This 18th Edition practice simulator contains 60 Questions. You have 120 minutes (2 hours) to complete the assessment. You must get a score of 36/60 to pass. Good luck!
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1. When performing an initial verification of a new electrical installation, which of the following does not need to be verified?
Mark one answer
B
C
D
Correct Answer: D
Explanation: Page 230 & 231 - 642.3 - The part 6 contents page (P228) indicates chapter 64 refers to 'Initial Verification' you need the realise Initial Verification and Inspection is the main theme of this question, then it is simply a matter of browsing the page, you will find the answer in 642.3
Explanation: Page 230 & 231 - 642.3 - The part 6 contents page (P228) indicates chapter 64 refers to 'Initial Verification' you need the realise Initial Verification and Inspection is the main theme of this question, then it is simply a matter of browsing the page, you will find the answer in 642.3
Correct Answer: D
Explanation: Page 235 - 643.9 - The part 6 contents page (P228) indicates section 643.9 refers to 'Check of phase sequencing' you will find 643.9 on page 235 which advises all polyphase circuits shall be verified for phase sequence. Polyphase means more than one phase, so a three-phase system is a polyphase system
Explanation: Page 235 - 643.9 - The part 6 contents page (P228) indicates section 643.9 refers to 'Check of phase sequencing' you will find 643.9 on page 235 which advises all polyphase circuits shall be verified for phase sequence. Polyphase means more than one phase, so a three-phase system is a polyphase system
Correct Answer: D
Explanation: Page 276 - 710.411.6.3.1 (ii) - The part 7 contents page (P239) indicates section 710 refers to 'Medical locations' Section 710 starts on page 275, you need to look for some reference to IT systems and in 710.411.6.3.1 (ii) (P276) you will find the answer, insulation monitoring devices must have a 'yellow' signal lamp to indicate when the insulation resistance falls to its minimum value
Explanation: Page 276 - 710.411.6.3.1 (ii) - The part 7 contents page (P239) indicates section 710 refers to 'Medical locations' Section 710 starts on page 275, you need to look for some reference to IT systems and in 710.411.6.3.1 (ii) (P276) you will find the answer, insulation monitoring devices must have a 'yellow' signal lamp to indicate when the insulation resistance falls to its minimum value
B
C
D
Correct Answer: C
Explanation: Page 313 - Table A721 - Annex A721 - Linked with A721.55.2.6 - The part 7 contents page (P239) indicates section 721 refers to 'Electrical Installations in Caravans and Motor Caravans' you will find section 721 on page 306, you must skim through the section to Annex A721 to find the answer to this question. Looking for any reference to 'conductor cross-sectional area', you will find this in Table A721 (P313) looking down the table for 'Power supply controlled by ignition switch' and cross-reference with the minimum c.s.a column you will find the answer is 2.5 mm²
Explanation: Page 313 - Table A721 - Annex A721 - Linked with A721.55.2.6 - The part 7 contents page (P239) indicates section 721 refers to 'Electrical Installations in Caravans and Motor Caravans' you will find section 721 on page 306, you must skim through the section to Annex A721 to find the answer to this question. Looking for any reference to 'conductor cross-sectional area', you will find this in Table A721 (P313) looking down the table for 'Power supply controlled by ignition switch' and cross-reference with the minimum c.s.a column you will find the answer is 2.5 mm²
B
C
D
Correct Answer: A
Explanation: Page 259 - 705.415.2.1 Note: - The part 7 contents page (P239) indicates section 705 refers to 'Agricultural and Horticultural Premises' Turning to section 705 (P258) you need to be looking for something to do with 'earthing' Regulation 705.415.2.1 refers to 'Supplementary equipotential bonding' this is a form of earthing so let's look here. The answer is in the Note of 705.415.2.1 'a metal grid laid in the floor is recommended'
Explanation: Page 259 - 705.415.2.1 Note: - The part 7 contents page (P239) indicates section 705 refers to 'Agricultural and Horticultural Premises' Turning to section 705 (P258) you need to be looking for something to do with 'earthing' Regulation 705.415.2.1 refers to 'Supplementary equipotential bonding' this is a form of earthing so let's look here. The answer is in the Note of 705.415.2.1 'a metal grid laid in the floor is recommended'
