404.9 Provisions for General-Use Snap Switches.
(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.
Exception to (B): Where no grounding means exists within the snap-switch enclosure or where the wiring method does not include or provide an equipment ground, a snap switch without a grounding connection shall be permitted for replacement purposes only. A snap switch wired under the provisions of this exception and located within reach of earth, grade conducting floors, or other conducting surfaces shall be provided with a faceplate of nonconducting, noncombustible material.
[This message has been edited by iwire (edited 10-08-2005).]