What Is the Purpose of an Electrical Sub Panel?

Electrician working on a circuit breaker panel

The main service panel distributes power from the utility company to branch circuits in a building. An electrical sub panel, however, serves a more specific area of a home or a separate unit on your property. It has its own circuit breakers. Similar in appearance and function to a breaker panel, a sub panel (or satellite circuit breaker panel), is installed within the part of a structure it serves.

How a Sub Panel Differs from the Main Panel

The main panel, or service entrance panel, is the junction point between your home electrical system and the grid. A sub panel works in much the same way, although it doesn’t provide its own energy. All power that goes through the sub panel is received from the main panel.

Why Do You Need an Electrical Sub Panel?

The sub panel is directly connected to the main service panel and is fed by a double-pole 24-volt breaker. Additional branch circuits are created by the sub panel. Some of the reasons for installing one include:

  • Convenience: Placing a sub panel in a house addition, garage, or outbuilding enables you to access the panel at this location. Appliances, outlets, or light circuits can be managed without going to the main service panel. It’s also easier to reset breakers serving power tools and heavy machinery.
  • Capacity: If all the breaker slots in the main panel are full, a sub panel allows you to add more circuits. For example, if you link a 60-amp breaker to the sub panel, you can divide the amperage among as many circuits as the panel will support. Distributing circuit capacity this way also reduces the risk of overloads and fires.
  • Time/Cost Savings: During construction or renovation, installing a sub panel reduces the number of “home runs” back to the service panel. Running a single high-amperage circuit is cost-effective. Otherwise, running three or four separate circuits from a remote area increases material and labor costs.

A sub panel not only improves safety and convenience. It prevents overcrowding of the main panel and splits power use across different sections of your home.

Installing/Servicing a Sub Panel

Electrical sub panel installation is not a recommended DIY project. It requires professional experience to do correctly. But to install a sub panel, two hot wires must be connected to the 240-volt double-pole breaker, which is located in the main panel; neutral and ground wires are required as well. A three-wire cable is run to the main breaker or lugs in the sub panel. Power is fed from here to two hot bus bars, to which individual circuit breakers are connected so that power can be distributed to branch circuits.

Should I Have My Sub Panel Inspected?

Your sub panel should be inspected regularly by a licensed electrician. There can be issues just as with the main service panel, including improper wiring connections, corrosion, and wear and tear. Most homeowners don’t know the subtle signs of danger to look for. A routine maintenance inspection allows a technician to spot minor issues, correct them before they get worse, and prevent major damage to your electrical system.

Contact Express Electrical Services

We help with electrical panel upgrades or sub-panel installation in Southern California. Since 1982, we’ve provided dependable, high-quality electrical services for homes and businesses, from minor repairs to rewiring and electrical remodeling projects. You can expect upfront pricing, no hidden fees, and fast service from highly trained, well-equipped technicians. Emergency service is available 24 hours a day, 7 days a week, while we offer a 100% satisfaction guarantee. Call 323-727-7799 for help with electrical sub-panel installation, repair, or maintenance.