Phisherman wrote:
I need to add a 2" sink drain to a main vertical 3" drain. I will
need to remove a section of the main 3" drain and replace it with a
PVC fitting to accept the 2" sink drain. Should a Wye or a sanitary
T be used?

Use a WYE or a TEE/WYE.

A san TEE is used where the stack above the TEE
will be used as the vent for the new fixture trap,
which is unlikely the case here.

Jim