What is the difference between grounding and non grounding switches? What application would require one or the other? For example, P&S makes 120VAC, 15A toggle switches in grounding (660-IG)and nongrounding (660-I) types.
A grounding switch has a means to attach an equipment bonding conductor.
Take a look at section 404.9 (B). The requirement for grounding of switches was added to the 1999 NEC. A non grounding switch can be used as a replacement.
A grounding switch would be required with a nonmetallic box so that you can provide a means to ground a metal face plate. This is required by 404.9(B). A switch with a metal yoke can still be used with a grounded metal box because 404.9(B)(1) permits the use of the switch mounting screws as the grounding means.
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