6. Socket-outlets for use as electric vehicle charging points shall be mounted no lower to the ground than?
Mark one answer
B
C
D
Correct Answer: D
Explanation: Page 318 - 722.55.101.5 - The part 7 contents page (P239) indicates section 722 refers to 'Electric vehicle charging installations' you will find section 722 on page 316, you must look for some reference to 'Socket-outlets' and in 722.55.101.5 (P318) you will find the answer 0.5 m is the minimum height above ground for a vehicle socket-outlet charging point
Explanation: Page 318 - 722.55.101.5 - The part 7 contents page (P239) indicates section 722 refers to 'Electric vehicle charging installations' you will find section 722 on page 316, you must look for some reference to 'Socket-outlets' and in 722.55.101.5 (P318) you will find the answer 0.5 m is the minimum height above ground for a vehicle socket-outlet charging point
7. The nominal single-phase supply voltage for installations supplying houseboats or pleasure craft is?
Mark one answer
B
C
D
Correct Answer: B
Explanation: Page 270 - 709.313.1.2 - The part 7 contents page (P239) indicates section 709 refers to 'Marinas and similar locations' Section 709 starts on page 270, you need to look for some reference to 'Supplies' and in 709.313.1.2 you will find the answer 230 V a.c for single-phase
Explanation: Page 270 - 709.313.1.2 - The part 7 contents page (P239) indicates section 709 refers to 'Marinas and similar locations' Section 709 starts on page 270, you need to look for some reference to 'Supplies' and in 709.313.1.2 you will find the answer 230 V a.c for single-phase
Correct Answer: C
Explanation: Page 240 - 701.32.2 - The part 7 contents page (P239) indicates section 701 refers to 'Locations containing a bath or shower' you will find section 701 on page 240, and 701.32.2 contains the description for zone 0 i.e. for showers without a basin zone 0 extends to a vertical height of 0.1 m
Explanation: Page 240 - 701.32.2 - The part 7 contents page (P239) indicates section 701 refers to 'Locations containing a bath or shower' you will find section 701 on page 240, and 701.32.2 contains the description for zone 0 i.e. for showers without a basin zone 0 extends to a vertical height of 0.1 m
9. Electrical equipment at a travelling fairground needs inspecting and testing after each assembly on site except?
Mark one answer
B
C
D
Correct Answer: D
Explanation: Page 334 - 740.6 Note 1: - The part 7 contents page (P239) indicates section 740 refers to 'Travelling fairgrounds' you will find this section on page 330, you need to skim through this section looking for any reference to 'Inspection and testing' you will find the answer on page 334 in section 740.6 the internal wiring of dodgems are not part of the inspection & test
Explanation: Page 334 - 740.6 Note 1: - The part 7 contents page (P239) indicates section 740 refers to 'Travelling fairgrounds' you will find this section on page 330, you need to skim through this section looking for any reference to 'Inspection and testing' you will find the answer on page 334 in section 740.6 the internal wiring of dodgems are not part of the inspection & test
B
C
D
Correct Answer: D
Explanation: Page 256 - 704.1.1 - The part 7 contents page (P239) indicates section 704 refers to 'Construction and Demolition Site Installations' you will find section 704 on page 256 the answer to these types of questions i.e. 'what is covered, what is not covered' are usually found in the 'Scope' parts of a section. you will find 704.1.1 states what is covered by construction site regulations, the last paragraph states what is NOT covered e.g. site offices
Explanation: Page 256 - 704.1.1 - The part 7 contents page (P239) indicates section 704 refers to 'Construction and Demolition Site Installations' you will find section 704 on page 256 the answer to these types of questions i.e. 'what is covered, what is not covered' are usually found in the 'Scope' parts of a section. you will find 704.1.1 states what is covered by construction site regulations, the last paragraph states what is NOT covered e.g. site offices
B
C
D
Correct Answer: C
Explanation: Page 267 - 708.55.1.2 - The part 7 contents page (P239) indicates section 708 refers to 'Electrical installations in caravan and camping parks' 708 starts on page 265; a connection facility for a caravan usually means a socket outlet, so searching for 'socket outlets' you will find the answer in 708.55.1.2 which states the maximum length is 20 metres
Explanation: Page 267 - 708.55.1.2 - The part 7 contents page (P239) indicates section 708 refers to 'Electrical installations in caravan and camping parks' 708 starts on page 265; a connection facility for a caravan usually means a socket outlet, so searching for 'socket outlets' you will find the answer in 708.55.1.2 which states the maximum length is 20 metres
