Why panel size matters more than you think
“Hey, Jon. What size electrical panel do I need?”
When you’re adding something new to your home, like an EV charger, hot tub, or basement suite, your existing electrical panel might not be able to provide the additional power needed.
Panel size, measured in amps, determines how much power your home can safely distribute at once. It also plays a major role in the overall cost to upgrade an electrical panel, which varies based on size and configuration. If your panel is too small, you risk tripped breakers, failed inspections, or worse, an overloaded system.
The right panel should meet your current needs and give you space to grow. What works today might not be enough in a few years, especially with EV chargers, finished basements, or energy upgrades on your to-do list. If you’re wondering ‘What size electrical panel do I need?’, the answer depends on your home’s current and future power demands. See what a certified panel upgrade involves.
100 amp vs 200 amp panel: What size electrical panel do I need for my home?
Here in Ontario, most modern homes have a 100-amp or 200-amp service, but bigger homes or those planning for future additions might need even more.
- 100A: Supports smaller homes with standard appliances, but can become limiting as you add more load.
- 200A: Considered the current standard for new builds or renos. Offers room to grow and safely power high-demand systems.
- 400A: Rare, but may be needed for large homes with EVs, dual HVAC systems, or secondary suites.
If you’re unsure of the size electrical panel you need, an assessment is the safest first step.
How many amps does my house need? Key factors to consider
Panel sizing isn’t one-size-fits-all. A proper load calculation considers:
- The number of high-demand appliances (dryers, ovens, heat pumps)
- EV charger plans
- Basement finishes, hot tubs, or future add-ons
- Solar setups or backyard suites
A qualified electrician can run a load calculation that meets Ontario Electrical Safety Code standards. It’s not random, it’s math, backed by compliance. For a homeowner-friendly breakdown of how load management works, BC Housing offers a practical guide to understanding electrical load and safety considerations.
Mistakes to avoid when assessing panel needs
It’s common to assume everything’s fine if the lights aren’t flickering. But that doesn’t mean your panel isn’t maxed out.
Common mistakes include:
- Upgrading appliances without checking panel limits
- Assuming a subpanel adds capacity (it doesn’t)
- Trusting online calculators over a professional load check
- Skipping ESA inspections or using non-licensed installers
If you’ve asked yourself, “What size electrical panel do I need?” make sure you’re working with someone certified to answer that properly. These shortcuts can lead to insurance issues or safety risks down the line.
Regional considerations: Hamilton-area realities
Older homes in Hamilton often still run on 60-amp or 100-amp fuse panels. This can become a bottleneck during resale, renovations, or insurance renewals. We handle ESA-certified upgrades in homes just like yours. See our Hamilton electrician services for more.
Local permits require ESA-compliant upgrades, especially if you’re:
- Selling your home
- Upgrading wiring
- Adding new high-load systems
A properly sized, code-tight panel can support your needs today and help protect your home’s future value.
Real scenarios where the panel size becomes critical
A growing family adds an EV charger and a heat pump
A 100A panel might have been fine five years ago, but now you’re charging a vehicle, running energy-efficient HVAC, and powering a busy household. Suddenly, your capacity is maxed out.
A basement rental adds demand you didn’t plan for
Finishing a basement or adding a rental suite means more lighting, heating, outlets, and possibly kitchen appliances. All of which add up quickly.
A renovation reveals outdated equipment
Many older fuse panels aren’t just undersized, but they’re also out of code. Replacing them is smart and often required during upgrades.
What to do if you’re unsure about your panel
If you’re not confident about your panel size, or even what you have, you’re not alone. Most homeowners only think about their panel when something goes wrong.
At ElectricSafe, we offer straightforward assessments, clearly explain your options, and don’t pressure you to upgrade unless it’s necessary. John still answers the phone, and he’ll walk you through the process to determine exactly what size electrical panel you need for your home.
Before you book: 3 things to check on your existing panel
- Main breaker amperage: Usually marked at the top of the panel
- Spare circuits: If every slot is full, expansion could be limited
- Panel brand and condition: Older brands like Federal Pioneer may have recall concerns or be difficult to service
These aren’t guaranteed reasons for an upgrade, but they are good clues. Knowing what you’re working with helps you ask the right questions.
Common triggers that mean you might need a bigger panel
- Planning to install an EV charger or hot tub
- Adding a basement suite or finishing your basement
- Regularly using extension cords or power strips to add outlets
- Your insurance provider flagged outdated equipment
What size panel do I really need? Answers to common questions
Can I add a subpanel instead?
Only if your main panel has room to support it. A subpanel adds circuit space, not overall capacity. You can read more about how an electrical sub-panel works and when it makes sense to install one.
How do I know if I’m overloading my panel?
Frequent breaker trips or dimming lights under load are warning signs. But the most reliable way to know is with a professional load calculation.
Is 400 amps too much for a regular house?
In most cases, yes. But large custom homes or those with major electrical loads might require it. We’ll help determine if it’s necessary and make sure it’s code-compliant if it is.
Do I need a permit to upgrade my panel?
Yes. In Ontario, any panel upgrade requires a permit and an ESA inspection. A certified electrician will handle this as part of the process.
What’s the difference between a fuse panel and a breaker panel?
Fuse panels use replaceable fuses that must be changed after they blow. Breaker panels use switches that can be reset. Breaker panels are safer, easier to manage, and required for most modern applications.
