Sparkyinak is technically correct according to NEC 352.44. There is not enough thermal expansion in the 7' of PVC riser to need an expansion fitting.
However, frost heave can cause damage to PVC. As the ground freezes in areas of cold winters, the ground actually slowly rises. This can put quite a bit of pressure on a PVC riser if it is entering a CT cabinet or other fixed cabinet. PVC also gets very brittle when cold and also as it ages. So over time, pvc conduits in cold areas can be damaged by the frost.
I have been asked to install expansion fittings by inspectors in cold areas, and some inspectors interpret 352.44 to include frost heave movement, even though it is not specifically mentioned. This subject certainly can be debated either way, depending on your point of view.
Re: PVC underground installation
#186342 05/06/0910:06 AM05/06/0910:06 AM
Although the NEC does not spell it out, the NEC handbooks states that expansion fittings are not typically used in underground work. typically pipes are buried below the frost line to prevent upheaval (spelling). Below the frot line the temp is pretty much constant. I also do believe if you read the expansion fittings lititerture, it also talks about not needed in underground work