The short answer: A dedicated circuit is one breaker that powers one outlet and nothing else. It is the safest place to plug in a solar kit, because devices share the wire. You can usually find out whether you have one in about 15 minutes with a lamp, a breaker panel, and a helper.

Why it matters

Your home's wiring is protected by a circuit breaker. The breaker watches the power coming from the panel and trips if the wire is overloaded.

Plug-in solar adds a second source of power at the outlet. The breaker cannot see that power. On a shared circuit, solar current and panel current can both flow through the same stretch of wire, and the total can go past what the wire is rated for without the breaker ever tripping.

Here is a simple example. A 15-amp breaker allows 15 amps from the panel. A 1,200-watt system adds about 10 amps from the solar side. On a shared circuit, part of the wire could carry up to 25 amps while the breaker sees only 15. A dedicated circuit with a single outlet avoids this, because nothing else on the wire pulls power.

Why some state laws mention it: Some state laws allow larger systems only when they are on a dedicated circuit. Your state guide says if that applies to you.

Dedicated or shared: which do you have?

How to check your panel

It's easy. You only need to read the labels and flip breakers.

1. Find your breaker panel. It is often in a garage, utility closet, basement, or hallway. Renters: if the panel is locked or outside your unit, ask your landlord or property manager.
2. Plug a lamp or a radio into the outlet you want to use. Leave it on so you can see when the power drops.
3. Flip breakers one at a time. Turn one breaker off, see if the lamp goes out, and turn it back on if not. When the lamp goes out, you have found the outlet's breaker.
4. Walk through your whole home with the breaker off. Check every other outlet, light, and appliance, including the bathroom, garage, porch, and other rooms. Use the lamp or a plug-in outlet tester.
5. Decide. If only that one outlet lost power, it is almost certainly a dedicated circuit. If anything else lost power, it is shared.
6. Note the breaker size. The handle is stamped with 15 or 20. Write it down, since your installer or the product instructions may ask for it.

Do not trust the labels alone. Panel labels are often wrong or out of date, which is why the walk-through in step 4 matters.

What if you do not have a dedicated circuit?

You have three options:

• Add a dedicated circuit. A licensed electrician can install one, often to a spot near a balcony, patio, or garage wall. This is the best long-term setup.
• Choose a system designed for shared circuits. Some systems have built-in overload protection for shared circuits. The product page and installation instructions say so. If they do not, assume the system needs a dedicated circuit.
• Choose a smaller system. Some state laws let very small systems skip wiring changes. Check your state guide.

When to call an electrician

• You cannot tell whether a circuit is dedicated.
• The breaker trips when the solar system is running.
• The outlet feels warm, buzzes, or has scorch marks.
• Your state or system requires a licensed electrician or a special receptacle.
• You want a new outlet installed.

Learn more: Plug-in solar safety, Plug-in solar certifications, Glossary. This article is general information, not legal or electrical advice. Rules vary by state, utility, and building, so check local requirements and consult a licensed electrician where needed.