All hand-held powered platen sanders, grinders with wheels two (2) inches diameter or less, routers, planers, laminate trimmers, nibblers, shears, scroll saws, and jigsaws with blade shanks one-fourth (1/4) of an inch wide or less may be equipped with only a positive "On-Off" control.
All hand-held powered drills, tappers, fastener drivers, horizontal, vertical, and angle grinders with wheels greater than two (2) inches in diameter, disc sanders, belt sanders, reciprocating saws, saber saws, and other similar operating powered tools shall be equipped with a momentary contact "On-Off" control and may have a lock-on control provided that turn off can be accomplished by a single motion of the same finger or fingers that turn it on.
All hand-held powered tools, such as circular saws, chain saws, and percussion tools without positive accessory holding means, shall be equipped with a constant pressure switch that will shut off the power when the pressure is released.
Exception: This paragraph does not apply to concrete vibrators, concrete breakers, powered tampers, jackhammers, rock drills, and similar hand operated power tools.
W. Va. Code R. § 36-23-30