*Question G0B05:
Which of the following conditions will cause a ground fault circuit interrupter (GFCI) to disconnect AC power?*  

*Correct Answer is  B: Current flowing from one or more of the hot wires directly to ground*  

### AI Response: (may contain errors)  

A Ground Fault Circuit Interrupter (GFCI) is designed to protect people from electric shock by detecting ground faults. Here's how it works and why the correct answer is B:

1. **Correct Answer: B - Current flowing from one or more of the hot wires directly to ground**

   - A GFCI monitors the current balance between the hot wire(s) and the neutral wire. Under normal conditions, the current flowing to the load through the hot wire should return through the neutral wire.
   - If there is a ground fault, some of the current flows directly to the ground instead of returning through the neutral wire. This creates an imbalance.
   - The GFCI detects this imbalance and disconnects the power if the difference exceeds a certain threshold (typically 5 mA), preventing potential electric shock.

2. **Why the Other Choices are Incorrect:**

   - **A: Current flowing from one or more of the hot wires to the neutral wire**
     - This is normal operation. The GFCI expects the current to flow from the hot wire to the neutral wire. It only trips when there is an imbalance, indicating a ground fault.
   
   - **C: Overvoltage on the hot wires**
     - GFCIs are not designed to detect overvoltage conditions. Overvoltage protection is typically handled by surge protectors or circuit breakers, not GFCIs.
   
   - **D: All these choices are correct**
     - Since A and C are incorrect, D cannot be correct. The GFCI specifically trips due to ground faults, not normal current flow or overvoltage.

3. **Useful Rule of Thumb:**

   - A GFCI trips when there is a current imbalance between the hot and neutral wires, indicating that some current is leaking to ground. This is a key safety feature to prevent electric shock.