use of expansion joints

farmer56

does 2011 nec code book require the use of expansion joints on any pvc conduit run or just pvc in the ground?

Code05

Both.How long is your run?

352.44 Expansion Fittings. Expansion fittings for PVC
conduit shall be provided to compensate for thermal expansion
and contraction where the length change, in accordance
with Table 352.44, is expected to be 6 mm (1⁄4 in.) or greater in
a straight run between securely mounted items such as boxes,
cabinets, elbows, or other conduit terminations.

bobelectric

Code has tables for types of conduit and expansion at different temperatures.

farmer56

about 40 feet. looks like i have to slip them in there. thanks for clarifying that. wont to that again!

farmer56

put expansion joint in my first run , from transformer to service disconnect. from the service disconnect to distribution panel i did not.since my disconnect and distribution panel were both sittin on the same slab of concrete i didnt. years ago i am sure that would of been kosher but i should of checked this out. will be fun to wrestle that 4/ 0 again. i need to invest in new code book. thanks for your reply and help.

rongiambrone

i ran 22' of 1" pvc conduit. what determines weather i need an expansion coupling or not? does the NEC have a formula to determine this??