Circuit Protection Devices
Circuit protection devices limit or stop the flow of current automatically in the event of a ground fault, overload, or short circuit in the wiring system.
Fuses, circuit breakers, ground-fault circuit interrupters (GFCIs), and arc-fault circuit interrupters are well-known examples of these devices.
Fuses and circuit breakers are designed to automatically open or break the circuit when an excessive current flows through them. In such cases, fuses will melt, and circuit breakers will trip, thereby opening the circuit. Their primary function is to protect conductors and equipment by preventing wires and other components from overheating. They also open the circuit to mitigate the risk of a ground fault.
Ground-fault circuit interrupters (GFCIs) are essential safety devices used in wet locations, construction sites, and other high-risk areas. These devices interrupt the flow of electricity within as little as 1/40 of a second to prevent electrocution. GFCIs work by comparing the amount of current entering and leaving electric equipment through the circuit conductors. If they detect a difference exceeding 5 milliamperes, the device automatically shuts off the electric power.
Arc-fault devices provide protection from the effects of arc-faults by recognizing characteristics unique to arcing. They function by de-energizing the circuit whenever an arc-fault is detected.
Knowledge Check Choose the best answer for the question.
2-4. Which of the following melts when too much electrical current flows through it?
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