- The electricity that flows to your house is called alternating current (AC) electricity. AC electricity switches directions rapidly, going from negative to positive and back again 60 times a second. Before the electricity can get to your house, it has to travel miles along power lines. The power lines are made out of copper wire, which is good at conducting electricity. Nevertheless, the further electric current travels, the more power is lost. To minimize electric power loss, the power companies increase the electronic "pressure" or voltage. High-voltage electricity is much less susceptible to resistance, so less power is lost. High voltage is hazardous, so when the electricity reaches your house, its voltage is reduced to a fairly safe 120 volts.
- Electric power runs through your circuit breaker or fuse box, which sends it to all the outlets in your house. Outlets are either two- or three-prong, meaning they either just have two slits or have two slits and a small hole. One slit has a metal contact attached to the live wire. The live wire is what actually brings electricity into the house. The second slit has a contact attached to a second wire called the neutral wire, which brings electricity back out again. Three-prong outlets also have a ground wire, which is used to protect appliances and users from stray voltage.
- When you plug appliance into the outlet, the prongs reach in and touch the electrical contacts. Electricity flows into the appliance through the live wire, does whatever task it is supposed to do and flows back out through the neutral wire. The neutral wire brings it all the way back to the power plant, completing the circuit. If there is an internal short circuit in an appliance, sometimes electricity can get conducted into the case of the appliance, which could electrocute someone coming into contact with it. That is when a ground wire comes in handy. The stray electricity is conducted through the ground wire into a pipe or ground rod, which disperses it harmlessly into the earth. Surge suppressors also use ground rods. If the voltage coming through the power line jumps too high, the surge suppressor sends the excess electricity into the ground.
