Panels & Breakers

Do I need a bigger panel?

Signs your panel may be undersized

• Breakers trip regularly when running multiple appliances at once, even without an obvious fault
• The panel is a fuse panel, or a very old breaker panel (60A or 100A service in a home that's grown its electrical needs since)
• No room for new breakers — the panel is physically full, or has no space for tandem/twin breakers
• You're planning an EV charger, hot tub, heat pump, or other high-draw addition and the existing service doesn't have headroom
• A home inspection or insurance renewal flagged the panel — some insurers won't cover certain older panel brands or fuse panels at all

What size service does a modern home need?

Most new construction and major renovations in Ontario are built to 200A service today, and that's a reasonable target if you're upgrading anyway — it gives comfortable headroom for things like EV charging and heat pumps without needing another upgrade a few years later. A smaller or older home with modest electrical needs and no major electrification plans can sometimes still get by on 100A, but that margin shrinks fast once you add an EV charger, an electric range, and a heat pump to the mix. The right answer ultimately comes from a proper load calculation, not a rule of thumb — see our Load calculator to get a rough sense of where you stand.

Common Ontario panel sizes, roughly explained

• 60A service — common in homes built before the 1960s; considered undersized for most modern homes
• 100A service — the long-standing standard for many existing homes; can be tight once EVs, heat pumps, or electric ranges are added
• 200A service — the current standard for new construction and most major renovations, with comfortable headroom for electrification
• 400A service — typically reserved for very large homes or homes going fully electric with multiple EVs, heat pumps, and other major loads

Are fuse panels unsafe?

A fuse panel isn't automatically unsafe just for being a fuse panel — fuses do the same basic job as breakers, interrupting an overloaded or faulted circuit. The real issues tend to be indirect: fuse panels are old enough that they're often paired with outdated wiring elsewhere in the home, they're rarely sized for modern electrical loads, and a common and genuinely dangerous practice is "oversizing" — installing a higher-amperage fuse than the circuit's wiring is rated for, which defeats the fuse's protection entirely and lets the wiring overheat before anything trips. Fuse panels are also a frequent insurance flag, with some insurers declining to cover them at all or requiring an upgrade before binding a policy.

Why this is never a DIY project

A panel upgrade means working directly at the point where utility power enters your home — including, in most cases, coordinating a temporary disconnect with your utility company. It requires an ESA permit without exception, and the work must be done by a Licensed Electrical Contractor. This isn't a "call a pro if it gets complicated" situation — it's a "this is a pro's job from the first step" situation.

What the panel upgrade process generally looks like

1. Load calculation. Your electrician calculates your home's actual and future electrical demand to size the new service correctly.
2. Permit application submitted to the ESA before work begins.
3. Utility coordination. Power is disconnected at the meter for the changeover — often for several hours.
4. New panel and service installed to current code, including any required grounding and bonding upgrades.
5. ESA inspection to certify the completed work.

When to get ahead of it

If you're planning any major renovation, an EV purchase, a heat pump conversion, or you're simply not sure how much headroom your panel has left — getting a load calculation done before you commit to other projects avoids discovering the constraint midway through, when it's far more expensive to fix.