Metacaulk® Box Guard™ is a single component fire rated insert for use with electrical boxes. It is inserted on the inside back wall of an electrical box, and is a highly intumescent firestop material. When exposed to fire, Metacaulk® BOX GUARD™ will expand forming a char that will seal off the opening and prevent the spread of flames and limit the temperature rise on the un-exposed surfaces.Metacaulk® BOX GUARD™ is applied by hand, and must comply with NEC 314.16 (for-merly 370.16) or other applicable codes. U.S. Patent No. 6,207,085 & 6,252,167.
Use Metacaulk® BOX GUARD™on inside back panel of electrical boxes to maintain the integrity of fire rated wall assemblies restrict-ing the passage of flames and limiting the temperature rise on the unexposed surfaces.When Metacaulk® BOX GUARD™is used as directed, the horizontal separation between outlet boxes on opposite sides of the wall may be less than 24 inches.