The service panel is the point that connects the service wire or service drop, which is the main wire coming from the outside into the house, to the exit wires that split off and service different parts of the house. These exit wires are called branch circuits or branch wire circuits.
A service panel is the central distribution point for all branch circuits of the House. Branch circuits are connected to the service panel via circuit breakers. The circuit breakers have no purpose other than safety: they immediately cut off electricity to branch circuits in the event of overload.
Service wire lugs are a major component of the service panel.
Service wire lugs connect the service drop to the service panel, and are highly dangerous points that should never be touched. The reason for this is that it is impossible to turn off the power to the service wire lugs. Main service is continually on, except in the event of an overall power failure or if you make a special request with the power company to shut off power from the street.
Not only that, but service wire lugs relay intense, concentrated power. Unlike branch wire circuits, which are just a portion of the entire electrical service to the house, the service wire lugs represent every single ampere of electricity coming into the house.
