The question is: MUST you use troffers ("lay in fixtures") to provide light through a suspended ceiling?

I recently saw a home with a finished basement. A suspended ceiling was installed. for lighting, ordinary strip fixtures were installed to the 'hard' ceiling above, and lens panels were put in the grid underneath the fixtures.

(I always wondered why I always had to trim the home-center lenses a bit!)

Details of this specific installation aside, it made me wonder if there was anything wrong with the very concept.

Every home that I've seen has been done with striplights and a plastic panel below. It's pretty easy to see the unevenness of the light from above...I wonder if that's because the manufactured troffers do a better job of spreading out the light before it hits the lens.

Not sure I'd do it in my home. I don't see it as a code issue unless they were cord and cap connected. I have seen "cost conscious" versions of this that also include a reflector that almost fits the 2x4 space in a standard drop ceiling grid.

I have to agree with George. You may find a 110.3 IF there is any indication from the fixture (luminaire) mfg that the fixture is designed for surface mounting.

That may be considered 'pushing the envelope' but....ya never know.

I did this on an addition in my old house in Md (late 70s) and I would not do it again. I learned a lot of lessons on that project

The reason you have to trim the panels is they are actually 2x4 and the grid is 2x4 on center. You are trimming off the thickness of the T bar. YMMV it seems, some seem to be a tad smaller than 2x4 and go in without trimming.

Greg:

I think Reno was refering to using 'big box' lenses as replacements for 2x4 troffers. Basically, something that I can say 'been there, done that'!

Yes, I also had channel strips, with 'custom cut' lenses in our old house. And, I will not do that again.

I’ve seen that type of install a lot over the years, especially in older 1970’s kitchens and basements. I'm wondering if the manufacture states surface mounting only as mentioned, since the manufacture most likely doesn’t specify what particular surface is approved for mounting, I'm guessing that the suspended ceiling still wouldn't qualify as structural ceiling in this situation.

I am just talking about screwing a strip on the structural ceiling above the center of a 2x4 T bar hole and dropping a diamond molded lexan panel in there instead of a ceiling panel.

I wired a tree house for a family and they wanted me to pick out a fixture that would be safe and fitting for their kids. I hate picking out fixtures for somebody else. I ended up put strip lights between the ceiling joists and framed in a slot for a panel to slide in below the joists. I ordered a panel with the clouded sky printed on it. It looked pretty cool in the tree house, like a hole in the ceiling.

Hey Schenimann- Did you get a permit, an inspection and a C of O? ha ha ha

There is an unstated need for height when using T grid.

Whenever I've encountered it in homes, it's always in a DIY basement 'upgrade' designed to use storage space for a game room or such.

The T grid was chosen to cover the ugly -- normally plumbing and HVAC runs.

The remaining height is too low for lay-in troffers / can lights.

Instead the solution taken was T-bar wrap fixtures surface mounted. These throw light all around and are cheap, cheap, cheap.

The one time I saw lay-ins the lighting was a terrible gloom of too bright and too dark. Rather like an interrogation setting behind the Iron Curtain.

Tesla,

I just inspected a job with the shallowest lay in fixtures I have ever seen. They couldn't have been more than 2" high. The need was because too much junk above the grid. Pipes, duct work, etc. The EC said that the fixtures were expensive, but they fit the need.

Well, so far you're all on target.

The drop ceiling folks do include specifications for minimum space above the grid - I think it's 5" - in their instructions; but, as has been noted, we're talking about ceilings installed by DIY's and other unprofessional folks.

There is at least one troffer made that is no thicker than the grid - call it 1-1/4".

I was referring to the lenses sold at the home stores fitting in the grid, but your needing to trim them to use them as a replacement lens for a troffer.

The two places I tend to see these are basements - to hide all the ceiling clutter - and kitchens.

The strip fixtures are invariably 'cheap, cheap, cheap.' Cheap even by strip fixture prices. Yes, their install often violates the instructions (some call for a clearance, to not be flat against the ceiling), and have flexible cord connections (a question of 'when' as to that being a code violation).

I didn't want to get bogged down in all those details. It appears that there is no code rule against the basic idea of using strip lights and independent lenses.