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115 Electrical Safety for Employees: Basic
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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.

Electrical overloads can cause fires.

When too many devices are plugged into a circuit, the electrical current can cause the wires to heat up to a dangerously high temperature. Similarly, if a tool draws too much current, it will also result in the wires becoming excessively hot.

The wires can become hot enough to cause a fire. If the insulation around these wires melts, it can lead to arcing. This arcing has the potential to cause a fire in the area of the overload, which can happen even inside a wall

To prevent excessive current in a circuit, either a circuit breaker or a fuse is used. When too much current flows through the circuit, the breaker 'trips,' acting like a switch to open the circuit. In the case of a fuse, an internal part melts under overload conditions, also opening the circuit. Essentially, both breakers and fuses serve the same purpose: they open the circuit to shut off the electrical current and prevent potential hazards.

If the circuit breakers or fuses are too large for the wires they are meant to protect, they may fail to detect an overload in the circuit. This means the current will not be shut off as needed. Such overloading can lead to the overheating of circuit components, including the wires, potentially causing a fire.

You must recognize that a circuit with improper overcurrent protection devices - or one with no overcurrent protection devices at all - is a hazard.

Real-Life Accidents

At approximately 7:45 a.m. on November 27, 2021, an employee worked in the Flower Room moving flower racks around to perform tasks such as watering. While moving a rack, an electrical cord stretched and pulled from its mount in the junction box, exposing a live wire and causing a section of lighting to go out. The employee climbed a ladder and attempted repositioning the cord that pulled free and inadvertently touched the live wire. The employee was shocked and hospitalized to treat these injuries.
At 10:00 a.m. on January 11, 2022, an employee was adding a light to a new bathroom when he touched 2 wires together to attempt to trip the breaker. The employee received a 277 volt shock to his hand and was transported to the hospital, where he was held for observation and released.

Knowledge Check Choose the best answer for the question.

1-10. Which of the following would be the most likely indication of an electrical circuit overload condition?