*Question T0A08:
Where should a fuse or circuit breaker be installed in a 120V AC power circuit?*  

*Correct Answer is  A: In series with the hot conductor only*  

### AI Response: (may contain errors)  

To determine where a fuse or circuit breaker should be installed in a 120V AC power circuit, we need to understand the purpose of these protective devices.

### Correct Answer: A - In series with the hot conductor only

- **Reasoning**: 
  - A fuse or circuit breaker is designed to interrupt the flow of current in the event of an overload or short circuit. 
  - By placing it in series with the hot conductor, it ensures that if there is a fault, the current will be cut off, preventing potential hazards such as electrical fires or equipment damage.
  - The neutral conductor is not switched because it is typically at ground potential, and interrupting it could create a shock hazard.

### Why the Other Choices are Incorrect:

- **B: In series with the hot and neutral conductors**:
  - This configuration is not ideal because it can create a situation where the circuit is not properly grounded. If the neutral is interrupted, devices may still be energized, posing a shock risk.

- **C: In parallel with the hot conductor only**:
  - A fuse or circuit breaker in parallel would not effectively interrupt the current flow. Instead, it would allow current to bypass the protection device, rendering it useless in the event of a fault.

- **D: In parallel with the hot and neutral conductors**:
  - Similar to option C, placing a fuse or circuit breaker in parallel would not provide protection. It would allow current to flow around the device, failing to interrupt the circuit during an overload or short circuit.

### Summary:
- Always install fuses or circuit breakers in series with the hot conductor to ensure effective protection against overloads and short circuits.
- This setup ensures that the entire circuit is de-energized in case of a fault, enhancing safety.

### Rule of Thumb:
- **Always ensure that protective devices are installed in a manner that they can effectively interrupt the current flow in the event of a fault.**