When you run out of breaker space or add a garage, workshop, or ADU, a subpanel is often the answer. Here’s what to know.
What is a subpanel?
A subpanel is a smaller panel fed from your main panel. It adds circuits and puts breakers closer to where the power is used — like a detached garage, workshop, or addition.
When you need one
- Your main panel is full — no room for new breakers
- You’re powering a garage, shop, ADU, or addition
- You want circuits closer to a specific area to reduce long wiring runs
- You’re adding several new circuits at once
Subpanel vs. panel upgrade
These solve different problems:
- A panel upgrade increases your home’s total capacity (e.g., 100A → 200A).
- A subpanel distributes existing capacity to more circuits or a new area.
Sometimes you need both — more total power and a subpanel to distribute it. An electrician’s load calculation tells you which. (See do you need a 200-amp upgrade.)
What it costs
A subpanel in Fremont typically runs $1,000–$3,000+, depending on the amperage, the distance from the main panel, and whether the run is indoors or to a detached structure.
Get it sized right
Feeder wire, breaker sizing, and grounding all have to be correct and to code. See our panel services, or get a free quote for your Fremont home.