Remember when it was your job to fill the swimming pool for younger siblings? Oh, the pain — the baseball field and all your friends were waiting. After all, filling a pool eight feet in diameter and two feet deep takes some time. So, you decide to drag out the garden hose, secure it so it won’t fall out, turn on the water, and then sneak out to the front yard for a couple of innings. Unfortunately for you, little Bobby has decided to choose this day to retaliate for all the brotherly torture you bestowed upon him this summer. Bobby gets an ice pick out of Mom’s kitchen drawer. With the deftness and speed of a 20-year lawn care guy, he aerates the garden hose — with two hundred holes. How much water do you suppose is making it to the pool now?
This example illustrates what can happen to wire when its insulation breaks down. Electrical current leaks out. The wire is called a conductor, and its job is to transport electric current. Insulation protects the wire and its job is to “resist,” or keep the current from leaking out. All insulation will leak some current, even if it is a minute amount. Some factors that cause insulation to break down include moisture, dirt, acid, humidity, mechanical damage, and vibration.