The number on your main breaker is the most power your home can draw at once. For decades 100 amps was plenty. Then came central air, electric ranges, heat pumps and electric vehicles. So do you need to upgrade?
When 100 amps is still fine
A modest home with gas heat, a gas water heater, a gas range and no EV can run comfortably on a 100 amp service. If your panel is in good condition, has open spaces and you are not planning big electrical additions, there may be no reason to change it.
When 200 amps makes sense
- You are adding a Level 2 EV charger
- You are switching to a heat pump, electric water heater or induction range
- You are installing a hot tub or building an addition
- The panel is full and tandem breakers are doubled up everywhere
- You still have a fuse box or a 60 amp service
The honest way to decide is a load calculation. It adds up your home's actual and planned loads using the method in the electrical code and tells you whether the existing service can carry them.
What a 100 amp to 200 amp upgrade involves
It is more than a new box. A full electrical panel upgrade usually includes a new 200 amp panel and main breaker, a new meter socket, heavier service entrance cable, updated grounding and bonding, a permit, a utility disconnect and reconnect, and an inspection. The power is typically off for four to eight hours.
What affects the cost
Electrical panel upgrade cost varies with whether the service is overhead or underground, how far the meter is from the panel, the condition of existing grounding and whether any wiring in the panel needs correcting. That is why a site visit and a written quote beat any online price guess.
Alternatives to a full upgrade
If the service size is adequate but the panel is simply out of spaces, a sub panel can be enough. For EV charging on a tight service, a load management device can pause the charger when the house is drawing heavily. A good electrician will lay out these options instead of defaulting to the biggest job.
We do panel upgrades across the state, including Milwaukee, Madison and Green Bay.