Earthing and Bonding Flashcards
6 cards from real ECS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Earthing and Bonding flashcards as text
What is a 'supplementary bonding conductor' and when is it typically required?
Answer: A conductor connecting simultaneously accessible conductive parts in locations such as bathrooms where shock risk is higher
Supplementary bonding connects simultaneously accessible conductive parts (e.g., metallic bath, pipes, and radiator in a bathroom) to minimize potential differences in high-risk locations.
What does the term 'earth fault loop impedance' (Zs) represent?
Answer: The total impedance of the complete fault current path from the source, through the circuit, to earth and back
Earth fault loop impedance (Zs) is the total impedance of the path a fault current follows, which determines how quickly the protective device will operate under fault conditions.
An RCD (Residual Current Device) provides additional protection — what fault condition does it detect?
Answer: An imbalance between live and neutral currents indicating current leaking to earth
An RCD monitors the difference between live and neutral currents; if current leaks to earth (through a person or fault), this imbalance triggers rapid disconnection.
Where must the main earthing terminal (MET) be located in a typical installation?
Answer: As close as practicable to the supply intake, with all earth conductors connected to it
The main earthing terminal is the central hub for all earthing and bonding conductors and should be located near the supply intake to minimize impedance in the earth fault loop.
What is an 'earth electrode' and what is its purpose?
Answer: A conductive element such as a ground rod driven into the earth to provide a connection to the general mass of earth
An earth electrode (typically a copper-clad steel rod driven into the ground) provides a low-resistance connection to the general mass of earth for fault current dissipation.
What test is carried out to verify the effectiveness of an earth electrode?
Answer: Earth electrode resistance test using a specialized earth tester with auxiliary test spikes
Earth electrode resistance is measured using a dedicated earth tester with auxiliary current and potential spikes driven into the ground at set distances from the electrode.