What is the name of the device that senses the current flowing, trips the circuit, and cuts off the electricity?

The device that senses the current flowing, trips the circuit, and cuts off the electricity is known as a Ground Fault Circuit Interrupter (GFCI). A GFCI is specifically designed to prevent electric shock by detecting imbalances in the electrical current. When it senses that the current flowing through the hot wire is not equal to the current returning through the neutral wire—often due to leakage current or a ground fault—it will rapidly disconnect the electrical supply, usually within milliseconds.

This safety feature is crucial in areas where electrical devices are used near water, such as kitchens and bathrooms, because it significantly reduces the risk of electrical hazards. The quick disconnection from the power source provides a vital protective measure against electric shock, making GFCIs essential for safety in homes and commercial buildings.

While devices like fuses and circuit breakers also serve to cut off electricity in fault conditions, they do so based on overload or short circuit scenarios rather than ground faults specifically. Therefore, the GFCI is uniquely qualified for its intended purpose.