Switch faceplates made of nonmetallic insulating, noncombustible material must generally not be less than what thickness?

• A. 1.0 mm (0.039 in)
• B. 3.0 mm (0.118 in)
• C. 6.0 mm (0.236 in)
• D. 2.54 mm (0.100 in)

Answer: (D)

The main idea is that a switch faceplate needs enough material to stay secure and durable around the mounting screws and the switch opening. A thickness of 2.54 mm (0.100 in) provides enough rigidity and mass to resist cracking, bending, or wear at the screw holes, while still fitting standard mounting hardware. Lighter options, like 1.0 mm, are prone to cracking or deforming under screw torque or impact. Much thicker plate thicknesses, such as 6.0 mm, add unnecessary bulk without added safety benefits in normal use. So 2.54 mm is the practical minimum that ensures durability and reliable mounting.