The electrician must make sure that each individual knob-and-tube conductor enters the box through a separate (individual) hole. If flexible tubing is used to encase the knob-and-tube conductors, the tubing must extend from the last insulating support to at least 1/4 inch inside. Where metal boxes or conduit bodies are installed with messenger-supported wiring, open wiring on insulators, or concealed knob-and-tube wiring, conductors shall enter through insulating bushings or, in dry locations, through flexible tubing extending from the last insulating support to not less. NEC Article 314 establishes requirements for the installation and use of electrical boxes, conduit bodies, fittings, and handhole enclosures. A conduit body is a removable-cover section of a conduit system that provides access at junctions or termination points. Article 314 applies to: These. The outcome your boss wanted was to ensure that Section 300. 4 (A) (1) was met, in that the closest edge of the hole was at least 1 ¼” away from the closest edge of the stud. That way, that pesky drywall screw would have less of a chance of damaging the newly installed wire that was run through the. The applications involve the bonding of 15kV transformer housings and structural steel I-Beams & columns for lightning protection, grounding & bonding. I'm appoligize if I appear to have my mind made up. You must use approved materials, choose the right size box, and make sure you ground everything correctly. Keep in mind that Article 300 doesn't apply to the internal parts of electrical equipment, nor does it apply to communications systems (except where.