Critical Loads Panel

A critical loads panel (also called a backup panel or essential loads panel) is a dedicated electrical subpanel that contains only the circuits you want to keep powered during a grid outage when using battery backup. It is a key component of any solar-plus-storage system designed to provide backup power.

When the grid goes down, your battery can only supply a limited amount of power. Rather than attempting to back up your entire home (which could drain the battery in hours), a critical loads panel lets you prioritize the most important circuits. Typical critical loads include the refrigerator, a few lighting circuits, Wi-Fi router, garage door opener, phone charging outlets, and any medical equipment. During an outage, the battery and solar panels supply power exclusively to this panel while the rest of the home remains off. Your solar installer will help you identify which loads to include based on your battery capacity and priorities. Some newer battery systems (like the Tesla Powerwall 3) can provide whole-home backup without a separate critical loads panel, but this depends on the battery’s power output and your home’s peak demand.