What requirement applies to snap switches, including dimmer switches?

Snap switches, including dimmer switches, must provide a means to connect to grounding conductors to ensure safety and proper operation. This requirement is crucial because grounding provides a path for electrical current to flow safely to the ground in the event of a fault or malfunction, reducing the risk of electric shock or fire.

By having a connection for grounding conductors, these switches help protect the circuit from faults and enhance the overall safety of the electrical system. The grounding connection can also help in protecting sensitive electronic components that may be connected to the switches.

In contrast, options that suggest these switches can operate without equipment grounding, do not require faceplates, or must be placed in series do not emphasize the important safety aspect that grounding connections bring to electrical devices. Therefore, providing a means for grounding is a fundamental requirement for the safe installation and functional reliability of snap switches and dimmer switches.