Old Work Box for Vanity Light?

Question

So I went to go change my bathroom vanity light today and discovered that it simply had the wiring coming through a hole in the wall and the previous vanity was literally just screwed into the wall with 2 screws.

Went to the local home improvement store and the employees guided me to some old work boxes that look like this:

So I get it installed, but it had me wondering...is this safe? I mean the vanity light isn't THAT heavy (I weighed it at around 3 lbs). I do not have a stud nearby (that I can see anyways) (nor would it matter because I would need to have access behind it anyways), and I really don't want to be tearing out an entire wall ideally)

Is this ok? I looked at various guides on changing or adding vanity lights and most seem to use these boxes (Which "seem" to be rated for 6 lb's, and only mention NOT to use them for ceilings).

Answer 1

Yes, an old work box is completely safe for what you're using it for. Just make sure the dogs are snug against the drywall.

Answer 2

Make sure the box doesn't show around the fixture. They usually do and makes it unsightly for the homeowner. I made that mistake as an apprentice once and made a huge mess for the drywall guy/boss man/everyone else to fix. More higher-end expensive fixtures have a wire gutter built-in and the splice takes place inside the fixture. Never splice inside a wall cavity. You need to splice in an UL approved box. Then just place a plastic button connector in the back. Drywall anchors should be fine or find a stud to screw it too if its a long fixture. Unless its a piece of lead or iron, then weight shouldn't be a problem.

Answer 3

I've used lots of old-work boxes of various designs and love them. When you have a heavy fixture, you need one that will support the weight (by being secured to studs or joists), but your vanity light is.... well, light.