Is there something in the building code about guage and number of wires to support troffers? All I can find in the NEC is 410.16(C). You can't get by with just the earthquake clips can you? Haven't been able to get in contact with AHJ.

#10 jack chain works wonders.

Check the Plan Set's "A" Sheets (Architectural) for the Suspended Ceiling details page(s). This may start your journey to the Holy Grail O' Compliancy.
The "RCP" (Reflected Ceiling Plan) may contain the information, or at least have some Call-Outs / Referenced Detail #s / Page Notes to direct you to the information.

If the EE Firm that designed the Power and Lighting Systems has included a Details Page, you may find information there too.

In all cases - unless you are familiar with the Local Building Codes (and in conjunction, the Local Electrical Code), the best bet is to ask the Building Department what is required for Fixture Support and Securing in Suspended Ceiling Systems - T-Bar Ceilings to be precise.
They will most likely have two answers:
One that applies to Fixtures weighing 50 Pounds or less;
And one that applies to Fixtures in excess of 50 Pounds.

FYI, in California (at least most of the State ...), the "Basics" are:

<OL TYPE=A>

[*] For Fixtures of 50 Pounds and less: Two #12 Steel wires minimum, landed to opposite corners; Fixture also screwed to the Grid at opposing ends from the wires... at the sides where the wires didn't land,


[*] For Fixtures exceeding 50 Pounds: four #12 Steel wires - one at each corner, with screws at each corner.
</OL>

Along with these things, all Raceways and Cables above the Ceiling must be supported on Independent Wires - not the wires used to support the Ceiling, or perform Seismic Bracing of the Ceiling.

So this means all Electrical Equipment will have wires of their own.

Who installs them is a different thing!

Scott35

Another California-ism.Maybe elsewhere too)

The screws, rivets (whatever you use) must be attached to ceiling grid main runners - - not to the cross tees.

Like Scott says, you should check with your AHJ. At least in this area, the answer can vary widely.

I once had a detail on a set of plans drawn not-in-earthquake-land that showed 12 wires to each fixture. Guess the guy figured better safe than sorry...We had to send it back to the engineer to get a more "reasonable" approach
...S