The electricity is always waiting in the wires to be used. Electricity travels in a circuit. When you switch on an appliance, you complete the circuit. Electricity flows along power lines to the outlet, through the power cord into the appliance, then back through the cord to the outlet and out to the power lines again. Insulators Electricity does not travel easily through certain materials like special rubber, plastic and glass.
Insulators keep electricity in power lines.
Glass, plastic or ceramic insulators high up on power poles keep electricity from traveling down the pole to the ground. If an insulator breaks, or a power line becomes disconnected from the insulators that hold it up, the line can fall to the ground and energise the area around it with a lot of electricity. If you touch a downed line or even the ground near the line you could be hurt or killed. If a power line falls on a car and you touch the car and the ground at the same time, you would also get a shock. Volts, amps, and watts measure electricity.