In reading the code in regard to expansion joints in pvc conduit it says that in a straight run between securely mounted items you have to compensate for expansion. I have a run approx. 40' along the exterior wall of a building.I will have a 90deg elbow on each end,one will terminate in the meter base the other will LB into the wall and enter the back of the interior load center. Does this install require an expansion fitting. Have always used EMT and never been concerned or needed to know what constitutes the use of an expansion fitting. Thanks.
PVC expansion joints
- Thread starter nizak
- Start date
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- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
The straight run part just means that you cannot count on movement of entire right angle runs at the end to take up the expansion and contraction.
In your case the right angle runs from the elbows will not be able to bend or move enough to make a big difference from a straight coupling to the two boxes.
Tapatalk!
In your case the right angle runs from the elbows will not be able to bend or move enough to make a big difference from a straight coupling to the two boxes.
Tapatalk!
Cow
Senior Member
- Location
- Eastern Oregon
- Occupation
- Electrician
My rule of thumb for my area, is for a 120 degree temp swing 5 feet of conduit will move 1/4". Which makes it's so most any run I do, will require some sort of expansion fitting or a 90 installed in such a way to allow the conduit to expand/contract.
cadpoint
Senior Member
- Location
- Durham, NC
It's when one crosses it, even if it's either in sheer or compression.
If one comes across or is within an expansion joint then IMO
one needs to address it as an expansion, even in a short distance!
I beleive the building code asks for equal or better fill around the pipe to
match material, one can add the expansion on the temperature active side.
If one comes across or is within an expansion joint then IMO
one needs to address it as an expansion, even in a short distance!
I beleive the building code asks for equal or better fill around the pipe to
match material, one can add the expansion on the temperature active side.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
You need to answer some questions here - how much temp change is anticipated and how much change in length of the raceway will that cause? Can the run take that length change without stressing the raceway or a component of the raceway? If not then expansion fittings are necessary to take on that length change. An elbow may allow for some length change, but if the elbow is firmly secured (by either direct strapping or by termination immediately after the bend, it likely can not allow for length changes.
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