Are you securing the fixtures to this 4" box and relying on the box to hold the weight of the fixture?
That's what I was thinking (take another sip of coffee). Probably wrong headed thinking though. I just received this info this morning (that's my excuse).
Weight? Good question...
Ah, here we go...hmmmm....one type of fixture weighs 24lbs. Wow. The other one is smaller but doesn't list a weight.
Under Mounting the cutsheet info says this:
Max. weight: 24lbs.
Installation: Mounts over a standard 4"
octagonal electrical box with 3 1/2" c/c
mounting holes. (by others)
Additional seperate mounting holes are provided with wall plate.
Ok, so separate anchors for the light.