Electrical Service is the conductors and equipment that deliver electric power from a utility to the wiring system of a building or structure. This is a very broad definition and the National Electrical Code (NEC) addresses a lot of areas within this definition. This article focuses on the specific components of the electrical service that is typically found at a residential house.
A common sight in many neighborhoods across the country are electric utility trucks and crews working to restore electrical services after an outage. These are some of the most dedicated and professional people society has to offer and work in all kinds of weather to keep us powered up and enjoying life.
During these times of outages we often focus on the truck drivers and line workers and their ability to get the electrons flowing again as soon as possible. However, what many do not realize is that the process of restoring a power outage takes time to complete. It can take hours or even days to get the electricity restored to a single residence, apartment complex or business. This is a result of the complex task that the electric utility company must perform to bring back the power to the entire area.
The electrical service to a home or business is typically fed through a main panel that splits the current into individual circuits that run throughout the house, powering light fixtures and outlets as well as other devices. This panel is usually a gray metal box located somewhere inside the home, often in a garage or basement. In some cases the panel is contained in a finished cabinet mounted to the wall. The main panel is where the circuit breakers are stacked and controlled with a lever that places them in an “On” or an “Off” position. It also contains the meter and other control equipment. The main breaker has a label on it that indicates the amperage capacity of the service, usually 100 amp or 150 amp for residential construction.
The electrical service to a home or business can be supplied by either underground or overhead conduits. The conduit size is typically based on the cable size that is being provided by the utility company. The point at which the service wires connect to the customer’s service entrance conductors is called the service point. The NEC regulates the installation of this connection and the premises wiring up to that point. In most situations, the NEC requires that a revenue meter be included as part of this service and the owner is required to pay for the usage based on the read on the meter.