Code Change Summary: Section 314.23(F) exception 1 now permits an FS or FD single-gang device box or an explosionproof outlet box of any size to be supported by a single raceway.

SME commentary: In the 2026 NEC^®, exception 1 in Section 314.23(F) has been revised to expand the single-raceway support allowance to include FS and FD single-gang device boxes and explosionproof outlet boxes. Previously, the exception applied only to conduit bodies. The change recognizes the structural strength and hub-thread design of these box types, which make them suitable for single-raceway support.

Without the exception, the general rule in 314.23(F) provides specific limitations for raceway-supported enclosures containing devices, luminaires, or lampholders. Such enclosures must not exceed 100 cubic inches in volume, must have threaded entries or hubs, and must be supported by at least two threaded conduits that are wrench-tight to the box. Each supporting conduit must be secured within 18 inches of the enclosure. These provisions ensure that the raceway system provides adequate mechanical support without risk of the enclosure separating from the raceways and exposing conductors.

Exception No. 1 now permits a single rigid metal conduit (RMC) or intermediate metal conduit (IMC) to support a box or conduit body with one or more threaded entries, provided it meets at least one of the following conditions:

1. The conduit body is not larger than the largest trade size of the conduit.
2. The box is an FS or FD single-gang device box.
3. The box is a single-gang explosionproof outlet box of any size.

The addition of FS, FD, and explosionproof outlet boxes to the list recognizes that these enclosures are designed with thick walls and internal threaded hubs that provide a secure, wrench-tight raceway connection. The robust casting and hub design prevent the box from loosening under vibration or mechanical strain, maintaining a tight connection between the raceway and enclosure.

This revision improves installation flexibility, particularly in industrial, commercial, and hazardous (classified) environments where explosionproof and weatherproof FS or FD boxes are commonly used to house switches, receptacles, or lighting outlets. It allows electricians to support these boxes with a single raceway when permitted by the conditions of exception 1, eliminating the need for additional brackets or support means.

By expanding 314.23(F) exception 1, the 2026 NEC^® aligns the requirements for enclosures containing devices or luminaires with similar requirements in 314.23(E) for enclosures without devices. The change is consistent with the Code-Making Panel’s intent to simplify and clarify support methods for enclosures with threaded hubs that ensure adequate mechanical strength when these enclosures are mounted directly to a single raceway.

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 2026 NEC^® edition of NFPA 70.

2023 Code Language:

314.23(F) Raceway-Supported Enclosures with Devices, Luminaires, or Lampholders. An enclosure that contains a device, other than splicing devices, or supports a luminaire, a lampholder, or other equipment and is supported by entering raceways shall not exceed 100 in.³ in size. It shall have threaded entries or identified hubs. It shall be supported by two or more conduits threaded wrenchtight into the enclosure or hubs. Each conduit shall be secured within 18 in. of the enclosure.

Exception No. 1: Rigid metal or intermediate metal conduit shall be permitted to support a conduit body of any size, including a conduit body constructed with only one conduit entry, provided the trade size of the conduit body is not larger than the largest trade size of the conduit.

See the actual NEC^® for exception 2.

2026 Code Language:

314.23(F) Raceway-Supported Enclosures with Devices, Luminaires, or Lampholders. Enclosures that contain devices, other than splicing devices, or support luminaires, lampholders, or other equipment and are supported by entering raceways shall not exceed 100 in.³ in size. Enclosures shall have threaded entries or identified hubs and be supported by two or more conduits threaded wrenchtight into the enclosure or hubs. Each conduit shall be secured within 18 in. of the enclosure.

Exception No. 1: A single rigid metal or intermediate metal conduit shall be permitted to support a box or conduit body with one or more of the following entries:

(1) Conduit body of trade size not larger than the largest trade size of the conduit

(2) FS or FD single gang device box

(3) Single gang explosionproof outlet box of any size

See the actual NEC^® for exception 2.