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If you’re considering a solar panel installation in Calgary, Edmonton, or anywhere in Alberta, your installer might mention the need for a Main Panel Upgrade for Solar — also known as a main panel swap. But what does that actually mean, and why is it sometimes required for larger solar arrays? At Solar YYC, one of the most common questions we hear is:“Why do I need to change my electrical panel just to add solar?” The answer comes down to something called bus bar capacity — a technical but important factor in safely installing your solar energy system. What Is a Main Electrical Panel? Your main panel (also called the electrical service panel or breaker box) is the central hub where power enters your home from the grid. It distributes electricity to your lights, appliances, and outlets through individual breakers. Panels have two important ratings:– Service rating (e.g., 100A, 125A, 200A). Service rating is the capacity of the wire coming to your home from the local grid. This is generally difficult, and expensive, to upgrade.– Bus bar capacity — the metal strips inside the panel that carry electrical current When you install solar, you’re adding another source of electricity to this panel — and the panel must be rated to safely handle both the grid input and the solar input. What’s a Bus Bar and Why Does It Matter? The Canadian Electrical Code (CEC) Rule 64-112 outlines how renewable energy systems, such as solar, integrate into both new and existing electrical panels. The panel bus bar must be able to handle the combined current of the main breaker amperage (incoming from the grid) and the solar back-feed breaker amperage (incoming from solar system). Definition time! Safety Margin is the amount of additional capacity or strength built into a system beyond its expected or design load to ensure safe and reliable operation under unforeseen conditions or overloads For residential systems we are allowed to add a 25% safety margin for example: A main panel with 100A main breaker and a 125A bus bar would allow us to install 56.25A worth of solar PV breakers.  125A bus x 125% = 156.25A – 100A main breaker = 56.25A.  In 2025, and considering Solar YYC’s current offerings, this would equate to between 11.7kW and 13kW DC of solar. Or, 26 panels. For commercial systems we are only allowed a 20% safety margin: A main panel with 200A main breaker and a 200A bus bar would allow us to install up to 40A worth of solar breakers. 200A bus bar x 120% = 240A – 200A main breaker = 40A If the bus bar above is upgraded to 225A: 225A bus bar x 120% = 270A – 200A main breaker =70A Why Main Panel Upgrades for Solar Are Often Needed In Alberta, most homes were built with 100A panels with 125A bus bars, which worked fine when solar wasn’t common. But solar is becoming more powerful and cost-effective — and homeowners are aiming for full offset or near net-zero energy usage. IMPORTANT NOTE When solar companies talk about upgrading your panel it’s almost never the service size but rather just the busbar. A typical upgrade looks like this: 125A bus x 125% = 156.25A – 100A main breaker = 56.25A of room for solar. Or, 26 panels.  Upgrading the busbar to 225A: 225A bus x 125% = 281.25A – 100A main breaker = 181.25A of room for solar. Or, 50 panels.  By upgrading the bus we have doubled the capacity for solar. Do I Always Need a Main Panel Upgrade for Solar? Not necessarily. If your energy needs are modest, and your existing panel has space and bus bar room, we can often install solar without changes. But if you’re planning a larger system, a panel swap is usually the only option. At Solar YYC, we assess this for every project usually with a thorough site visit (free of charge!). Then we include upgrade recommendations in our quotes — with clear pricing. We also handle all permitting and coordination with the city and utility, whether you’re in Calgary, Edmonton, or elsewhere in Alberta. What does it cost and how long does it take? Typical main panel swaps cost $2500-3500 in Alberta in 2025. Although if there is a complicated/unique electrical setup it can cost more. It takes a day, generally, to swap out the main panel. The power to building (in a residential setting) generally needs to be turned off for this work. Solar YYC will provide back up power to essential loads during that time. Final Thoughts: Is It Worth It? A main panel upgrade for solar might sound like a hassle, but it’s a one-time investment that opens the door to:– Greatly increase capacity for solar systems (greater energy savings)– A modern, code-compliant electrical setup For many Alberta homeowners, it’s the key to unlocking the full potential of solar energy.Need help figuring out if your panel is solar-ready?Contact Solar YYC for a free solar assessment. We’ll check your panel, calculate your home’s needs, and give you honest advice — with or without a main panel swap.