12. Electrical equipment installed in the basin of a fountain shall have a degree of protection of at least?
Mark one answer
B
C
D
Correct Answer: C
Explanation: Page 247 - 702.512.2 (i) - The part 7 contents page (P239) indicates section 702 refers to 'Swimming pools and other basins' you will find section 702 on page 245, you should know the basin of a fountain is in zone 0, if you didn't you do now. 'Degree of protection' often refers to 'External influences' so searching for external influences you will find the answer in 702.512.2 (i) (P247) When electrical equipment is installed in the basin of a fountain (i.e. zone 0) then ingress protection to IPX8 is required
Explanation: Page 247 - 702.512.2 (i) - The part 7 contents page (P239) indicates section 702 refers to 'Swimming pools and other basins' you will find section 702 on page 245, you should know the basin of a fountain is in zone 0, if you didn't you do now. 'Degree of protection' often refers to 'External influences' so searching for external influences you will find the answer in 702.512.2 (i) (P247) When electrical equipment is installed in the basin of a fountain (i.e. zone 0) then ingress protection to IPX8 is required
Correct Answer: B
Explanation: Page 340 - The Appendix contents page (P339) indicates Appendix 1 refers to 'British Standards' Appendix 1 starts on page 340, browsing through the standards to BS 88-2-2 you will find this relates to low-voltage fuses, you should know these are cartridge fuses
Explanation: Page 340 - The Appendix contents page (P339) indicates Appendix 1 refers to 'British Standards' Appendix 1 starts on page 340, browsing through the standards to BS 88-2-2 you will find this relates to low-voltage fuses, you should know these are cartridge fuses
B
C
D
Correct Answer: C
Explanation: Page 363 - Table 3A - The Appendix contents page (P339) indicates Appendix 3 refers to 'Time Current characteristics of overcurrent protective devices and RCDs' Appendix 3 starts on page 362. Any questions of this type will always refer to Table 3A, browsing to Table 3A (P363) you need to cross-reference the Delay S row values with the Rated residual operating current IΔn for a 500 mA RCD (bottom row) Then move along the row until you find the residual current column that is twice the original current: e.g. 2 x 500 mA = 1000 mA, we then find in the 'Trip time' column the maximum value is 200 ms. Don't confuse the 60 min and 200 max values to mean minutes, these values are in milli-seconds (ms)
Explanation: Page 363 - Table 3A - The Appendix contents page (P339) indicates Appendix 3 refers to 'Time Current characteristics of overcurrent protective devices and RCDs' Appendix 3 starts on page 362. Any questions of this type will always refer to Table 3A, browsing to Table 3A (P363) you need to cross-reference the Delay S row values with the Rated residual operating current IΔn for a 500 mA RCD (bottom row) Then move along the row until you find the residual current column that is twice the original current: e.g. 2 x 500 mA = 1000 mA, we then find in the 'Trip time' column the maximum value is 200 ms. Don't confuse the 60 min and 200 max values to mean minutes, these values are in milli-seconds (ms)
