404.9(B) Grounding. Snap switches, including dimmer and similar control switches, shall be effectively grounded and shall provide a means to ground metal faceplates, whether or not a metal faceplate is installed. Snap switches shall be considered effectively grounded if either of the following conditions is met.
(1)The switch is mounted with metal screws to a metal box or to a nonmetallic box with integral means for grounding devices.
(2)An equipment grounding conductor or equipment bonding jumper is connected to an equipment grounding termination of the snap switch.