Many homeowners who are unfamiliar with construction and wiring are timid when it comes to electrical work. It makes perfect sense to have a healthy respect for electricity—it can be dangerous if you don't understand it.
To give you confidence and a little knowledge to help you discuss electrical problems with an electrician, let’s explore how the service panel (or panel box) controls your home's electrical system.
The Service Panel
After passing through the electric meter, the local electrical utility provides electricity to your house through the service panel (also called the distribution center). The panel, which is usually located in a garage, basement or utility room, distributes electricity through individual circuits that run throughout your house.
The service panel in most homes contains circuit breakers, which look like little switches. Older homes may contain fuses, but they serve the same purpose as circuit breakers—to stop the flow of electricity when there is a problem.
As a homeowner, you need access to the panel for three tasks:
to shut off power to the whole house if needed (you do this by switching off the large breaker);
to reset a circuit breaker that trips; and
to turn off power to individual circuits when you are doing electrical work somewhere in the house.
You can also add new circuits to the panel box if there is room, but this is usually a job for a licensed electrician.
Why Do Circuit Breakers Trip?
If you plug too many appliances into a circuit, the system senses that they require more power than the circuit can accommodate and the circuit breaker trips, shutting off power completely. It’s a safety measure designed to protect the wiring in the circuit, as too great a demand can cause the wires to overheat.
Each circuit has a limit of how much power it can handle. You will find that limit printed on each breaker. The number represents the ampere, or amps, which measure the rate or quantity of electrical flow. The number printed on the main breaker is the upper limit your house’s service can accommodate.
For example, a 15-amp circuit is a light-duty circuit that may power s