BS 7671 18 Edition Part 8 and Appendices practice questions

What is the disconnection time if a current of 300 A occurs in a circuit protected by 45 A fuse to BS 88-3?

• 5 s

• 1 s

• 0.4 s

• 0.2 s

Answer explanation

Fig 3A1

What correction factor should be applied when determining conductor sizes where cables are buried direct in the ground?

• 0.725

• 0.8

• 0.9

• 1.2

Answer explanation

Appendix 4 Section 4

The external influence code relating to impact is which of the following?

• AA

• AC

• AE

• AG

Answer explanation

Appendix 5

An approximation of the simultaneous short-circuit fault current between all live conductors is given by multiplying the prospective fault current measured between line and neutral by which of the following?

• √3

• 1.414

• 2

• 3

Answer explanation

Appendix 14

What is the maximum number of twin socket-outlets that may be connected to a ring final circuit via an unfused spur?

• 1

• 2

• Number is dependent upon the load characteristics taking diversity into account

• Unlimited

Answer explanation

Appendix 15

Which of the following is NOT a type of prosumer’s electrical installation (PEI) recognized by Chapter 82?

• Individual PEI

• Mutual PEI

• Collective PEI

• Shared PEI

Answer explanation

824.1

When a PEI is operating in reverse feeding mode, it may supply energy to:

• Loads within the premises

• The storage units at the premises

• The public network

• All of the above

Answer explanation

Annex B82

The diagram below illustrates the layout of which of the following PEI systems?

• Collective PEI utilizing the DNO distribution system

• Shared PEI utilizing the DNO distribution system

• Collective PEI utilizing an internal distribution system

• Shared PEI utilizing an internal distribution system

Answer explanation

824.4