Earthing systems

What is the purpose of Part 3 of BS 7671?

• To outline safety procedures

• To assess general characteristics of electrical installations

• To specify wiring regulations

• To define maximum demand criteria

Which chapter of BS 7671 deals with supply characteristics?

• Chapter 5

• Chapter 31

• Chapter 54

• Chapter 12

What is the key consideration in Section 311 of BS 7671?

• Maximum demand assessment

• Conductor arrangements

• Earthing arrangements

• Diversity assessment

Which conductor arrangement is typically used for construction site supplies?

• Single-phase two-wire

• Three-phase four-wire

• Two-phase three-wire

• Four-phase five-wire

In TN-C-S earthing arrangements, what does PEN stand for?

• Protective earth-neutral

• Protective earthing network

• Protective earthed neutral

• Protective neutral-earth

What risk is associated with PME systems if an open circuit occurs in the supply PEN?

• Overloading of circuits

• Corrosion of conductors

• Diverted neutral currents

• Short circuits

Why are main equipotential bonding conductors larger in PME systems?

• To reduce resistance

• To prevent corrosion

• To handle diverted neutral currents

• To improve insulation

In which scenario might a DNO refuse to provide a PME supply?

• Residential buildings

• Construction sites

• Industrial factories

• Commercial offices

Which earthing system uses the lead sheath of the cable as the protective conductor?

• TN-C-S

• TN-S

• TT

• TN-C

What is the primary reason for converting TN-S distribution systems to TN-C-S?

• Cost savings

• Improved safety

• Increased efficiency

• Regulatory compliance