I hear my name being called
Here's the typicals in So. California - along with specifics for LA County [where La Mirada is]:
- Troffers in T-Bar ceilings: Typically use 2 ceiling wires for support [independent from wires going to the grid] - connect to opposite corners. Screw fixtures to/through grid at opposing corners from the wires [if wire on left, screw on the right].
Some LA County Inspectors [Building and / or Electrical] may require 4 wires and / or 4 screws. Last time I worked in La Mirada, we only needed to do 2 wires, 2 screws. - Other fixtures mounted to T-Bar Ceilings [Recessed Cans, Exit signs, etc.]:
These will require box support, so the fixture and outlet box does not rely solely on the ceiling tile. They will also need 2 wires, which can be connected to the support mounting means, unless the fixture has provisions for them.
Exit signs and other emergency egress lighting [other than troffers] may need to have the entire tile secured in place - possibly the surrounding tiles too! [had to do this in Manchester district and Westwood Village]. - Hard Ceilings: Unless noted otherwise on your planset, these generally do not require ceiling wire supports.
- Conduits and Raceways run above T-Bar ceilings:
For any conduits run in the ceiling space [whips between fixtures, etc.], they shall not be secured to the wires supporting the T-Bar grid [main runners, seismic braces, etc.]. You will need to get some ceiling wires, then hang them yourself for your conduit runs [fixture whips close to the termination at the fixture may be able to use the independent fixture hanger wire, which you land a Caddy-Clip to].
Terminate the loose ends of independent wires to the ceiling grid.
These items should do you fine, but if you aren't sure - check with the AHJ [City of La Mirada Building Department]. Ask them what they prefer.
Most California AHJs will apply the CBC [and in conjunction the CEC] to T-Bar Ceiling installations. These items I have listed are not in the NEC.
Before doing anything in the ceiling space, get a complete, full sized [D or E sized pages] and MOST CURRENT REVISION PLANSET!!! [not yelling, just a major headache area for me with the 7,000 rev. sets floating around a project!].
Look in the "A" sheets [Architectural] for the Reflected Ceiling Plan. There should be grid and suspension wire details on this page. If not, there should be some type of notation of what page it's on. Look for either a "Detail" callout line [circle with detail number above page number], or look in the title block. It would either be the page ahead of, or immediately following the RCP.
Lastly, look at the first page on the set - the one where the scope of work is noted. Verify the applical codes to this project. Also, if the TOC [Table Of Contents] is on that page, you might find the ceiling specs easier.
Good Luck!
Scott SET