15. What is the current required to operate a 6A BS EN 60898 Type C MCB between 0.1 and 5 seconds?
Mark one answer
B
C
D
Correct Answer: D
Explanation: Page 371 - Fig 3A5 - Type C circuit-breakers to BS EN 60898 - Appendix 3 - The appendices contents page 339 indicates Appendix 3 starts on page 362 refers to 'Time/Current characteristics of overcurrent protective devices and RCD's'. Browsing to (P362) we look through the section for Type C circuit breakers which you will find in Fig 3A5 (P371). We just need to look in the box in the top right-hand side of the page, and you will see a 6-amp circuit breaker will break between 0.1 to 5 seconds when 60 amps of current flow through it
Explanation: Page 371 - Fig 3A5 - Type C circuit-breakers to BS EN 60898 - Appendix 3 - The appendices contents page 339 indicates Appendix 3 starts on page 362 refers to 'Time/Current characteristics of overcurrent protective devices and RCD's'. Browsing to (P362) we look through the section for Type C circuit breakers which you will find in Fig 3A5 (P371). We just need to look in the box in the top right-hand side of the page, and you will see a 6-amp circuit breaker will break between 0.1 to 5 seconds when 60 amps of current flow through it
B
C
D
Correct Answer: B
Explanation: Page 384 - Section 7.2 - The answer to this question is in Appendix 4, but the main Appendix contents page gives no indication of this. You need to remember anything to do with cable installation methods in the Appendix section will probably be in Appendix 4. you will find the answer on page 384 section 7.2 'Other installation methods' where we are advised cables under a ceiling must use installation reference method B. If you didn't know this section was here, well you do now
Explanation: Page 384 - Section 7.2 - The answer to this question is in Appendix 4, but the main Appendix contents page gives no indication of this. You need to remember anything to do with cable installation methods in the Appendix section will probably be in Appendix 4. you will find the answer on page 384 section 7.2 'Other installation methods' where we are advised cables under a ceiling must use installation reference method B. If you didn't know this section was here, well you do now
Correct Answer: B
Explanation: Page 400 - Table 4C6 - The Appendix contents page (P339) indicates Appendix 4 refers to 'Current-carrying capacity of cables' Appendix 4 starts on page 373, the Appendix 4 contents page (P373) indicates Table 4C6 refers to 'Rating factors for cables enclosed in infloor concrete troughs' you will find Table 4C6 on (P400) you will find there are two options for 'six-single core cables' e.g. Installation method 118 (column 5) and installation method 119 (column 6) so you need to first determine which installation method applies. We turn to page 391 - Table 4A2 'Installation methods for cables enclosed in infloor concrete troughs' and you will find the dimensions given in the question e.g. '450 mm wide by 600 mm deep with a 100 mm cover' can only refer to installation method 119. So, we now go back to page 400 - Table 4C6. We now cross-reference the 6 mm² cable row with 6 single-core cables under the installation method 119 (column 6) and find the answer is a derating factor of 0.86
Explanation: Page 400 - Table 4C6 - The Appendix contents page (P339) indicates Appendix 4 refers to 'Current-carrying capacity of cables' Appendix 4 starts on page 373, the Appendix 4 contents page (P373) indicates Table 4C6 refers to 'Rating factors for cables enclosed in infloor concrete troughs' you will find Table 4C6 on (P400) you will find there are two options for 'six-single core cables' e.g. Installation method 118 (column 5) and installation method 119 (column 6) so you need to first determine which installation method applies. We turn to page 391 - Table 4A2 'Installation methods for cables enclosed in infloor concrete troughs' and you will find the dimensions given in the question e.g. '450 mm wide by 600 mm deep with a 100 mm cover' can only refer to installation method 119. So, we now go back to page 400 - Table 4C6. We now cross-reference the 6 mm² cable row with 6 single-core cables under the installation method 119 (column 6) and find the answer is a derating factor of 0.86
Correct Answer: C
Explanation: Page 91 - 434.1 - The part 4 contents page (P53) indicates section 434 refers to 'Protection against fault current'. You could have also used the chapter 43 contents page (P86) here you will find section 434.1 refers to 'Determination of prospective fault current' This points to where we will find the answer. Turning to page 91 - 434.1 you will find the answer
Explanation: Page 91 - 434.1 - The part 4 contents page (P53) indicates section 434 refers to 'Protection against fault current'. You could have also used the chapter 43 contents page (P86) here you will find section 434.1 refers to 'Determination of prospective fault current' This points to where we will find the answer. Turning to page 91 - 434.1 you will find the answer
19. The most commonly used protective measure to provide protection against electric shock, in an electrical installation is?
