Junction box covers with KO as a means of device support?

[two-bit]

Can you use a junction box cover with a knockout as a mounting mechanism for a water heater timer?

I am looking at the installation guide for a water heater timer that that instructs installers to mount a 4 square box (opening up) to the top of the water heater, then mount the timer to a box cover with knockout by the nipple on the bottom of the timer. The nipple is the only means of support for the device which sits atop the box.

While I can't find any code reference that specifically calls this out, it's a flimsy installation and seems kind of shoddy.

Anyone seen this before or know how it's justified (or not)?

Thanks!

 

[tom baker]

Do install instructions have a picture you can post?

 

[retirede]

Sounds similar to how some doorbell transformers are mounted. I don’t see an issue, especially since it’s part of the manufacturer’s instructions.

 

[two-bit]

I can't share the picture because it's copyrighted material. But the knock out in the box cover is the only support and the device is much larger than the 4 square box.

 

[two-bit]

Doorbell transformers, I've always attached them to a KO in the side of the handy box, not the removable cover.