A fused safety switch installed in a Class II Division 2 location shall be ___.

A fused safety switch installed in a Class II Division 2 location shall be ___.

• A. rated heavy-duty
• B. raintight
• C. dusttight
• D. rated general duty

Answer: (C)

In a Class II Division 2 location, the concern is preventing dust from entering electrical equipment to avoid ignition sources. A fused safety switch used there must have an enclosure that is dusttight, so no dust can ingress under normal service or abnormal conditions. This protects the internal components (like fuses and contacts) from dust buildup that could cause overheating, arcing, or ignition. The other ratings don’t address dust protection specifically: heavy-duty speaks to mechanical ruggedness, not sealing against dust; raintight protects against water entry, which isn’t the hazard in this scenario; general duty is a broad rating that doesn’t ensure dust containment. Therefore, dusttight is the appropriate requirement.

In a Class II Division 2 location, the concern is preventing dust from entering electrical equipment to avoid ignition sources. A fused safety switch used there must have an enclosure that is dusttight, so no dust can ingress under normal service or abnormal conditions. This protects the internal components (like fuses and contacts) from dust buildup that could cause overheating, arcing, or ignition.

The other ratings don’t address dust protection specifically: heavy-duty speaks to mechanical ruggedness, not sealing against dust; raintight protects against water entry, which isn’t the hazard in this scenario; general duty is a broad rating that doesn’t ensure dust containment. Therefore, dusttight is the appropriate requirement.