Rigid Steel Conduit Elbows UG

[publicgood]

Rigid steel conduit elbows. Do you find this as a spec requirement often? Reasons for or against? Direct buried conduit versus concrete encased duct bank make a difference? Alternative measures to address the main concerns? Good value engineering suggestion to change to PVC?

 

[LarryFine]

Presuming just the elbows, for pulling conductors without damage that might happen with PVC elbows.

 

[Dale001289]

Rigid steel conduit elbows. Do you find this as a spec requirement often? Reasons for or against? Direct buried conduit versus concrete encased duct bank make a difference? Alternative measures to address the main concerns? Good value engineering suggestion to change to PVC?

Yes, it is almost a universal specification in the oil and gas industry. It definitely helps for pulling at the 90 degree stub-up and horizontal bends. The concrete stabilizes and protects the conduit.

 

[roger]

Reasons for or against?

Prevents burn through on longer runs, on short runs not really a concern.

Roger

 

[Dale001289]

Presuming just the elbows, for pulling conductors without damage that might happen with PVC elbows.

I've seen PVC elbows break during concrete pour at stub-ups, particularly smaller diameter under 2". Its also a bit more logical to transition (PVC to rigid steel) below grade rather than above - that is if you're going vertically into a piperack, cable tray or building after you stub-up.

 

[augie47]

Beginning to fiberglass being used in place of galv. elbows. One advantage is eliminating bonding issues on above slab stub ups.
http://www.unitedfiberglass.com/images/stories/pdf/elbowflyer.pdf