Powder filling Powder filling:
The marking for this protection technique is "q". is defined as a type of protection where electrical parts capable of igniting an explosive atmosphere are fixed in position and completely surrounded by filling material (glass or quartz powder) to prevent the ignition of an external explosive atmosphere.

This method is unique to zone-classified areas. It is used primarily for protection of fuses and for filling junction boxes that contain wire connections.

LocationsLocations:
This protection technique shall be permitted for equipment in Class I, Zone 1 or Zone 2 locations.

NOTE: This is an unformatted excerpt from our online fire protection training library.