A: This is not a waterproof cable like an outdoor extension cable. It can only be used on Pressurized water lines in Iron, copper, pvc or Pex lines in dry spaces.
A: This will work on 2" PVC pipe as long as this is a pressurized water line. It will not work on drainage lines.
A: It will not operate on a drain line. The thermostat will not read the temperature of the drain pipe since it is not a pressurized line.
A: Yes you can use zip ties. Be careful not to cut onto the jacket around the central wire.