General-use dimmer switches are restricted to controlling what type of load?

General-use dimmer switches are specifically designed to control permanently installed incandescent luminaires. This limitation is due to the characteristics of incandescent lighting, which includes the ability to dim smoothly across a range of brightness levels without flickering or operational issues when used with compatible dimmer switches. Incandescent bulbs provide a constant resistance, allowing dimmers to effectively manage their current flow.

While LED lights can also be dimmed using specific dimmer switches, not all dimmers are compatible with LED technology. LEDs require dimmers that are designed specifically for their unique electronic circuitry. Recessed flood lights and temporary fixtures might be dimmable when using appropriate equipment, but they do not align with the standard restrictions placed on general-use dimmers, which focus predominantly on permanent installations. Therefore, the best choice in this context is the option that pertains to permanently installed incandescent luminaires.