EMC Question of the Week: April 4, 2022
Ground fault circuit interrupters (GFCIs) interrupt the connection to the power source when they detect a
- significant current flowing on the ground conductor
- significant difference in the currents flowing on the two power conductors
- loss of the connection to one or both power conductors
- power current surge
Answer
The best answer is “b.” All GFCIs are triggered by detecting a difference in the currents flowing on the two power conductors. Most GFCIs found in homes trip when the difference is about 6 mA.
Unlike a fuse or standard circuit breaker, a GFCI removes the connection to both the power and power-return wires. It is not necessary for a product to have a ground conductor in order to utilize a GFCI. A growing number of products that operate at voltages greater than about 50 Vrms utilize built-in GFCI circuitry.
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