Very true on their MV side, however almost all 'service manuals' I have seen include instructions similar to this from Xcel Energies, in regards to metering compartments (not meter sockets.)How do we know which is the b phase? Utilities use any phase as the high leg.
http://www.xcelenergy.com/staticfiles/xe/Corporate/Corporate PDFs/Xcel-Energy-Standard-For-Installation-and-Use.pdf2. ?B? phase shall be that phase having the higher voltage to ground on
3-phase, 4-wire, delta-connected systems.