Mark one answer
B
C
D
Correct Answer: A
Explanation: Page 56 - 410.3.3 Note: - The part 4 contents page (P53) indicates Sections 411, 412, 413, and 414 refer to protective measures. You could spend a lot of time browsing these sections looking for the correct answer; however, 410.3.3 Note: at the bottom of page 56 states ADS is the most common form of protection in electrical installations. If this question comes up in your exam you now know where to find the answer
Explanation: Page 56 - 410.3.3 Note: - The part 4 contents page (P53) indicates Sections 411, 412, 413, and 414 refer to protective measures. You could spend a lot of time browsing these sections looking for the correct answer; however, 410.3.3 Note: at the bottom of page 56 states ADS is the most common form of protection in electrical installations. If this question comes up in your exam you now know where to find the answer
Correct Answer: C
Explanation: Page 81 - 422.2 - The part 4 contents page (P53) indicates section 422 refers to 'Precautions where particular risks of fire exist' this is not much use to you if you don't realise the relationship between the contents and the question. You need to remember section 422 refers to precautions where particular risks of fire exist. You could also try the appendices contents page (P339) here you will find external influences start on (P445) on page (P446) you will find BD3 refers to crowded evacuation, but the evacuation is not normal or difficult so it must be crowded and easy
Explanation: Page 81 - 422.2 - The part 4 contents page (P53) indicates section 422 refers to 'Precautions where particular risks of fire exist' this is not much use to you if you don't realise the relationship between the contents and the question. You need to remember section 422 refers to precautions where particular risks of fire exist. You could also try the appendices contents page (P339) here you will find external influences start on (P445) on page (P446) you will find BD3 refers to crowded evacuation, but the evacuation is not normal or difficult so it must be crowded and easy
Correct Answer: D
Explanation: Page 98 - Table 44.1 - The part 4 contents page (P53) indicates section 442 refers to 'Protection of low voltage installations against temporary overvoltages due to earth faults' you need to remember this section and Table 44.1 are used to answer this type of question. In Table 44.1, we cross-reference the row with IT systems RE and RA interconnected, with the U1 column; you will find the answer is U0 x √3 At the bottom of the table the symbol † (looks like a dagger) we are informed applies to circuits 'With existing earth faults'
Explanation: Page 98 - Table 44.1 - The part 4 contents page (P53) indicates section 442 refers to 'Protection of low voltage installations against temporary overvoltages due to earth faults' you need to remember this section and Table 44.1 are used to answer this type of question. In Table 44.1, we cross-reference the row with IT systems RE and RA interconnected, with the U1 column; you will find the answer is U0 x √3 At the bottom of the table the symbol † (looks like a dagger) we are informed applies to circuits 'With existing earth faults'
Correct Answer: D
Explanation: Page 58 - 411.3.1.2 - The part 4 contents page provides no guidance to answering this question, but the index does (P536) advises an 'extraneous conductive part - bonding of' is referred to in regulation 411.3.1.2 and on page (P58) you will find the answer, PVC conduit is not an extraneous conductive part
Explanation: Page 58 - 411.3.1.2 - The part 4 contents page provides no guidance to answering this question, but the index does (P536) advises an 'extraneous conductive part - bonding of' is referred to in regulation 411.3.1.2 and on page (P58) you will find the answer, PVC conduit is not an extraneous conductive part
Correct Answer: D
Explanation: Page 57 - 410.3.9 (v) - This is not an easy answer to find, the part 4 contents page does not point to an answer, so it is to the index you must turn. On Page 537 under 'Fault protection - omission for certain items of equipment' we are directed to 410.3.9 and there in 410.3.9 (v) you will find the answer
Explanation: Page 57 - 410.3.9 (v) - This is not an easy answer to find, the part 4 contents page does not point to an answer, so it is to the index you must turn. On Page 537 under 'Fault protection - omission for certain items of equipment' we are directed to 410.3.9 and there in 410.3.9 (v) you will find the answer
