Overload Hazards
Overloads in an electrical system are hazardous because they can produce heat or arcing.
Wires and other components in an electrical system or circuit have a maximum amount of current they can carry safely. If too many devices are plugged into a circuit, the electrical current will heat the wires to a very high temperature. If any one tool uses too much current, the wires will heat up.
The temperature of the wires can be high enough to cause a fire. If their insulation melts, arcing may occur. Arcing can cause a fire in the area where the overload exists, even inside a wall.
In order to prevent too much current in a circuit, a circuit breaker or fuse is placed in the circuit.
- If there is too much current in the circuit, the breaker "trips" and opens like a switch.
- If an overloaded circuit is equipped with a fuse, an internal part of the fuse melts, opening the circuit.
Both breakers and fuses do the same thing: open the circuit to shut off the electrical current.
If the breakers or fuses are too big for the wires they are supposed to protect, an overload in the circuit will not be detected and the current will not be shut off. Overloading leads to overheating of circuit components (including wires) and may cause a fire.
Overcurrent protection devices are built into the wiring of some electric motors, tools, and electronic devices. For example, if a tool draws too much current or if it overheats, the current will be shut off from within the device itself. Damaged tools can overheat and cause a fire.
Knowledge Check Choose the best answer for the question.
5-9. An electrical circuit may blow a fuse too late causing an overheat condition if the circuit breaker or fuse is _____.
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