A service upgrade replaces everything from the utility's connection point to the panel, and it involves parties beyond the electrician.
What gets replaced
Service entrance conductors — the cables from the utility connection to the meter and from the meter to the panel — in the larger size the new rating requires.
The meter base, which is rated for a specific service size.
The mast, weatherhead and riser on an overhead service, or the conduit and conductors on an underground one.
The main panel, with a main breaker at the new rating.
The grounding electrode system, brought up to current requirements — typically ground rods, the water pipe bond, and a bond to the metal gas piping and to the building steel where present.
The branch circuits reconnected, with AFCI and GFCI protection as currently required. This last item is frequently the largest single line and it surprises people.
Who does what
The electrician does everything on the customer side.
The utility disconnects the service, and reconnects it after the inspection. On an overhead service they may also replace the drop; on an underground one the responsibility split varies by utility.
The authority having jurisdiction issues the permit and performs the inspection between the two utility visits.
That sequence — disconnect, work, inspect, reconnect — is why the job is not a single-day appointment even when the labour is.
The schedule
The utility's disconnect and reconnect appointments are the constraint. Depending on the utility and the season, the gap can be days.
Where the work cannot be completed between two visits on the same day, the household is without power in between. Ask specifically how the contractor plans to sequence it, because "one day" and "one day of work" are different statements.
What frequently comes with it
Relocating the panel, if the existing one is in a prohibited location — a clothes closet or a bathroom — or has inadequate working clearance.
Moving the meter, where the utility requires a different location or height than the existing one.
Repairing the wall where the old service entered.
Correcting existing violations found once the panel is open, which are common in an older house and which an inspector will require to be addressed.
Each of these is legitimate and each of them should appear on the quote rather than as a change order.
Overhead and underground
Overhead is cheaper and faster. The mast and weatherhead are on the outside of the house and the drop comes from a pole.
Converting to underground is a much larger job — trenching, conduit, possibly a utility charge — and it is usually done for appearance or where a drop is in the way of something. It is not required by a capacity upgrade.
The permit
Required essentially everywhere, and the inspection is the point of it: an independent check between the work and the reconnection.
A contractor who proposes to do the work without a permit is proposing to have the utility reconnect an uninspected service, which most utilities will not do, and which leaves the household with unpermitted work to disclose at sale.
The question to settle first
Whether the upgrade is needed at all. Position count in the panel and calculated load are different problems, and only the second requires this job.
Ask for the load calculation before agreeing to any of the above.
Doing other work at the same time
The power is off and the panel is open, which is the cheapest moment for anything else electrical.
Common additions: a subpanel for a garage or a basement, a circuit for a future EV charger, a generator interlock or transfer switch, whole-house surge protection at the panel, and correcting any aluminium branch circuit terminations.
Each is a fraction of its standalone cost when the crew is already there and the service is already down.