An electrical panel — also called a breaker box, load center, or service panel — is the central hub where power from the utility enters your home and gets distributed to individual circuits throughout the house. It contains a main breaker that controls all incoming power and a series of individual circuit breakers that each protect a dedicated circuit running to specific areas or appliances.

What the Panel Actually Does

Your utility delivers electricity to your home at a high voltage through the service entrance — the weatherhead, meter, and main service conductors. The electrical panel steps that service into the branch circuits your home uses. Each breaker in the panel is rated for a specific amperage: 15 or 20 amps for most household circuits, and higher ratings (30, 40, 50 amps or more) for large dedicated loads like dryers, electric ranges, water heaters, EV chargers, and HVAC equipment.

When more current flows through a circuit than its breaker is rated for — because too many appliances are running, or because of a wiring fault — the breaker trips and cuts power to that circuit. This protects the wiring from overheating, which is the primary cause of electrical fires.

What’s Inside the Panel

Opening a panel reveals several key components:

  • Main breaker — A large double-pole breaker (usually 100, 150, or 200 amps) that controls all power entering the panel. Shutting it off cuts power to the entire house without going outside to the meter.
  • Hot bus bars — Two metal bars running down the center of the panel that carry the two legs of 120-volt power from the utility. Single-pole breakers connect to one leg; double-pole breakers span both.
  • Neutral bus bar — The bar where neutral wires from each circuit terminate. In the main panel, the neutral and ground buses are bonded together.
  • Ground bus bar — Where bare copper or green ground wires terminate. The grounding system provides a safe fault path back to earth.
  • Individual breakers — One per circuit, labeled to identify what area or appliance each controls.

Panel Sizes and Service Capacity

The main breaker rating tells you the maximum amperage your panel can handle — and, by extension, the maximum power your home can use at any one moment. Older homes in Denver and across the Front Range were commonly built with 100-amp service, which was adequate for the electrical loads of the 1960s through 1980s. Modern homes typically have 200-amp service, and some larger homes or those with heavy electrical loads (EV chargers, electric heat, large workshops) may need even more.

If your home has 100-amp service and you’re adding a heat pump, an EV charger, or a large addition, a service upgrade may be necessary before the new loads can be added safely.

Signs Your Panel Needs Attention

Most homeowners don’t think about their electrical panel until something goes wrong. These are the warning signs worth paying attention to: breakers that trip frequently or won’t stay reset; a panel that feels warm or makes crackling or buzzing sounds; a burning smell near the panel; visible corrosion, rust, or scorch marks; a fuse box instead of a breaker panel; or a panel manufactured by brands known for reliability problems (Zinsco and Federal Pacific Electric panels are the most commonly cited).

When to Call an Electrician

Electrical panels should only be worked on by a licensed electrician. The interior of a panel contains live conductors even when the main breaker is off — the wires entering from the utility remain energized until the utility shuts off power at the meter. This is not a DIY project. Any panel work — adding circuits, replacing breakers, labeling, or upgrading — requires a permit in Colorado and must be inspected after completion.

Done’s licensed electricians serve the entire Denver metro and Front Range. If you have questions about your panel’s capacity, age, or condition, our panels and wiring services page is a good starting point. For urgent panel issues, our emergency electricians are available when you need help right away.