Openings should not be drilled within 6 mm (1/4 in. ) of an edge or corner of a box or conduit body, or a knockout or formed conduit hub, or any formed screw boss or raised area inside the box or conduit body. Wiring methods, components, and equipment for general use. General requirements - Electrical continuity of. It is used to facilitate cable pulling, maintenance, and jointing for electrical and fiber optic cables. Article 314 applies to: These. Abstract: The design, installation, and protection of wire and cable systems in substations are covered in this guide, with the objective of minimizing cable failures and their consequences. For installations of listed drain fittings, larger openings are permitted to.