ECN Forum Forums Code Related Discussion NEC & other Code issues Cover mounted fixtures

I have to repair a gable mounted HPS fixture that was mounted on the cover of the WP box and therefore only supported by the 2 #6-32 screws. I think it should be mounted on the threaded hubs, and I remember one of Joe T's photos showing fixtures mounted similarly. However, I come up short when I search for the applicable code article. Am I imagining it?

I've recently had to re-fit several new lights to older construction; I know just the situation you describe. It's especially vexing when the wall is masonry, with a "handy box" set in it- there's not much to work with, and you really don't want to tear up the wall!
Anyway, I'd really like some code guidance as well as "tips & tricks" from you guys!

John W, I'd sure use the hub if possible. Not only do the 6/32s not hold well, most w/p boxes will bust out easily at the point where the box meets the strap with all the 6/32 holes in it.
John S, A couple of things I've tried:
Retap holes to 10-32 (not much help)
In masonry, remove back K/O from box, drill hole completely through wall, & use a piece of threaded rod with nuts & washers.
(Does anybody still make the fixture studs that screw to the back of the box?)

With highbays:
Swivel covers (by Appleton) with conduit stems.
If hanging from a K/O in a welded box, be sure to use the formed, and not welded, side of the box for support. I've seen the entire welded portion of a 4S box give way with a 20lb fixture attached. If not for the safety chain it would have fallen 35 ft and made a very uncomfortable hat for someone.

Thanks for the input. As I said, I think I remember reading this in the code. I can't seem to find it though.

Redsy;
370-27(a)EX ???

Sparky,
That must be it. Thanks!
I guess that means a wall sconce or entrance light weighing less than 6 lbs. may be mounted on a single gang device box. Could it actually be argued that a 3 hub WP coverplate on a single gang WP box is "designed for the purpose"? It still relies on the 2 #6 screws. A round box with the #8s is a safer bet, but I'll use the hubs on the box to be sure.

Sparky,
I finished today, and replaced the old box and fixture. I used the hub instead and although "the other one was fine for 15 years", I'm glad I change it.
BTW,
I had to use a threaded Killark street 90 to get the back of the fixture to clear the wall.

Good man Redsy.
i take it whole arguement is screw size vs. fixture wieght. I was crusin' the NEC for that recent change ( 99'??) that allows us to use cieling mounted boxes for the same rationale, no soap as yet...