Top
  • Clear All

Electrical Panel Upgrades for Solar

aerial view of two houses one rooftop with solar panels

More and more California residents are switching to solar every year--and for good reason! A solar panel system can offer utility savings, energy independence, and a reduced carbon footprint.

But switching to solar can be a big project. And sometimes going solar requires updating older parts of your home.

In this article we'll cover a frequently required update‚Ā†—electrical panel upgrades (also known as main service panel upgrades).

To understand why electric panel upgrades are so common, it first helps to understand how solar connects to your home.

How do solar panels connect to your home's electricity?


Solar panels produce DC electrical current. This current is passed to the inverter where it's converted into alternating current (AC). Alternating current is then passed to the home's electrical panel. From the panel (also known as a main panel or breaker box) power is distributed throughout the home.

The main circuit breaker panel distributes power to the entirety of the home. All of the home's power, from the grid or solar, flows through the main panel. It might be helpful to view the main electrical panel as a set of gates. These gates permit, and restrict, the flow of electricity throughout your home.

Some items in this example have been simplified. But it's easy to see why the main panel holds such an important role in solar installation!

What is a main panel upgrade?

In a main panel upgrade an electrician replaces (or adds) circuit breakers and/or wiring on the electrical panel. New circuit breakers are added when the old breakers can no longer support the electrical load.

For safety reasons, most electrical panels can be found in the utility room in your basement. You may also see them in the garage or the pantry. In some older homes, they may be located outside.

When do you need a main panel upgrade?

Electrical panels lose their ability to support the electrical load in two conditions.

1) Old breakers are wearing down. Resulting in a drop in total panel capacity.
2) New electrical load is being added to the home that the old panel can't support.

New electrical load is introduced to the home through a variety of activities. New power-hungry appliances, home renovations, or in our case, solar.

How do I know if I need a panel upgrade for solar?

The switch from standard electricity to a solar energy system begins with a preliminary inspection. A technician will begin by taking a close look at your electrical service panel. They will inspect your circuit breakers and wiring to ensure that everything is in good working order. They will test the service panel to make sure your system is ready to make the switch.

Signs that you will likely need a panel upgrade include:

  • 1) flickering or dim lights in the home.
  • 2) Needing to flip the breaker often.
  • 3) Home appliances appearing to be lacking full power.

What Makes an Electrical Panel Solar Ready?

Your electrical panel is solar-ready when it has available breaker slots, can handle the electrical load of solar, and follows the 120% rule. It might also be a good idea to consider future changing electrical needs even if the panel is currently solar-ready.

The 120% Rule


The 120% rule is a policy from the National Electrical Code (NEC) that dictates the minimum size of electrical panel allowed with solar.

The 120% rule states that you can’t have more than 120% of your solar system's expected production flowing through the panel busbars.

You might be wondering why your solar system would ever be producing more than 120% of what your home might require. Keep in mind that with solar energy production ramps up in the afternoon and then drops as night approaches. To offset your day's energy needs the solar energy system needs to produce a surplus in the afternoon to cover the remaining hour's needs.

Electric Panel Upgrades and Tax incentives

You can receive a tax credit for switching to solar energy. The tax credit is determined in proportion to the cost of your solar project. The cost of your panel upgrade can be included in the total system cost for your tax credit. This can result in significant cuts in total cost!

Additionally, if you work with SolarUnion, we offer panel upgrades at or even below cost. With SolarUnion we're never making a profit on necessary infrastructure upgrades as a part of solar projects.

Work with an expert for your electrical panel upgrade

If you're interested in going solar and have more questions about your panel, give us a call!