312.10 Screws or Other Fasteners 

Overview 

Manufacturers of power cabinets, cutout boxes, and meter socket enclosures typically provide specifications regarding the type, quality, and length of screws and fasteners required to secure components inside their products. However, these specifications or recommended screw types may not always be readily available to end users. In such cases, it is crucial to adhere to the guidelines outlined in Section 312.10 of NEC 2023 to ensure that the chosen screws or fasteners do not compromise the electrical connections within the enclosures or cause mechanical issues such as vibrations or loose hardware. This update aims to provide clear guidance on the proper utilization of screws and other fasteners when installing various enclosure components.

Applying the 2023 Code 

The proper selection of screws and fasteners is crucial for maintaining the safety and reliability of electrical systems, especially when tightening covers or installing components within power cabinets, cutout boxes, and meter socket enclosures. Using the correct type, size, and quality of screws and fasteners ensures not only the secure fastening of enclosures but also preserves the integrity of electrical connections within them. Loose or improperly tightened screws and fasteners can lead to various issues, including vibration, loosening of covers and connections, loss of hardware, and compromised electrical connections. If left unaddressed, these issues can pose significant safety hazards over time. 

It is crucial to select and secure screws and fasteners in accordance with the specifications provided by the manufacturer. In situations where these specifications are not readily available from the enclosure manufacturer, adherence to standardized industry guidelines becomes essential. Previous editions of the NEC did not provide clear guidance in such cases, resulting in confusion and the adoption of non-standard practices. To address this issue, the 2023 edition of the NEC introduced a new Section 312.10, which outlines guidelines for tightening and installing various enclosures. This addition ensures the proper and safe installation of enclosure covers and components. 

What’s New for the 2023 NEC? 

The table below presents a comparison between the 2020 NEC and the 2023 NEC regarding Section 312.10.