When is it acceptable to use flexible conduits with boxes?

The use of flexible conduits with boxes is acceptable when the installations comply with NEC requirements and are suited for the environment. This ensures that the installation adheres to safety standards and is appropriate for the specific conditions where the wiring is being installed.

Flexible conduits are often utilized in areas where movement, vibration, or the need for some degree of adaptability in the installation exists. For example, in industrial settings or locations that require access to equipment, flexible conduits allow for greater ease in maintenance and modifications. The determination of suitability also considers factors such as temperature, moisture, and exposure to chemicals, which are key to ensuring both safety and durability in electrical installations.

The other options focus on aesthetics, specific applications, or temporary situations, which do not encompass the overall safety and compliance aspects that the NEC emphasizes. Compliance with the National Electrical Code ensures that all aspects of electrical safety, functionality, and environmental considerations are accounted for in the installation of flexible conduits.