This publication covers guidelines for selection and installation of general purpose and specialty metallic, nonmetallic, and composite outlet boxes such as device boxes, fixture boxes, and junction boxes; extension rings; covers; and flush device cover plates. The boxes addressed in these guidelines are intended for use in ordinary, non-hazardous locations. With the exception of masonry boxes and some multigang boxes and floor boxes, the boxes addressed in these guidelines are limited to 1650 cm³ (100 in³) internal volume.