Exposed, Extraneous Conductive Parts.... Earthing vs Bonding

What is the purpose of a protective earthing conductor?

• To limit the duration of a fault to allow a protective device to operate

• To connect extraneous conductive parts of the installation

• To increase the electrical resistance of the installation

• To provide a path for normal operation current

Which of the following is an example of an exposed conductive part?

• Copper water pipe

• Metal switch covers

• Metallic gas pipe

• Steel sink

What is the main purpose of protective bonding?

• To prevent overvoltage

• To reduce energy consumption

• To limit the size of the fault by equalising potential

• To isolate the electrical installation

What does equipotential bonding aim to achieve?

• Decrease the conductivity of metal parts

• Increase the potential difference

• Prevent electrical devices from operating

• Make all metalwork at the same potential as earth

Which of the following is considered an extraneous conductive part?

• Appliance cases

• Steel trunking

• Copper water pipe

• Metal switch covers

What happens under fault conditions without proper bonding?

• A serious shock could result because of the difference in potential

• All metalwork rises to the same potential

• There is no potential difference across metalwork

• The fault current is immediately interrupted

What is connected to the MET (main earthing terminal)?

• Neither protective earthing nor bonding conductors

• Both protective earthing and bonding conductors

• Bonding conductors only

• Protective earthing conductor only

Why do we bond extraneous conductive parts of an installation?

• To increase the electrical load capacity

• To limit the size of the fault by equalising potential

• To allow for easier installation

• To reduce the cost of electrical maintenance

What is the result of all metalwork being at the same potential?

• Increased potential difference

• No dangerous shock current

• Decreased efficiency of protective devices

• Higher electrical resistance

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

• To limit the duration of a fault to allow a protective device to operate

• To increase the potential difference under fault conditions

• To carry the operational current

• To connect extraneous conductive parts