Easier to install than drywall, a suspended ceiling allows simple access to overhead mechanical systems. It's comprised of a grid that supports 2 x 4- or 2 x 2-ft. panels.

Outlet boxes [314.23(D)] and luminaires can be secured to the suspended-ceiling grid if securely fastened to the ceiling framing members by mechanical means, such as bolts, screws, or rivets — or by ...

Outlet boxes [314.23(D)] and luminaires may be attached to a suspended-ceiling grid that's securely fastened to ceiling-framing members [410.36(B)]. Most suspended ceiling systems aren't part of a ...