8 An open hole in a box, such as a mounting-screw hole, shall have no dimension larger than 6. 265 in), except that a pryout hole or slot may be provided in a knockout for 1 in or smaller trade size conduit, provided that the area of the hole or slot is. This guide covers everything you need to know about electrical box knockout sizes, including the types of knockouts, their applications, and how to select the correct size for your project. They provide pre-scored, removable sections that allow for the entry of conduits and cables while maintaining the structural integrity of the enclosure 1 3. The. The electrical industry has common conduit sizes. See conversion chart below: Form Up or Form Down? Choose the form direction based on whether the slug needs to. The family handyman has highlighted a type of box with threaded holes that make water-resistant connections possible. Fortunately, you don't have to overthink this decision. Made from durable polycarbonate plastic, the enclosures are molded with metric knockouts that can simply be removed with a screwdriver.
[PDF Version]