Overloaded circuit

A circuit can become overloaded when there are more lamps and appliances on it than it can safely handle. When all the appliances are turned on, the wiring overheats and the fuse blows or the circuit breaker trips.

Short circuit

A short circuit occurs when a bare hot (live) wire touches a bare neutral wire or a bare grounded wire (or some other ground). The flow of current blows a fuse or trips a circuit breaker.

Helpful Diagnostic Hints

Plug fuses can provide clues to what made them blow:

• An overload melts the bridge.
• A short circuit blackens the glass.

Tracing a Short Circuit or Overload

A blown fuse or tripped circuit breaker is a signal that you may have either a short circuit or an overload in the electrical system.

• Look for black smudge marks on switch or receptacle cover plates, or for frayed or damaged cords or damaged plugs on lamps and appliances connected to the dead circuit.
• Replace a damaged cord or plug.
• Then replace the fuse or reset the breaker.
• If the circuit goes dead after an appliance has been in use for a short time, you probably have an overloaded circuit.
• Move some of the lamps and appliances to another circuit and replace the fuse or reset the circuit breaker for the first circuit.