fixture crossbar

[-marty]

I have never been able to figure the purpose fro thr crossbar except where the mounting holes do'nt line up.

I use them because the manufacturers instructions require it.

So, on the current job I read the instructions for the crossbar "attach the crossbar with the screws on the box".

Since plastic boxes don't come with screws can I assume I don't need a crossbar for plastic boxes?

thanks

 

[mthead]

fixture crossbar

A plastic box listed for use as means of mounting fixtures, will come with the appropriate mounting hardware.

 

[hillbilly]

I always use them. The reason is to keep some of the heat away from the screw holes in the plastic box. In the past, I've seen some of the enclosed, surface mounted light fixtures actually come loose from the box because of the plastic softening from heat. If you mount directly to the box, the screw ends are in the light compartment and conduct heat directly into the plastic. With the "fixture crossbar" the heat has to travel further and thru more metal so the plastic stays cooler. This is my theory. It may not hold water, but I haven't had any light fixtures falling because of heat.
steve

 

[allenwayne]

A plastic box listed for use as means of mounting fixtures, will come with the appropriate mounting hardware.

When was the last time you bought a plastic box that had screws for mounting with it ???? 314.27 exc.allows a 1 gang plastic box to be used to mount a wall fixture under 6 lbs. does it come with screws for this ???IMO the cross bar is there to ground the fixture when used in a plastic box install.