Journeyman Electrician Practice Exam

What must accessible non-current-carrying metal parts of a central vacuum assembly be connected to if likely to be energized?

1. A circuit breaker

2. Grounded conductor

3. An equipment grounding conductor

4. Power supply

The correct answer is: An equipment grounding conductor

The requirement for accessible non-current-carrying metal parts of a central vacuum assembly to be connected to an equipment grounding conductor ensures safety by providing a path for any fault current. In the event that these metal parts become energized due to a fault, connecting them to an equipment grounding conductor helps to minimize the risk of electric shock to users and facilitates the operation of overcurrent protective devices, such as circuit breakers, to trip and disconnect the circuit. An equipment grounding conductor is specifically designed for this purpose, as it is intended to carry fault current safely to ground. This preventive measure is critical in systems where both electrical safety and equipment protection are priorities. It ensures that these metal parts remain at ground potential during normal operation and that any fault condition is quickly addressed. While other choices involve important components in electrical safety and circuit functionality, they do not fulfill the specific requirement for grounding metallic parts in this context. For example, a circuit breaker protects circuits but does not serve as a grounding path. Similarly, a grounded conductor carries current as part of an electrical circuit and is not intended for grounding non-current-carrying parts. Power supply, while essential for operation, likewise does not provide the necessary grounding connection. Thus, connecting the metal parts to an equipment grounding conductor is