334.3 supporting nm cable

[Dixonchad]

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?

 

[Dennis Alwon]

The box connector is not support. You need IMO a staple within 12" of the light

334.30 Securing and Supporting. Nonmetallic-sheathed
cable shall be supported and secured by staples, cable ties,
straps, hangers, or similar fittings designed and installed so
as not to damage the cable, at intervals not exceeding 1.4 m
(41⁄2 ft) and within 300 mm (12 in.) of every outlet box,
junction box, cabinet, or fitting. Flat cables shall not be
stapled on edge.

 

[Dennis Alwon]

Let me get this straight. Are you running exposed nm cable in the ceiling trusses that will not be covered up? Is this a finished project?

334.15 Exposed Work. In exposed work, except as provided
in 300.11(A), cable shall be installed as specified in
334.15(A) through (C).
(A) To Follow Surface. Cable shall closely follow the surface
of the building finish or of running boards.
(B) Protection from Physical Damage. Cable shall be
protected from physical damage where necessary by rigid
metal conduit, intermediate metal conduit, electrical metallic
tubing, Schedule 80 PVC conduit, Type RTRC marked
with the suffix -XW, or other approved means. Where passing
through a floor, the cable shall be enclosed in rigid
metal conduit, intermediate metal conduit, electrical metallic
tubing, Schedule 80 PVC conduit, Type RTRC marked
with the suffix -XW, or other approved means extending at
least 150 mm (6 in.) above the floor.

 

[Dixonchad]

Yes this will be a finished product. The trusses will be exposed. It just seems redundant to place a staple within 12 inches of the light fixture. While using 3/8 box connector. 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

 

[infinity]

So these cables will span the trusses?

 

[Dennis Alwon]

Yes this will be a finished product. The trusses will be exposed. It just seems redundant to place a staple within 12 inches of the light fixture. While using 3/8 box connector. 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

I think you would have to run a board in order to follow the surface of the structure. It would like like hell if you just had NM cable running from truss to truss

 

[Dennis Alwon]

So these cables will span the trusses?

That is what I am getting out of it

 

[don_resqcapt19]

Yes this will be a finished product. The trusses will be exposed. It just seems redundant to place a staple within 12 inches of the light fixture. While using 3/8 box connector. 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

It would probably be quicker and cheaper to run EMT between the fixtures. There is an exception for EMT that permits the first support to be 5" away from the fixture.

 

[Dennis Alwon]

It would probably be quicker and cheaper to run EMT between the fixtures. There is an exception for EMT that permits the first support to be 5" away from the fixture.

I agree.. That was my thought originally. I couldn't believe the home owner or builder would allow exposed NM

 

[Dixonchad]

Ok thanks for the push. Wanted to make sure i had enough staples. This job was a labor only installation and this guy was a retired lineman from the power co and has designed everything some of which we didnt agree on. He doesnt want to run a board or use emt. Ceiling height is 18 ft with 12 ft doors and its being used for a parking garage for a boat jet skis and a camper. Why this big? I have no idea. Im comfortable with saying that the nm cable wont be damaged after the work is complete. This is a workshop garage for him to tinker with and store toys. We explained from square 1 that we was concerned with spanning the trusses but he didnt want to use the additional wire that would be necessary to run the cable down to the nearest reinforcement board or rat board. And he definitely didnt want to utilize emt. It will be interesting to see what the inspector says tomorrow. Will post a follow up.

 

[iwire]

Ok thanks for the push. Wanted to make sure i had enough staples. This job was a labor only installation and this guy was a retired lineman from the power co and has designed everything some of which we didnt agree on. He doesnt want to run a board or use emt. Ceiling height is 18 ft with 12 ft doors and its being used for a parking garage for a boat jet skis and a camper. Why this big? I have no idea. Im comfortable with saying that the nm cable wont be damaged after the work is complete. This is a workshop garage for him to tinker with and store toys. We explained from square 1 that we was concerned with spanning the trusses but he didnt want to use the additional wire that would be necessary to run the cable down to the nearest reinforcement board or rat board. And he definitely didnt want to utilize emt. It will be interesting to see what the inspector says tomorrow. Will post a follow up.

:lol:

What the customer wants and what the NEC allows are not the same.

The installation you describe should fail inspection for NM being run exposed in other than a dwelling unit, for lack of supports and not following the building surface.

 

[big john]

Why wouldn't this fall under the allowance for 320.23 (redirected from 334) that plainly permits running on the tops of joists in accessible roof spaces?

Seen many jobs like that pass inspection.

 

[iwire]

We really need to know what code cycle the OP is on.

Depending on that NM may not be allowed to be run exposed at all.

 

[kwired]

It would probably be quicker and cheaper to run EMT between the fixtures. There is an exception for EMT that permits the first support to be 5" away from the fixture.

Exactly what I would have done, and would have cost less then using NM cable, even if you push the support rules around.

I agree.. That was my thought originally. I couldn't believe the home owner or builder would allow exposed NM

Sounds like HO is the engineer on the project

Why wouldn't this fall under the allowance for 320.23 (redirected from 334) that plainly permits running on the tops of joists in accessible roof spaces?

Seen many jobs like that pass inspection.

They are not concealed behind a 15 minute finish, may still be allowed if this is a dwelling accessory building though.

 

[iwire]

They are not concealed behind a 15 minute finish, may still be allowed if this is a dwelling accessory building though.

Which depends on what year NEC they are under.

 

[big john]

...They are not concealed behind a 15 minute finish, may still be allowed if this is a dwelling accessory building though.

Fair point. I assumed this was a man-cave garage at their house.

 

[iwire]

Fair point. I assumed this was a man-cave garage at their house.

Even if it is exactly that, there is at least one, maybe two code cycles that exposed NM would be a violation. They added the 'dwelling accessory building' to loosen things up a bit.

 

[newservice]

Funny, after the OP realized the homeowner was telling him which wiring method to use, we haven't heard back from him.

 

[newservice]

Why wouldn't this fall under the allowance for 320.23 (redirected from 334) that plainly permits running on the tops of joists in accessible roof spaces?

Seen many jobs like that pass inspection.

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.

 

[kwired]

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.

Either way there needs to be securement within 12" of the luminaires, boxes, etc.