--- title: What Is A Subpanel? description: Sometimes, your main electrical panel requires additional preparation to install solar. This article will discuss subpanels, and why you might end up needing one. --- [Skip to content](https://knowledge.projectsolar.com/migration/what-is-a-subpanel#main-content) English Show submenu for translations ![project solar logo - for light bg.png\]](https://knowledge.projectsolar.com/hs-fs/hubfs/project%20solar%20logo%20-%20for%20light%20bg.png?height=20&name=project%20solar%20logo%20-%20for%20light%20bg.png) Open main navigation Close main navigation - English Show submenu for translations - projectsolar.com projectsolar.com Hello. How can we help you? - There are no suggestions because the search field is empty. 1. [FAQ](https://knowledge.projectsolar.com/migration?hsLang=en) 2. [Solar Basics](https://knowledge.projectsolar.com/migration/solar-basics?hsLang=en) 3. [Solar Insights: Deeper, More Technical Info](https://knowledge.projectsolar.com/migration/solar-basics?hsLang=en#solar-insights-deeper-more-technical-info) # What Is A Subpanel? ## Sometimes, your main electrical panel requires additional preparation to install solar. This article will discuss subpanels, and why you might end up needing one. ![What Is A Subpanel\_ ()\_13761810400027](https://knowledge.projectsolar.com/hs-fs/hubfs/What%20Is%20A%20Subpanel_%20()_13761810400027.png?width=688&height=577&name=What%20Is%20A%20Subpanel_%20()_13761810400027.png) While a main electrical panel is directly connected to the power grid, a subpanel acts as a waypoint between the main service panel and the electrical circuits further down the line. Many homes use subpanels to organize circuits into groups. Some solar customers will need a subpanel added to their home to have their system installed. ### Do I Need to Add a Subpanel? While drawing up the plans for your system, Project Solar’s engineering team will examine your home’s electrical network, (breakers, wiring, and capacity) to determine exactly how your solar system will be connected. They will also ascertain whether or not a subpanel will need to be added. If you have little to no available breaker space in your main electrical panel, it is more likely you will need a subpanel. ### Why Do I Need to Add a Subpanel to Install Solar? If our engineers determine you need a subpanel, it’s most likely because you do not have sufficient breaker space in your main panel. A main electrical panel has switches, or “breakers” that control specific circuits. It also has set spaces for these breakers to be placed and wired. When Project Solar ties your solar system into your main electrical panel, there will need to be breakers to switch on and off the system in case of fire or maintenance. If there aren’t any breaker spaces left in your main electrical panel, we’ll usually need to add a subpanel. Some main panels will only have one breaker–the “main breaker”--this is the main gateway for electricity flowing from the grid into your home. In this case, there is most often an existing subpanel with other breakers to control specific circuits. If a subpanel is required, Project Solar will generally add one in between the main panel and the existing subpanel. This is to ensure the subpanel is correctly sized for the correlating solar system. In rare cases, adding a subpanel can help avoid the need for a [main panel upgrade.](https://knowledge.projectsolar.com/what-is-a-main-panel-upgrade?hsLang=en) ### How Much Does a Subpanel Cost? The base cost for a subpanel addition is $800.   - [Solar Basics](https://knowledge.projectsolar.com/migration/solar-basics?hsLang=en#main-content) - [Solar 101: The Fundamentals](https://knowledge.projectsolar.com/migration/solar-basics?hsLang=en#solar-101-the-fundamentals) - [Solar Insights: Deeper, More Technical Info](https://knowledge.projectsolar.com/migration/solar-basics?hsLang=en#solar-insights-deeper-more-technical-info) - [Custom Solar Projects](https://knowledge.projectsolar.com/migration/custom-solar-projects?hsLang=en#main-content) - [Full Service Install](https://knowledge.projectsolar.com/migration/custom-solar-projects?hsLang=en#full-service-install) - [Financial Information](https://knowledge.projectsolar.com/migration/financial-information?hsLang=en) - [Project Solar Power Bank Products](https://knowledge.projectsolar.com/migration/project-solar-power-bank-products?hsLang=en) - [Additional Info](https://knowledge.projectsolar.com/migration/additional-info?hsLang=en) [![Chill listening crop-3](https://knowledge.projectsolar.com/hs-fs/hubfs/project%20solar%20logo%20-%20for%20light%20bg-1.png?width=201&height=17&name=project%20solar%20logo%20-%20for%20light%20bg-1.png "Chill listening crop-3")](https://projectsolar.com) At Project Solar, we aim to make solar so incredibly easy and affordable that it becomes the financially prudent energy option for all homeowners. Copyright © 2026, Project Solar