Thanks for the info gentlemen.
Not a common thing around here. Our POCOs do UG distribution (BUD) up to the line side of the meter pans.
When a HO or builder wants 'underground' for a new SFD in an overhead zone, it is the customers responsibility to supply & install conduit & conductors from a designated pole to the meter pan. The POCO has requirements for the conduit larger than the NEC requirements.
Reduced neutrals on the service side are not allowed by the POCO, for customer installed services.
