An electrical panel (also called a breaker box, distribution panel, or service panel) is the central hub that receives electricity from the utility and distributes it to circuits throughout a building. The panel contains circuit breakers or fuses that protect individual circuits from overloads—when a circuit draws too much current, the breaker trips, disconnecting power before wiring overheats and potentially causes fire. Modern panels use circuit breakers that can be reset; older panels may have fuses that must be replaced. Panel capacity (measured in amps—commonly 100, 200, or 400 amps for residential) determines how much electrical load a building can safely handle. Municipalities regulate electrical work through permits and inspections, and panel upgrades often require permits. Licensed electricians must perform most panel work, as improper installation can cause fires, electrocution, or code violations.