The electrical service, also called the breaker box or fuse box, is where power first enters your home. This panel handles the incoming power (measured in amps) and distributes it to the individual circuits that run throughout your house.
When examining your breaker box, start by counting the over head utility wires. If there are three this indicates a single phase system and two indicates high leg.
Main Service Panel
The main service panel, also known as the breaker box or load center, is where all incoming electricity in a home flows through. In the old days, fuses were used in these panels, but today’s modern electrical system uses circuit breakers, which are far safer than fuses and provide more flexibility.
The panel has a metal door that is securely attached to the wall at shoulder height, and it’s filled with switches that control different areas of the house. This is where you can turn on and off power to outlets and appliances throughout your home.
The panel will have a sticker indicating its maximum amperage capacity, typically 100, 150, or 200 amps. It will also have a directory of the circuits that are connected to it, and this information is crucial for any professional who performs a home inspection. This allows them to efficiently locate the devices and circuits that are connected, resulting in less time spent on diagnostics.
Circuit Breakers
The circuit breakers in your service panel are lever-operated switches that can open (trip) under certain conditions, such as an overloaded circuit. When a circuit is overloaded, a high-powered device like an electric hair dryer or your annual Christmas lights might draw more current than the circuit can handle, leading to tripping of the switch.
A breaker’s trip coil senses this and energizes to generate a magnetic force that pulls the moving contact away from its fixed one, opening the circuit. This disconnects the flow of electricity, preventing damage and eliminating fire hazards. Circuit breakers are built to safety specifications to ensure that they can interrupt power at a maximum of 250% of their rated capacity and withstand the heat of an electrical arc while opening the contacts. A White Electric electrician can assess your circuits and redistribute the load to prevent overloading. Our technicians are always up to date on the latest electrical code requirements.
Service Wires
Whether your home is connected to the electric grid overhead or underground, the power that enters your house through those wires has to go through an electric meter before reaching your home’s main service panel and circuit breakers. Those wires can be damaged by weather or rodents, so it’s important for homeowners to understand who is responsible for repairing them, and that repairs should happen promptly to prevent electrical hazards.
Overhead Service Wires
Three insulated wires—live, neutral, and ground—run from the power pole to your house. They may arrive overhead via a weatherhead and a conduit, or they may run underground as service-entrance cables (SER or SEU).
Those wires carry high voltage electricity, so it’s essential that their connections are solid. During an inspection, the inspector will check that those connections are good, that there are proper clearances around them, and that the conductor insulation and cable sheath are not deteriorating.
Meter
A meter provides important information to power companies about how much energy is being used. It can also provide a useful tool for residents to help optimize their energy consumption.
Although most modern meters are digital, older designs may be mechanical in nature and use some kind of pointer device to show measurement quantities. The display mechanism is often referred to as a “movement.” Electromagnetic movements work on the principle that current flowing in one direction through the movement’s metal core will generate a magnetic field and cause the needle to deflect. Other types of meter movements are polarity-insensitive, such as the D’Arsonval and Weston iron vane designs.
In order to standardize the length of a meter bar, an international prototype was created made from a mix of platinum and iridium for added stability and durability. Since then, the length of a meter has been defined by hewing closely to the original prototype.
