We list these common electrical terms roughly in the order that they are observed, from the electrical utility company’s overhead wires and pole to the building receiving electrical power to its electrical panel, and in the panel to individual circuit breakers which provide power to and protect individual electrical circuits that distribute electrical power throughout a building. Here a local electrician in Los Angeles will give you each variable.
Electrical Service Drop: the overhead electrical service conductors from the last electric utility pole (or other aerial support) to and including splices if any, connecting to the service entrance conductors at the building. These wires usually belong to and are the responsibility of the electric utility company.
Service-Entrance Conductors, overhead system: the service conductors (wires) between the terminals of the service equipment (main electrical panel) and a point usually outside of the building, clear of building walls, where the wires are joined by tap or splice to the service drop (the wires from the utility company). These are the electrical wires coming down the building exterior from a mast-head connection point to the electrical meter, and continuing inside to the main electrical panel or service switch. These wires normally belong to and are the responsibility of the building owner.
Service Conductors: wires connecting service point (such as the outside electric meter) to the main service disconnect (such as the main breaker in the main electrical panel). These are wires bringing electrical power from the electric meter into the electrical panel.
Service Equipment: usually the circuit breaker(s) or switches and fuses used to connect to the load end of service conductors coming to the building. This is the main electrical switch, fuse, or breaker, usually in the main electrical panel but sometimes installed as a physically separate switch before the main electrical panel.
Circuit Breaker: a device designed to open and close (turn off or on) an electrical circuit by non-automatic means (a physical toggle switch) and to open the circuit automatically (internal trip mechanism) on a predetermined overcurrent without damage to itself when properly applied within its rating. (That is, a 15A circuit breaker is expected to protect a 15A circuit, not something else).
Branch circuit: are the conductors (electrical wires, hot, neutral, ground) between the final overcurrent device, protecting the circuit (a circuit breaker or fuse in the electrical panel) and the outlet(s). A general purpose branch circuit is an electrical circuit that supplies two or more receptacles or outlets for lighting and appliances. In other words, the wires that bring power from the electrical panel to one or more points in the building where it will be used to power a light, power something plugged into an electrical outlet, or to an individual appliance.
Call a local electrician in Los Angeles at United Plumbing Heating Air & Electric for additional electrical component questions.