A panel upgrade replaces the box, not the supply. That distinction is the whole thing: it is why one quote is materially cheaper than another that sounds similar, and why "upgrade" can mean two different jobs depending on who is saying it.
What actually gets replaced
The enclosure, the buss bars the breakers clip onto, the main breaker, and usually every breaker with it. Each circuit in the house gets disconnected from the old panel and landed in the new one.
The service feeding it — the cable from the street and the meter base outside — stays. If those need replacing too, you are looking at a service upgrade, which is a different scope and a different price.
Why people do it
Space, condition, or capacity, and often all three arriving at once. A panel with no spare slots cannot take another circuit without doubling up, which is where double-taps come from. A panel with a known defect history, or one showing heat damage on the buss, is a safety replacement regardless of how many slots are free.
The third reason is that the panel is fine but the house is about to ask more of it, and replacing it now while the wall is open is cheaper than doing it twice.
What the day looks like
The power comes off. Every circuit gets identified, disconnected, and re-landed, which is the slow part and the part that benefits from an electrician who labels as they go. The new panel is bonded and grounded, the breakers are sized to the circuits rather than to whatever was there before, and it goes back on.
An ESA permit is pulled beforehand and an inspection follows. That inspection is the utility of doing this properly: someone independent confirms the work.
What it does not fix
A new panel does not improve the wiring behind it. Knob-and-tube stays knob-and-tube; ungrounded circuits stay ungrounded. It also does not raise your service size on its own, which is the most common misunderstanding — a 200A panel fed by a 100A service is still a 100A house.
How to spot it in your house
- Count the empty slots in your panel. None left, or breakers doubled up under one lug, means you are already out of room.
- Look for rust, scorching, or a smell of hot plastic near the panel — any of those move this from planning to urgent.
- A panel branded Federal Pacific or Stab-Lok is worth investigating on its own merits.
- Check the main breaker rating against what you plan to add before assuming a panel swap is enough.
The next question
Do I need a panel upgrade for an EV charger?Related terms
- Service upgradeReplacing the panel and the equipment outside it: meter base, and often the mast or the incoming cable. This is what actually raises how much power the house can draw.
- Service sizeThe total amount of electricity your house can draw from the grid at once, measured in amps. Most Ontario homes are 100A or 200A.
- Main breakerThe single large breaker at the top of your panel that cuts power to the whole house. Its rating is your service size.
- ESA permitThe notification a licensed contractor files with the Electrical Safety Authority before doing work that requires inspection. We pull it; you never call ESA.