If there are two pieces of metal that are close in proximity to each other, but don t connect, the current can jump between the two metal pieces. That is what is happening when you see that blue light spark when you plug an old cord into an outlet. This is called arcing. And while you may not blow a fuse, the heat from the arcing can become so extreme that it becomes a fire hazard. If it feels hot, that s a clue to check the wall outlet or plug on the appliance and make sure a connection is being made.
Every electrical wire is made up of two wires a hot wire and a neutral wire.
When the hot and neutral wires physically touch, there s a bang and a spark that s a dead short, Mike says. But like an overload, a short will also blow a fuse. A short can also cause problems with other lines in your house because the flow of energy is so tremendous. That s why circuit breakers are such a great thing they protect the wiring from those energy surges. The advantage is that when there is an overload on the line the circuit breaker is protecting, the circuit breaker trips a switch, Mike says.