This could get interesting if one condo owner wants an upgrade but the main disconnect is shared by the others. Around here for multi
family structures if the condo owner owns their own unit All utilities must be located within their unit.
I am not all that familiar with multi occupancy with multi owner situations, but I would think this would be no different than how other items are handled that are common to more than one occupant, like a driveway, parking lot, landscaping and lawn care, building exterior maintenance, common items related to other utilities, etc.
There could even be a single disconnect for service and meter center, but if any of this needs maintenance, repair, upgrade, cost would likely be shared in some way by all owners. I bet many places have some kind of maintenance dues that go into some fund for such things, and if something special and unexpected comes up then they have to have a meeting and decisions need to be made. Really not much different than a government entity, a general budget and then occasionally something special comes up and how to pay for it needs public meetings and input.
Now if only one owner wants to upgrade say from 100 amp supply to 200 amp supply to their unit only, then they likely end up paying for whatever is necessary to get it done.