334.3 supporting nm cable

[Dennis Alwon]

I think the OP said he wants to run on the face of the rafters to lighting, not the top of the attic floor joists.

The face of board is one thing but I believe he also wanted to run perpendicular to the joist without a board

So we would have to run the rat Board from truss to truss since the light fixtures are 8 foot long and does not give us any room to place a staple without adding a scab board or rat board

 

[MasterTheNEC]

Hello I'm working on a pole frame building that have trusses four foot on Center. We have installed 8 foot 4 Lamp LED light fixtures that are utilizing the tube style lamp spaced 12 feet apart from end-to-end. So that leaves me with two trusses in between. The building contractor is not putting a finished ceiling up. My question has to do with stapling the Romex Wire that will run from light fixture to light fixture. We are obviously going to staple on each Truss. And we have NM box connectors on each end of the light. So i believe that I am with in 334.3 securing and supporting NM cable. Do I have to put a staple outside of each light fixture in addition to the NM box connector?

Greetings Dixonchad,

Assuming that all things considered and the structure meets all the initial aspects of Section 334.10(1), (2), (3). Since your installation is going to clearly be exposed you have to meet the intent of Section 334.15(A) and running it from truss to truss is not following the buildings surface nor have you expressed a desire to install running boards. Also in terms of the securing and supporting of Type NM-B Cable, you are required per Section 334.30 to supported and secured within 12 inches of these junction boxes or device boxes (which ever your installation calls for). I also do not believe that Section 334.30(B)(2) affords you any relief in your expressed installation.

with Type NM-B Cable, unlike as expressed for Type MC Cable in 330.30(D), where the connector/fitting is considered a cable support by the statement " For the purposes of this section, Type MC cable fittings shall be permitted as a means of cable support." Furthermore, that provision if construed as a connector being such a support would be unsupported by the fact the allowance only applies to One- Two, or multifamily dwellings and not their accessory buildings as the language stands now in the 2017 NEC.

While it could be argued (and I have no doubt it will) that the connector/fitting is the last cable support the current language, unlike it is stated in 330.30(D), is not so clear on that as of yet. The fittings for type NM-B Cable has not been evaluated as such a supporting component as has been done with Type MC and AC fittings in the past. So among the other issues that are not code compliant, that is my thoughts on the subject.

Hope it is helpful...and it is perfectly ok to agree to disagree with my thoughts.