Do you typically use 3-0 or 4-0 round boxes at resi rough-in?

[JoeNorm]

Title asked the question. An old timer I worked for always used 3-0 because he said he's been burned by too many light fixtures not being big enough to properly cover the hole. Recently I have been having the opposite issue, where the specific light is only sized for 4-0 and has to be adapted to fit 3-0.
Not to mention they only seem to make cookie cutter style box extenders for 4-0.

Any wisdom here to share?

 

[electrofelon]

Very very rarely do I find I should have used a 3/0. The one exception is those track floating canopies which are just slightly over four inch and frequently don't cover a 4/0

 

[LarryFine]

In new work, I like 3" nail-ons for smoke detectors.

 

[CoolWill]

In new work, I like 3" nail-ons for smoke detectors.

I just use single gang nail-ons for smoke. It's cheap. But I have never used a 3" round box. Never. I just don't see the use.

 

[electrofelon]

I just use single gang nail-ons for smoke. It's cheap. But I have never used a 3" round box. Never. I just don't see the use.

They are actually 3.5"

 

[CoolWill]

They are actually 3.5"

Oh, well, nevermind then. I'm going out to buy a case now

 

[readydave8]

We used to see sconces that wouldn't cover 4" box

 

[JoeNorm]

Sounds like no general consensus

 

[Fred B]

They are actually 3.5"

came across some really old 3" round. not really useful anymore with the box fill limits of the newer codes.

Mostly will use the 4" but have as others stated had the sconce not cover. Usually best to have the light sizes planned before installing the boxes, or have control of the lighting fixture choice.

 

[James L]

I went through a time where every light fixture (sconce) I installed just wasn't quite big enough to cover the muffed up part of the drywall around a 4-in box

Well I found a whole case of 3.5-in boxes on eBay and decided to go that way because it just made sense. So I roughed in probably eight bathrooms using those smaller boxes.

Then came time for the finishes and none of the screw holes lined up

Can't win for losing

The only surefire way is to have the light fixtures on the rough-in

 

[Dennis Alwon]

Occasionally, we get specs ahead of time and found that, in some cases, a rectangular switch box was needed and other times a 3" round. The 3" round and the sw boxes were most for European fixtures.

 

[JoeNorm]

Funny, after I wrote this I had an Italian fixture to install over a 4" round box.......didn't cover it!!

The whole "need specs of lighting beforehand" is a good idea in theory but not all that practical with the way work often happens

 

[James L]

A lot of times, there are no specs. There may be pictures, but half the time no pic of the base. No measurements of the base, nothing.

Having the fixtures is the only way sometimes.

Then you're at their mercy to stay with the plan

 

[electrofelon]

Funny, after I wrote this I had an Italian fixture to install over a 4" round box.......didn't cover it!!

LOL, just today the lighting designer on a job I was on told me to make sure to use the smaller boxes for these sconces they are getting.

 

[Fred B]

Can't say with 100% certainty but a lot of the odd sized fixtures I come across also seem to be missing a NRTL listing for here in the states.

Another option while roughing in is use of a 4x4 and mud ring. Can get rounds in multiple sizes.

 

[AC\DC]

What ever I ordered