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Re: Light Fixtures -- Seismic

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Oops. sorry for the blank response.  

The intent of the wire ties for suspended ceiling and the drop in light
fixtures is to keep the ceiling grid up from falling down during the EQ.
 Thus,  the four directional diagonal tie wires periodically to add some
lateral rigidity to the veritical support wires.

Thus,  it is my understanding in the case of a light fixture suspended alone,
 the sway braces generally are not required,  even on essential services,  so
long as the conduit box is adequately braced to carry the load;  so long as
the wire supports for the fixture are adequately rated for the load;  and so
long as the swing arc of the suspended lamp doesn't hit something.   Only in
the last case would some sort of sway bracing be required.

Ron Fong
Fremont,  CA.,  
who did feel dat 3.2 EQ on the Hayward fault yesterday and wonders if it
actually relieves the stress;  or is a precursor to the big one!