I would like to remove a 4 gang steel box that is pretty shallow. I would replace it with an old work PVC box that is deeper. I would like to add 2 smart switches replacing existing switches on left and right side of the box. I think there are too many wires in there to add the smart switches in that shallow box.
<img src="https://cimg1.ibsrv.net/gimg/www.doityourselft.com-vbulletin/1857x1393/20201117_145913_962e920fffc2a833c0a7c9e92382e5bb21b26b62.jpg" width="1857" height="1393"/>
<img src="https://cimg3.ibsrv.net/gimg/www.doityourselft.com-vbulletin/1769x1327/20201117_145816_99376e07d35d4a6d4bee4f656627e38d9994ab51.jpg" width="996" height="1327"/>
<img src="https://cimg9.ibsrv.net/gimg/www.doityourselft.com-vbulletin/1729x1297/20201117_142151_32e34ebec0dda6e609a918acd784672d2c5a3e18.jpg" width="1729" height="1297"/>

My question is how much work will it be to get the existing box out? I see the metal bracket on the left side of the box which apparently connects to the face of the stud on that side. There is a large screw in the middle of the right hand bay which I don't know what it does. Looks like it might be clamping something to the back of the box.

The studs are 2X4's and it appears that nothing is behind the steel box. So I'd like to replace with a PVC 4 gang old work box that is a good inch deeper. The house was built in early '80s and I believe the steel box is original.

 

Hi, I would double check that wall thickness, use an oscillating tool with a metal cutting blade and cut the brackets off.
Make sure you label everything and take pics before you take anything apart.
Geo🇺🇸

 

Thanks Geo. I am sure about the depth of the stud bay and I have tools that will cut the steel bracket off. Do you have any idea what that large screw on the right side of the box (last pic) is for? It concerns me because I don't know what it does.

 

It may just be a blank to fill the hole OR it's the bar from a bar box used as some type of rear support.
You should be able to take the screw out to remove the box and take care of the bar later if that's what is in there.

<img src="https://cimg5.ibsrv.net/gimg/www.doityourselft.com-vbulletin/590x175/barb_3b375b5cf267b2ac31f3edc0c54d579693d4fbbd.jpg" width="590" height="175"/>

On edit: I can see the bar in the back of your box. It's on an angle from 2pm to 8 pm.

 

Hi, I would try loosening that screw a bit and see what happens, really not going to matter anyway, if you want to change the box to Plastic what ever is there will need to come out anyway.
Geo🇺🇸

 

It is a bar clamp just as Pete said, and the bar is right where he said it was too. Good eye!

I was really wondering why a box that long was rock solid on the right side.