Information for UL Product Category Code QCRV which covers Outlet Bushings and Fittings.

The previous code language required pendant boxes to be supported in an approved manner to protect the conductors against strain and gave an example of a code compliant installation method which is a strain-relief connector threaded into a pendant box equipped with a hub.

In the 2023 NEC^®, a pendant box must still be supported from a multiconductor cord or cable in an approved manner that protects the conductors against strain, but the previous example of how to accomplish it was changed into mandatory language. Now, if the method chosen to provide proper pendant box support is a connection to a pendant box equipped with a hub, the connection shall be made with a listed cord grip attachment fitting that is marked for use with a threaded hub.

It would be a mistake and misapplication of the product to use a strain relief grip with straight threads for a pendant box hub that has internal tapered threads.

Listed male threaded strain relief fittings that are intended to be secured to boxes equipped with threaded hubs have tapered National Pipe Threads (NPT) which will match the internal female threads on the pendant box hub entry. These listed strain relief fittings will be marked on the smallest unit shipping carton with installation information for the installer to ensure that these fittings are only used for a pendant box with a threaded entry or hub.

The Guide Information for UL Product Category Code QCRV is clear that male fittings not provided with a locknut, that are intended for securement to a threaded hub, are only to be used for securement to a threaded hub. These fittings are not intended to be used to support a sheet metal box through a knockout without the use of a hub.

The basic standard used to investigate strain relief type fittings is UL 514B, ”Conduit, Tubing, and Cable Fittings”.

UL 514B clause 5.8.1.5 states that a fitting with external threads and is intended to be connected to a sheet metal box shall be provided with a locknut.

UL 514B clause 8.1.5 states that a locknut provided as part of a fitting shall be tested as part of the fitting and shall comply with the applicable requirements for that fitting.

Below is a preview of the NEC^®. See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2023 NEC^® edition of NFPA 70.