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”.

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.


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”.