wwhitney
In the Trades
No, the diameter of the 3" nominal pipe is 3.5", and so the PVC coupling should have an OD of about 4". Hence the difficulty of putting it in a 2x4 wall.- The studs are 3.5" deep (2x4s).
- The shielded coupling is about 1/2" thick. The pipe and coupling together is about 4 to 4 1/8" diameter.
- The 3" PVC coupling is about 1/4" thick and per Google, should be about 3.5" in diameter.
Since the shielded coupling is the largest diameter, if you have access and clearance below, it might be possible to move all the shielded coupling(s) down below. That coupling is also the wrong type (it's for use underground), although that version is arguably as beefy as the correct type. The correct above ground type (Fernco Proflex 3005-33 or Mission Rubber Band Seal P-300) might have a smaller diameter, not sure.
You'll still be left with the difficulty of the 4" OD on the PVC coupling, however.
Cheers, Wayne