Routing of cables with finished ceiling

[yousah]

We're building a garage in the back yard and will have a finished drywall ceiling along with a floored attic over 12" ceiling joists.

I was trying to get some general idea of how most folks end up running their electrical cable in the attic. We can use non-metallic Romex and I was thinking of just keeping it routed around the edge of the finished attic floor and dropping down through the top plates as needed. I'll have to look, but I think the NEC requires some sort of framing around the cable itself when surface routed.

My thought was that it would be too much of a hassle to try and run the wiring anywhere near the ceiling joists that will be enclosed on top and bottom.

Does that sound like a reasonable way to do it? Thanks!

 

[Slowgsr]

Just drill the joists, romex needs to be protected from mechanical damage. Ie no surface mounting. If you want to run surface use bx, but surface mounted anything is ugly

 

[Mustang51js]

You can get away with running the wires over the beams where the roof line and floor because it's not accessible

 

[Slowgsr]

You can get away with running the wires over the beams where the roof line and floor because it's not accessible

But it's going to be a finished space, I guess it depends on the pitch of the roof.

The op, you could run them like that then just close in that cavity with a 2x4 or 2x6 on its edge. If that's acceptable in appearance to you

 

[wyliesdiesels]

Just drill the joists, romex needs to be protected from mechanical damage. Ie no surface mounting. If you want to run surface use bx, but surface mounted anything is ugly

Not true. NM-b can be surfaced mounted as long as its not subject to damage.

Also, MC(metal clad cable- has conductors including an EGC), and BX(which is no longer made; its now called AC- armored cable which has a grounding strip but no EGC) all have the same protection requirements as NM-b...

If its in an area where it might get damaged FMC(flexible metal conduit) aka greenfield, is a better choice...but u will have to purchase wire to go with it...

 

[Slowgsr]

'Subject to mechanical damage' is very subjective to the inspector, and in many cases nmd90 is subject to mechanical damage far more easily the ac90 mounted in the same place.

Regardless of code, it's always at the Inspectors discretion, and it's an argument you won't win.

 

[yousah]

My first thought was to run them right in the corner where there ceiling joists and rafters meet each other. I could easily put some sort of protection in front of them like a piece of plywood.

I've always liked the 'hidden' option of going through the joists, but it'll be awhile before I get all my fixtures and outlets where I want them, and I would inevitably have to do some cable routing after the ceiling and attic floor are up. So I'm primarily thinking about what option gives me the most flexibility.

I like the mention of armored cable. Perhaps I'll use that in the attic.

 

[nafterclifen]

The attic above my garage was unfinished. Most of the cables ran from the panel in the garage, down one side laying on top of the joists. Some ran to the other side of the garage, over top of a beam. Being that I was insulating it and putting down a floor, I had to clean it up. I didn't drill ANY joists. I had to use more wire but I ran everything around the perimeter and "hung" them.

 

[tfi racing]

The attic above my garage was unfinished. Most of the cables ran from the panel in the garage, down one side laying on top of the joists. Some ran to the other side of the garage, over top of a beam. Being that I was insulating it and putting down a floor, I had to clean it up. I didn't drill ANY joists. I had to use more wire but I ran everything around the perimeter and "hung" them.

So its safe to assume you have de-rated all those cables in those larger bundles accordingly...

 

[Norcal]

Routing cables in that manner is considered "bundling" as noted by TFI Racing.

 

[nafterclifen]

Before I "bundled" them, they were all laying in a pile over the joists.

What's the difference?

 

[Mustang51js]

I wouldn't worry about it