The age old question is, Do I need to provide independent support for 2X4 lay-ins in suspended ceilings. My answer has been "No" and qualified by saying that the ceiling needs to be adequately supported and the fixture needs to be secured to the ceiling grid. My code reference is 410.16(C). We have some inspectors who maintain that this type of fixture needs to be supported by the building structure. The grey area is the support of the suspended ceiling used to support the fixture (I think). I usually look for at least 2 support wires at the fixture and they should be on the main "T's" not the cross "T's". Works for me.
