Wiring Basics

Breaker Box

• The breaker box is the central point of any domestic wiring system. It is the location where the power feed comes in from outside the house and is broken up into separate circuits. Most breaker boxes contain one main breaker that can be tripped to turn off all power to the house, along with rows of smaller breakers, each of which represents a separate circuit within the house. Each breaker can be shut off without affecting the rest of them, allowing the homeowner to cut power to particular outlets or appliances while still being able to use everything else in the house.
  
  

Circuits

• Circuits are usually divided by convenience according to areas within the house. All the lights and outlets in a particular room might be on a single circuit. This isn't a hard and fast rule, and sometimes depends on the predilections of the electrician who wired the house. High-power users such as electric stoves and water heaters run on 220 volts and usually have their own dedicated circuits. Most breaker boxes have extra spaces in them where new circuits can be installed if an addition is built or more lights or appliances are added to the home.
  
  

Live, Neutral and Ground

• Standard residential wiring consists of three wires that are contained within a plastic casing. The live wire is in a black casing, the neutral wire is in a white casing, and the ground wire is bare copper. Because these three wires are contained in the outside casing, they can't be seen except where the wire is cut. When the ends of the wire are attached to the breaker box or to an outlet or appliance at the other end, the live and neutral wires are attached to opposite sides of the outlet or appliance and the ground wire is attached to a ground screw as a safety precaution.
  
  

Outlets

• Outlets are the basic consumer-friendly electrical component, designed to be used with no training in electricity. An outlet with nothing plugged into it is an incomplete electrical circuit. When a lamp is plugged into the outlet, the circuit remains incomplete until someone turns the lamp on. At that point, the circuit is completed and the electricity flows through the light bulb, creating light. One oblong slot in the outlet represents the live wire and the other represents the neutral wire. The circular hole represents the ground. Outlets are very safe unless you stick something made of metal into the holes and hold onto it.