Securing NM Cable 8 inches or 12 inches?

Is there a difference in method to secure NM cable depending on the type of outlet box is used? I thought there was a 12 inch rule but then I heard that if a non-conducting box is used that changes to 8 inches.


I haven’t heard that one Greg. I also follow the 12" rule.

I would be more concerned with the non-protected, incadescent lightbulb in a storage “closet”.

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Hi Jeff, The “Closet” is actually an attic space with storage. I thought about that. There is no rule on protection of lights in attic spaces, but there is in “closets”. This was in a knee wall storage area in a cape cod home. Had to crawl in for access. That’s why I considered it as an attic.

That is technically correct, but, we both know we can report based upon safety. I would consider that location more of a potential for hazard than a basic clothes closet. JMHO.

Hopefully someone has an answer to the 8"/12" question.

Is this the exception you are referring to;

NEC 314.17© Exception: Where nonmetallic-sheathed cable or multiconductor Type UF cable is used with single gang boxes not larger than a nominal size 57 mm x 100 mm (2-1/4 in. x 4 in.) mounted in walls or ceilings, and where the cable is fastened within 200 mm (8 in.) of the box measured along the sheath and where the sheath extends through a cable knockout not less than 6 mm (1/4 in.), securing the cable to the box shall not be required. Multiple cable entries shall be permitted in a single cable knockout opening.

That must be it. So the way I interpret this applies to the way the cable is secured in the box which is something that we will not “see”.

I am familiar with non-metallic boxes and most usually have a built-in “spring-type” clamping method that would prevent the cable from pulling loose anyway. So securing the cable(s) within 12 inches of the box is OK.

I have also seen non-metallic boxes that have a knock-out without any internal clamping method. In those cases, the cable needs to be secured within 8 inches of that style of non-metallic box.

I’ve attached some examples for help.


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Good post Greg.

Either way guys, the NM is not secured as required and the light will scorch teh OSB and may start a fire if left on too long IMHO.

Report it and move on.

Off Topic…but that’s just another wonderful reason that 100 watt light bulbs are no longer being manufactured…:shock:

I’m with Greg on the light. No code prohibits it and it’s not a fire hazard. I’m an extremely thorough inspector, but when something’s in question I often defer to the axiom “don’t be a pinhead”.

I found this in the InterNACHI practice questions.

That answer is wrong. The cable needs to be secured to the panel with a proper cable clamp. It would be secured within 12 inches from the panel.