Quiz on Earthing and Bonding

What is the primary purpose of earthing in electrical installations?

• To provide a path for fault current to flow to earth

• To stabilize the voltage

• To increase the electrical resistance

• To generate electrical power

What does bonding aim to reduce in an electrical installation?

• Cost of materials

• Risk of electric shock

• Energy consumption

• Circuit complexity

Which document covers the safety requirements for earthing and bonding?

• BS7671

• ISO 9001

• NEC 240

• IEEE 802

What is a TN-S earthing system characterized by?

• A combined neutral and earth connection

• A single neutral-to-earth connection near the supply transformer

• Multiple earth connections throughout the installation

• Use of the earth as a conductor

What is the maximum external earth fault loop impedance in a TN-C-S system?

• 0.8 Ω

• 0.35 Ω

• 0.5 Ω

• 1.0 Ω

Which system is most commonly used in the UK and known as protective multiple earthing?

• TN-S

• TT

• IT

• TN-C-S

In which scenario is a TT system typically used?

• In urban areas with high building density

• Where TN-C-S arrangements cannot be used

• In large industrial complexes

• In areas with stable soil types

What does electrical bonding connect?

• All insulated cables

• All live metallic items

• All plastic components

• All exposed metallic items not designed to carry electricity

What is the ohmic value threshold that determines if a metallic tray needs to be bonded?

• Less than 22 kΩ

• More than 50 kΩ

• Less than 10 kΩ

• More than 100 kΩ

What type of earthing system uses the earth as a conductor to save costs?

• Functional earthing

• TN-C-S

• TT

• TN-S