XHHW underground

[Juanvaldez]

is this an accaptable installation? 4" sch 40 PVC, 3-750 al XHHW run in conduit to a transformer (45'). Conduits terminate at edge utility co transformer. Conduits do not 90 up into transformer, but stop at edge. Is XHHW permitted to be ran this last 24" into transfrormer, W/O continous run of PVC?

 

[augie47]

are they buried in the dirt or is there a cavity under the pad ?

 

[Dennis Alwon]

are they buried in the dirt or is there a cavity under the pad ?

Sounds like they didn't stub up from 24" down and came straight up with the conductors. Is it USE cable? If it is just xhhw I think it needs to be in conduit.

 

[augie47]

What if it is in a open cavity under the slab in free air and not buried under/in dirt ?

 

[Bullcub145]

Do the 4" PVC conduits run into a box out under the pad? If so then I would say you are ok, otherwise you should have the conduits turned up into and above the pad.

 

[Dennis Alwon]

What if it is in a open cavity under the slab in free air and not buried under/in dirt ?

:grin: I like your definition of free air...:grin:

 

[mphillipps]

Can THHN be used in underground PVC. I've seen conduit run and eventually water gets in and covers the wire.

 

[Dennis Alwon]

Can THHN be used in underground PVC. I've seen conduit run and eventually water gets in and covers the wire.

No but most THHN is dual rated THHN/THWN

 

[augie47]

Can THHN be used in underground PVC. I've seen conduit run and eventually water gets in and covers the wire.

No, but, most THHN also carries a THWN designation.
"W" takes care of wet.