One of the acceptable “protection techniques” for electrical enclosures within a Hazardous Location is to “pressurize the enclosure.” Here are the three (3) Types of Pressurized Enclosures and the HAZLOC they are permitted to be used, and their design basis: NFPA 70, 500.7, (D) Purged and Pressurized. This protection technique shall be permitted for equipment in...