Looking at buying a new house? Or possibly you already own one. If it’s an older home from the first half of the 1900’s look at the electric meter base. That’s the metal part that the glass attaches to, if it’s anything other than round you are good!
If it’s round it’s only rated for 60 Amps of electricity. 100 Amps is the minimum requirement for any home, the older service must be upgraded immediately. Upgrading may be as simple as changing out the meter hub, but that’s rare. Generally new wiring is needed from the top of the mast all the way into the electric panel inside the house.
Quite often the panel will have already been upgraded to breakers (and 100 amp capacity) and will be fine. If not then it must be replaced and the grounding and bonding wires replaced. The power line from the street to the mast or connection to the house is generally the utility companies responsibility and they will upgrade it at no charge to the homeowner.