Commercial Work Questions

[623merlin]

I'm not sure about your city/state revisions to the NEC, but here in Phoenix, AZ, Romex is NOT allowed in commercial buildings. Whatch your strapping of AC cable, within 6" of a junction/connector and at least every other stud/joist (48" max between supports) there after. Use the all-in-one snap-in AC connectors, thery are must faster to install and the anti-short is built-in. If you are running alot of AC or you have limited experiance running it, invest in a rotary AC cable splitter splitter. It will save you time and lots of frustration not to mention saving you from excessive trouble-shooting later on.

Your 2x4 flouresent lighting fixtures (trouffers) must be mechanicaly connected to the grid via the sheet metal/bend out clip in the franes of the fixtures, or separate screw on clips provide (most of the time) in your fixture hardware or by use of (2) two screws per end of the fixture. Your city / state my require the use of one of these methods over the other (can't go wrong with screws, just not too long or you will screw thought the tombstones). The grid wires (siesmic wires) must be suported separately from the ceiling wire and cannot attach to the grid or be used to support anything other than the fixture itself. You must attach a minimum of (2) wires per fixture on opposite/ diagonal corners. This is a good time to consider your emergency lighting. At battery back-up / emergency balast can kill two birds with one stone and emergency fixture assemblies (Troffers, with whips, ballasts and lamps factory installed) do not cost much more than your standard 2x4's.

What is the square footage of the building? I'm in a small TI right now, only 40,000 Sqft.

 

[mkgrady]

What is the square footage of the building? I'm in a small TI right now, only 40,000 Sqft.[/QUOTE]

It's only 2,000 sf. NM is allowed in Massachusetts above suspended ceiling in commercial work. But I didn't know that yesterday.

 

[JohnE]

Running (stapling in this case) NM along the framing members seems reasonable but I don't get the logic of running boards. Can't I just staple perpendicular across the bottom of the ceiling joists? For that matter wouldn't doing it at 45 degree or any angle be OK? Seems like above drop ceiling these methods would be safe and neat. Am I reading this wrong?

IMO, that wouldn't folow the surface of the framing member(s). What you describe is exactly what MA wants to avoid, while still permitting the use of NM.

 

[mkgrady]

IMO, that wouldn't folow the surface of the framing member(s). What you describe is exactly what MA wants to avoid, while still permitting the use of NM.

I agree with following the surface of the joists. They are the framing members that exist. I'm just questioning running across joists. I assumed MA wanted to avoid the unsupported NM wiring that is common above drop ceilings. Sometimes the rats nest is really bad. Stapling across joist bottoms or tops seems reasonable in that space. The hazards of doing it elsewhere seem to be non existant up there. There is nothing up there. No room to walk, no floor. Drilling the joists seems like an unnecessary weakening of the structure and installing running boards up there seems like a lot of extra effort for no gain.