Residential Wiring – Overview
How power reaches a home – Power plants produce large amounts of electricity.  This electricity is transported to sub-stations throughout a region at a very high voltage.  The electricity eventually reaches a transformer.  The transformer converts the high voltage electricity into 120 volts and is transported via power lines, above or below ground, to the home.


The current enters the home first through the electrical meterand then into your service entrance panel or breaker box.  The service panel contains circuit breakers (also known as “overcurrent protection devices”).  Some older homes have service panels which contain fuses.


The homeowner’s interaction with the service panel should be only to switch off and on either the main power or power to individual circuits.  This is done by actuating the main breaker, which controls all the electricity supplied to the home, or an individual circuit breaker, which controls electrical power to specific areas within the home also know as branch circuits.
Circuits in the home (AKA Branch Circuits)
A “branch” circuit is an individual circuit that “branches” from the service panel (breaker box) to receptacles, switches, light fixtures and other devices.
There are three types of branch circuits in your home:
Lighting Circuits:   general purpose circuits that power all of the light fixtures as well as receptacles.
Small appliance circuits: circuits that power receptacles for small appliances and power tools in the kitchen, laundry and workshop.
Individual appliance circuits: circuits which are each dedicated to a single major appliance such as an electric range, electric clothes dryer or whole house air conditioner.