Metallic Outlet Boxes (QCIT) for use in fire-resistant rated assemblies All UL Listed single- and double-gang metallic outlet and switch boxes with metallic or nonmetallic cover plates may be installed in bearing and nonbearing wood stud and steel stud walls with fire rating not exceeding 2 hours. These metallic boxes
are not required to be marked specifically as suitable for use in fire-resistant rated assemblies. Metallic boxes located on opposite sides of walls or partitions
are intended to be separated by a minimum horizontal distance of 24 in. This minimum separation distance between boxes may be reduced when Wall Opening Protective Materials (QCSN) (commonly known as putty pads) are installed according to the requirements of their Classification. Putty pads other than those installed on the outer surfaces of a metallic box prior to installation of the wall are also available. UL Classified putty pads, also known in industry as box inserts, are for installation on the inside back surface of the box. There are also putty pads, known in industry as gaskets, available for application under the wiring device cover plate.
