Transition to metal conduit above ground in subpanel?

[hitehm]

We typically see underground pvc raceways transition to a metal raceway when they emerge from grade either immediately above ground or halfway up with just a short section of metal conduit entering the bottom of the metal subpanel. But is this necessary? The enclosure will rest on the conduit but the conduit itself will not be fully supporting the enclosure. This is inside the wall btw so not exposed to physical damage and you need to run an EGC with the conductors that will bond to the metal enclosures on both ends. So why make the transition and where is this addressed in the NEC?

 

[infinity]

No idea why someone would do that if physical damage protection was not required. Can you post some photos?

 

[hbiss]

Doesn't Vegas have a prohibition against PVC?

-Hal

 

[hitehm]

Doesn't Vegas have a prohibition against PVC?

-Hal

For the service riser yes, it must be rigid but not that I know of for subpanels

 

[retirede]

No idea why someone would do that if physical damage protection was not required.

Cheaper than an expansion fitting??? Just spitballing.

 

[busman]

No idea why someone would do that if physical damage protection was not required. Can you post some photos?

I transitioned from PVC to rigid at the elbow below ground where my garage feeder enters my house (2") both for protection from the lawnmower jockeys and also for avoiding damage to the elbow when pulling (although just force of habit as it was an easy 70' pull and would not have hurt a PVC bend).

 

[Strathead]

We typically see underground pvc raceways transition to a metal raceway when they emerge from grade either immediately above ground or halfway up with just a short section of metal conduit entering the bottom of the metal subpanel. But is this necessary? The enclosure will rest on the conduit but the conduit itself will not be fully supporting the enclosure. This is inside the wall btw so not exposed to physical damage and you need to run an EGC with the conductors that will bond to the metal enclosures on both ends. So why make the transition and where is this addressed in the NEC?

This is usually a specification that requires this. However, in assembly occupancies, PVC above grade in a wall must be protected by 2" of concrete. This means that even in a block wall the cell needs to be poured.