A solar quote sometimes states that the main electrical panel or the entire service must be upgraded before the system can be installed. This upgrade, along with the rest of the tie-in between the solar system, your home's wiring, and the utility grid, is our part of a solar or battery project. It encompasses how the inverters or micro-inverters connect to your panel, the external disconnect switch required by the utility, and, for battery storage systems like a Tesla Powerwall, defining which critical circuits remain active when the grid goes down.
The primary constraint is often the existing breaker panel. The National Electrical Code strictly caps the amount of solar power a panel can accept based on the busbar's physical rating and the size of the main breaker. A standard 100-amp panel frequently lacks the capacity to accept solar backfeeding, leaving you with the option of a panel or service upgrade, down-sizing the main breaker if your home's electrical load allows, or performing a line-side tap made ahead of the main breaker.
Utility companies like Georgia Power, Cobb EMC, and Marietta Power each mandate a formal application and explicit approval before any solar array can run in parallel with the grid. Consequently, the newly installed system must remain completely switched off until your utility company officially grants permission to operate.
What This Covers
- Connecting solar inverters and micro-inverter circuits to the panel
- Panel and service upgrades to make room for solar
- Utility-required disconnect switches
- Home battery connections, such as a Tesla Powerwall
- Backup gateways and panels for backed-up circuits
- Repairs to the wiring, breakers and disconnects of an existing system
Signs It’s Time to Call
- A solar company wants the panel or service upgraded first
- A battery is being added to solar you already have
- Certain circuits need to stay on in an outage
- A solar breaker or disconnect keeps tripping
The Process
Size Up the Panel
We evaluate the main electrical panel, the utility meter, and the overall service size alongside the manufacturer specifications of your inverters or battery. A formal calculation determines whether your existing panel can legally and safely accept the solar system.
Apply to the Utility
The formal interconnection application is submitted to your utility company with a detailed one-line diagram and full equipment specifications, while the electrical permit goes to your local building department. Georgia Power explicitly advises customers to avoid purchasing equipment until the utility has reviewed and approved this application.
Wire the Disconnects and Gateway
All external disconnect switches, protective conduit, wiring, new breakers, and any backup subpanels or battery gateways are installed and clearly labeled to comply with safety codes.
Wait for Permission to Operate
Following a successful inspection by the local building department, the utility company performs its own checks and will replace or reprogram your meter where necessary. The solar and battery system remains off and only goes live once the utility officially grants its permission to operate.
Common Questions
What does the utility require before solar or a battery is connected?
Each utility has its own steps. Georgia Power takes an interconnection application through its online portal and requires a signed agreement, an inspection by the local building department, its own permission to operate, and an outdoor disconnect switch it can reach and lock. Cobb EMC asks members to start its interconnect agreement at least 45 days before the system is to be connected, and it swaps the meter after the local inspection. Marietta Power requires an application and agreements approved before interconnection, and an external disconnect its crews can lock.
Georgia Power serves much of the Atlanta area, but some neighborhoods are on an electric co-op or a city utility instead. Requirements change, so check your own utility's current documents.
Will my solar panels keep the power on in an outage?
Not without a battery or other backup equipment. A grid-tied inverter is required to shut down when utility power is lost, so it can't send power onto lines that crews may be working on. That applies to micro-inverters, the small inverters mounted under each panel, as well as central inverters. To keep running, the house needs a battery with a gateway or transfer switch that disconnects it from the grid first. Georgia Power requires that switch to be a break-before-make type.
Can a battery be installed without solar, and where does it go?
Yes. A battery can charge from the grid and carry the house, or part of it, through an outage. It still needs the utility's approval, because it's connected to the grid.
Building and fire codes limit where a battery can go. Generally a garage, a utility space or an outside wall is fine, and bedrooms and closets aren't. Some manufacturers supply and support their batteries only through installers they've approved, so settle early who supplies and commissions the battery and who does the electrical work around it.