How Overload Conditions Occur And Electrical Protective Devices
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 a 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.
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.
You must recognize a circuit with improper overcurrent protection devices, or one with no
overcurrent protection at all, is a hazard!