24. What is the minimum cross-sectional area of an unscreened multi-core copper conductor used for data transfer?
Mark one answer
B
C
D
Correct Answer: A
Explanation: Page 216 - Table 55.2 - 557.4.1 - The part 5 contents page (P125) indicates section 557 refers to 'Auxiliary circuits', so you need to remember cables used for 'data transfer' will be in this section. We can make use of the chapter 55 contents page (P204) here you will find section 557.4 refers to 'Characteristics of cables and conductors' associated with auxiliary circuits, and on page 216 - Table 55.2 you will find the answer. It is a simple case of cross-referencing 'data transfer' with Multicore unscreened cables and you will find the answer is 0.1 mm²
Explanation: Page 216 - Table 55.2 - 557.4.1 - The part 5 contents page (P125) indicates section 557 refers to 'Auxiliary circuits', so you need to remember cables used for 'data transfer' will be in this section. We can make use of the chapter 55 contents page (P204) here you will find section 557.4 refers to 'Characteristics of cables and conductors' associated with auxiliary circuits, and on page 216 - Table 55.2 you will find the answer. It is a simple case of cross-referencing 'data transfer' with Multicore unscreened cables and you will find the answer is 0.1 mm²
B
C
D
Correct Answer: B
Explanation: Page 184 - 537.3.3.5 - The part 5 contents page (P124) indicates section 537 refers to 'Isolation and switching' The chapter 53 contents page (P150) advises section 537.4 refers to 'Firefighter's Switches' On page 184, you will find 'Firefighter's switches' but sadly we won't find the answer here. In the 17th Edition Wiring Regulations the answer to this question would have been in this section but not anymore. you will find the answer in section 537.3.3 'Devices for emergency switching off' in regulation 537.3.3.5 you will find if a device is used for emergency switching off, the colour must be Red
Explanation: Page 184 - 537.3.3.5 - The part 5 contents page (P124) indicates section 537 refers to 'Isolation and switching' The chapter 53 contents page (P150) advises section 537.4 refers to 'Firefighter's Switches' On page 184, you will find 'Firefighter's switches' but sadly we won't find the answer here. In the 17th Edition Wiring Regulations the answer to this question would have been in this section but not anymore. you will find the answer in section 537.3.3 'Devices for emergency switching off' in regulation 537.3.3.5 you will find if a device is used for emergency switching off, the colour must be Red
Correct Answer: A
Explanation: Page 219 - 559.5.1 (i) - The part 5 contents page (P125) indicates section 559 refers to 'Luminaires and lighting installations' - you will find section 559 on page 218, skimming the section you will find 559.5.1 (i) on page 219 and the answer
Explanation: Page 219 - 559.5.1 (i) - The part 5 contents page (P125) indicates section 559 refers to 'Luminaires and lighting installations' - you will find section 559 on page 218, skimming the section you will find 559.5.1 (i) on page 219 and the answer
Correct Answer: D
Explanation: Page 206 - 551.1.1 - The part 5 contents page (P124) indicates section 551 refers to 'Low voltage generating sets' - Turning to section 551 (P206) and browsing you will find the answer in 551.1.1, the public mains supply is NOT listed
Explanation: Page 206 - 551.1.1 - The part 5 contents page (P124) indicates section 551 refers to 'Low voltage generating sets' - Turning to section 551 (P206) and browsing you will find the answer in 551.1.1, the public mains supply is NOT listed
