It would be much better to use a "no hub clamp". These have a
stainless steel band in addition to the rubber and band clamps.
They are much better about keeping the pipes in line and not
allowing the pipe ends to misalign. These work quite well on cast
iron to PVC connections.

--
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DanG
Keep the whole world singing . . .


"RogerT" wrote in message
...
I am going to be replacing a small section of underground sewer
pipe that runs from the front of my house toward the street. The
existing underground sewer pipe is 4-inch cast iron. I will be
using PVC to replace the line from the front of my house and
connecting to that sewer line about 5 feet out.

Can I use a Fernco coupling to connect the new PVC to the old
underground cast iron sewer pipe?

If not, how is that type of connection usually made?