What Is Electrical Service?

Electrical service is the network of wires and equipment that provides electricity to your building. This includes the delivery system that transports power to your home and the metering that tracks your energy use.

It is important to understand how your electric system works and who is responsible for maintaining it. Always be careful when touching exposed service wires.
The Main Service Panel

The main service panel is the heart of a home’s electrical system. It distributes power from the utility to the branch circuits that supply the lights and other devices in your house.

The two thick wires that bring electricity into the panel each carry 120 volts, or 240 volts total. They connect to electrically conductive bars inside the panel called hot buss bars. The main breaker controls the flow of electricity from these two wires to the hot buss bars. The breakers inside the panel then control the flow of electricity to the individual branch circuits.

The electrical service panel is a metal cabinet with a hinged door. It should never be opened by anyone except a qualified electrician. It is dangerous because the mains that bring electricity into the panel remain live (carrying deadly current) unless the panel is shut off. The cover on the service panel also prevents people from getting too close to those mains, and it requires a large space for working around them.
The Meter

The meter is the watt-measuring device that tracks your power consumption month to month. It can be old-fashioned with numbered dials or new, state-of-the art digital and can even be read remotely by the utility company. The meter must be installed and wired by a certified professional.

The electrical panel is the central hub that delivers electricity to switches, outlets and appliances throughout a home. Located in a garage, basement or utility room, the panel contains circuit breakers that can trip (cut off) power to faulty circuits, preventing fires and other electrical problems. The panel also includes a grounding connection, which provides a path of escape for electricity in the event of an overload or short circuit and protects people working on the system as well as appliances and equipment connected to the system.

The service drop, mast and meter socket are the responsibility of the power company. However, a homeowner must have a weatherproof disconnect right after the meter socket that is rated to handle the amperage coming into the house.
The Service Drop or Lateral

The service drop or lateral is where the power lines run down to your house. These can be overhead or underground. The power company runs two hot wires and a neutral from their line to their transformer, then down the power pole or into the manhole. The conductors can be bare wire, old three wire service drops, or multiconductor cable (with no overall jacket) called triplex. Most modern new construction and many existing homes have a buried electrical service.

These cables are surrounded by a strain relief cable to support the weight of the wires and help reduce damage to the lines. Homeowners are not allowed to work on the power company’s service drop or lateral, and the power in these cables can only be shut off by the utility.

The NEC requires a plaque at each point of attachment or entry on both the service drop and lateral. The plaques should indicate the following NEC definitions:
The Wiring

Wires are what connects everything associated with electricity. They are flexible and allow for the transfer of power between different devices such as switches, outlets, lights and fans. Wires come in varying sizes and compositions depending on their purpose. It is important to note that a wire that is not connected to an outlet or switch should not be touched because it will still carry current. If touched it could electrocute you.

The next device in the electrical service is the main service panel also referred to as a breaker box or fuse box. This device is responsible for distributing power throughout your home via the individual branch circuits. It can be found in a utility area or sometimes enclosed within a finished cabinet mounted on the wall.

When performing a site assessment try to count the over head utility wires on the pole. If there are two it is likely that you have a single phase service and if there are three it is probably a dual phase service.