Acceptable meter-socket models and their various distribution modes seem to be an intensely regional practice. The only aspect that offsets this variable a bit is that most large and a growing number of smaller utilities {of which there are no slight number in the US} are publishing their policies/specs at their websites.
{Read on only if you’re really, really bored…} There is one industry-standardization group Out West, but even within “EUSERC” the variety of drawings and specs for sockets above a residential 200-amp form-2S can be vast.
It is worth noting that typically a 'cold turkey' call to a utility meter department will guarantee strict “by trained stuntmen only“ orders that seals, meters and service-drop/-lateral conductors are not to be touched by non-utility personnel, but if you’re one of their established/local “good ol' boy” contractors, the practice is condoned and sometimes expected by them.
OTOH, way back when I remember one utility feigning convulsions while threatening to call the National Guard, Mental Hospital and Governor’s Office for doing the same. [They were also indeed most uncooperative and non-committal about responding to a disconnect and reconnect for a bonehead farmhouse service change. They were, however, good for sometimes leaving behind a very cool “Salisbury Joint Paste Pot,” canvas bucket or an occasional wood-handled Burndy MD-6 press, but if you wanted to get a service knob or a PG connector from them, you had to drive to their corporation yard on the opposite end of the county with a minimum 2-pound can of coffee as barter.]
[This message has been edited by Bjarney (edited 09-04-2003).]