Protective Conductors and Bonding Recap

What is the primary function of a circuit protective conductor (CPC)?

• To carry normal operating current

• To balance voltage in circuits

• To provide a return path for fault current

• To stabilise the voltage of the installation

What does the term "main protective bonding" refer to in BS 7671?

• Bonding between neutral and live conductors

• Bonding between all lighting circuits

• Bonding of extraneous-conductive parts to the main earthing terminal

• Bonding of final circuits to the consumer unit

Which table in BS 7671 is typically used to size main protective bonding conductors?

• Table 4D5

• Table 54.1

• Table 54.7

• Table 4E4A

In a TN-C-S (PME) system, the bonding conductor size is based on:

• Size of the main switch

• Size of the earth electrode

• Supply neutral conductor size

• Size of the RCD

Which of the following is considered an extraneous-conductive part?

• A lighting circuit cable

• An incoming water pipe

• An oven casing

• A trunking lid

Why must protective bonding conductors be connected to pipework close to the point of entry?

• To avoid interference with internal wiring

• To reduce material costs

• To minimise voltage potential differences during faults

• To maintain symmetry in the installation

Which of the following is NOT a function of a CPC?

• Provide a path for fault current

• Maintain safety under fault conditions

• Carry current under normal operation

• Enable disconnection of supply

In TT systems, what device is primarily relied upon for disconnection of supply under earth fault conditions?

• MCB

• RCD

• Main fuse

• Surge protector

What is the minimum CPC size allowed when using 6 mm² line conductors (referencing Table 54.7)?

• 1.0 mm²

• 2.5 mm²

• 4.0 mm²

• 6.0 mm²

Which regulation in BS 7671 covers the requirements for protective bonding conductors?

• 411.3.1.1

• 522.6.202

• 544.1.1

• 433.1.1