Fault current flows only when there is a

• A. Complete circuit
• B. Open circuit
• C. Short circuit
• D. Ground connection

Answer: (A)

Current can only flow if there is a closed path back to the source. In a fault situation, the current will only flow if that loop is complete; if the circuit is open, the path is broken and no current passes, even though a fault exists. A short circuit is a fault with very low resistance, which can cause a large current, but it still requires a closed loop to deliver that current. A ground connection isn’t required for fault current to flow—some faults do travel through the earth, but many faults occur entirely within the circuit path. So the essential condition for fault current to occur is a complete circuit.