The size of your electrical service sets the ceiling on how much power your home can use at once. Many Michigan homes built before the 1980s have 100 amps. Most new homes get 200.
How to tell what you have
Look at the main breaker, usually the largest one at the top of the panel. The number on its handle, 100, 150 or 200, is your service size. A fuse box or a main rated at 60 amps means the service is very old.
What 100 amps can handle
A 100 amp service suits a modest home with gas heat, a gas water heater and a gas range. It becomes tight once you add central air, an electric range or an electric dryer, and it has little to spare for anything else.
When 200 amps makes sense
- You are adding a Level 2 EV charger.
- You are switching to a heat pump, an electric water heater or an induction range.
- You are finishing a basement or building an addition.
- You want a hot tub or a workshop with 240 volt tools.
- The panel is full and breakers have been doubled up.
Alternatives to a full upgrade
If the service has spare capacity but the panel has no free slots, a sub panel may be all you need. For EV charging on a tight service, load management devices can sometimes avoid an upgrade. A load calculation settles the question with numbers.
What the upgrade involves
A 100 amp to 200 amp upgrade replaces the panel, the main breaker, and usually the meter base and service entrance conductors. The utility disconnects and reconnects power, and the work is inspected. Most are done in a day. Details are on our electrical panel upgrade page.