Electrician's Licensing Practice Exam

What is a common application for high impedance grounding?

1. Residential grounding

2. Grounding radio towers

3. Grounding industrial machinery

4. Grounding in dry areas

The correct answer is: Grounding radio towers

High impedance grounding is primarily used in settings where it is critical to limit fault currents while still providing a path for ground fault current to return to the source. This method is widely adopted in systems such as those used for grounding radio towers. Radio towers are often situated in remote or isolated areas and are subjected to high levels of electromagnetic interference and lightning strikes. High impedance grounding minimizes the risk of damage by allowing only a small amount of fault current to flow, which effectively protects the sensitive equipment associated with radio transmission. This approach can prevent operational interruptions while maintaining safety standards. In contrast, residential grounding typically employs more standard grounding practices aimed at protecting household appliances and ensuring safety. Grounding industrial machinery and grounding in dry areas would not necessitate the specific characteristics provided by high impedance grounding, as these applications typically require a more robust grounding strategy to manage higher fault currents effectively.