National Electrical Installation Standards

Standards as High as Your Own

Thursday, September 7, 2023


Hello CQD, I'm a general contractor in Phoenix where we surface mount our main panels outside. Typically, we bring the branch-circuit NM Cables into the backside of the panel, thru a large, bushed knockout. Section 312.5(C) requires that each NM cable be secured to the panel enclosure. We screw (secure) the panel to a horizontal block of wood between the studs with 2 appropriate screws. We staple (secure) the NM Cable on the backside of the same block of wood before we bring them into the panel thru a large knockout bushing. Does this meet the code? If it meets the letter of the code, does it meet the intent as well? Best, Michael Stegge


Hello Michael, thanks for participating in the CQD. The installation of several cables bunched together and run through a large knockout or chase nipple is prohibited by Section 312.5(C). The installation you are describing in the question would not meet the intent or letter of the code. Individual cables clamps or connectors are required to be used with only one (1) cable per clamp or connector, unless the clamp or connector is identified and listed for use with more than a single cable.

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