Do I need a transformer upgrade in order to go solar?
Your transformer's kVA rating determines the maximum solar system size it can handle — if the system exceeds that limit, you'll need to upgrade the transformer or downsize the array.
Whether you need a transformer upgrade depends on the relationship between your transformer's capacity and the size of the solar system you want to install. The key number is your transformer's kVA (kilovolt-ampere) rating, which sets the upper limit on how much power can flow through it.
Here's the math: if you have a 2,000 kVA transformer, it can handle up to a 2,000 kW-AC solar system. To convert that to the DC rating you'll typically see in solar proposals, multiply by the inverter's AC-to-DC ratio — usually around 1.20. So a 2,000 kW-AC limit translates to roughly 2,400 kW-DC.
If your proposed solar system exceeds your transformer's capacity, you have two options: purchase a new transformer or reduce the size of the solar array. Transformer upgrades are typically paid by the building owner (not the utility), so this is an important cost to identify early in the project. Your solar provider should flag this during the proposal process, but knowing your transformer's kVA rating upfront helps you set realistic expectations for system size and project cost.