Concrete encased underground

[JDB3]

:?:? At an auto repair shop where I go, they were told that their 650 amp 3 phase service underground service was required to be encased in concrete because of the danger of explosion & the concrete encasementcontaining it.
Concrete was put in the ditch, then 3" rigid metal conduit, & concrete on top. The risers on the pole & to the disconecting means are PVC.
DOES the NEC require this? Is is your standard repair shop.
Thanks,

 

[Sierrasparky]

Sounds like a POCO requirement, This is not a nec issue. Most POCO's I deal with require the bends to be in concrete so that when they pull the wires they do not burn through the conduit into open dirt. I have never heard of this because of explsosion.

 

[kwired]

Sounds like a POCO requirement, This is not a nec issue. Most POCO's I deal with require the bends to be in concrete so that when they pull the wires they do not burn through the conduit into open dirt. I have never heard of this because of explsosion.

After they burn through the conduit then the concrete can just grind on the conductor insulation as it is pulled - good idea there:happyno:

If it is because of potential explosion why is the risers out of the ground allowed to be PVC as well as not concrete encased?