What NEC® section permits a surface extension from a flush-mounted device box to be made by installing an extension ring?

The correct choice relates to NEC® section 314.23, which addresses the installation of extension rings on flush-mounted device boxes. This section specifies that when a surface extension is created, it must comply with certain criteria to ensure safety and functionality.

According to NEC® section 314.23, an extension ring can be used to extend a box to accommodate devices that require a degree of surface mount. This allows for the proper securing of covers and devices while maintaining the necessary volume for wiring and connections. The use of extension rings also ensures that the overall installation remains stable and in compliance with the code, reducing the risk of issues such as improper fit, overheating, or lack of accessibility for maintenance.

This section shows the importance of following proper procedures and requirements in electrical installations to uphold safety standards mandated by the National Electrical Code.