28. The presence of a SPD (Surge Protection Device) installed downstream of a distribution board shall be indicated by?
Mark one answer
B
C
D
Correct Answer: A
Explanation: Page 162 - 534.4.1.7 - The part 5 contents page (P124) indicates section 534 refers to 'Devices for protection against overvoltage' you will find the answer in 534.4.1.7 on page 162 warning labels at or near the DB shall indicate the presence of SPDs
Explanation: Page 162 - 534.4.1.7 - The part 5 contents page (P124) indicates section 534 refers to 'Devices for protection against overvoltage' you will find the answer in 534.4.1.7 on page 162 warning labels at or near the DB shall indicate the presence of SPDs
29. A wiring system is installed on a river wall where it may be subject to 'waves' the external influence code is?
Mark one answer
B
C
D
Correct Answer: D
Explanation: Page 138 - 522.3.3 - The part 5 contents page (P124) indicates section 522 refers to the 'Selection and erection of wiring systems in relation to external influences' You need to remember that anything that can damage a wiring system is considered an 'External Influence'. you will find section 522 on page 128 at the bottom of the page you will find 522.3.3 and the answer. We could also have used Appendix 5 (P446) here you will find AD6 listed as 'Waves'
Explanation: Page 138 - 522.3.3 - The part 5 contents page (P124) indicates section 522 refers to the 'Selection and erection of wiring systems in relation to external influences' You need to remember that anything that can damage a wiring system is considered an 'External Influence'. you will find section 522 on page 128 at the bottom of the page you will find 522.3.3 and the answer. We could also have used Appendix 5 (P446) here you will find AD6 listed as 'Waves'
Correct Answer: C
Explanation: Page 199 - 543.2.3 - The part 5 contents page (P124) indicates section 543 refers to 'Protective conductors' we can use the chapter 54 contents page (P193) which indicates section 543.2 refers to 'Types of protective conductors' On page 199, you will find 543.2.1, which lists suitable protective conductors, and you will find 543.2.3 which lists what shall NOT be used. Gas pipe is NOT listed
Explanation: Page 199 - 543.2.3 - The part 5 contents page (P124) indicates section 543 refers to 'Protective conductors' we can use the chapter 54 contents page (P193) which indicates section 543.2 refers to 'Types of protective conductors' On page 199, you will find 543.2.1, which lists suitable protective conductors, and you will find 543.2.3 which lists what shall NOT be used. Gas pipe is NOT listed
31. Which of the following devices would not be suitable for switching of a circuit for maintenance purposes?
Mark one answer
B
C
D
Correct Answer: B
Explanation: Page 181 - Table 537.4 - The part 5 contents page (P124) indicates section 537 refers to 'Isolation and switching' so we will start here. You need to remember Table 537.4 This table lists devices that can be used for Isolation, Emergency, and Functional switching. you need to look down the Device column and cross-reference the devices listed in the answer options with the Functional switching column. Remember functional switching simply means being able to switch something off and on. you will find that options are all suitable for functional switching (e.g. switching off a circuit) but fuses to BS 88 are NOT
Explanation: Page 181 - Table 537.4 - The part 5 contents page (P124) indicates section 537 refers to 'Isolation and switching' so we will start here. You need to remember Table 537.4 This table lists devices that can be used for Isolation, Emergency, and Functional switching. you need to look down the Device column and cross-reference the devices listed in the answer options with the Functional switching column. Remember functional switching simply means being able to switch something off and on. you will find that options are all suitable for functional switching (e.g. switching off a circuit) but fuses to BS 88 are NOT
Correct Answer: A
Explanation: Page 224 - 560.6.2 - The part 5 contents page (P125) indicates section 560.6 refers to 'Electrical sources for safety services'; turning to section 560.6 (P224) a quick skim down the page reveals 560.6.2 and the answer
Explanation: Page 224 - 560.6.2 - The part 5 contents page (P125) indicates section 560.6 refers to 'Electrical sources for safety services'; turning to section 560.6 (P224) a quick skim down the page reveals 560.6.2 and the answer
Correct Answer: C
Explanation: Page 129 - 514.1.2 - The part 5 contents page (P124) indicates section 514 refers to 'Identification and notices' - Turning to this section, towards the top of page 129, you will find 514.1.2 and the answer
Explanation: Page 129 - 514.1.2 - The part 5 contents page (P124) indicates section 514 refers to 'Identification and notices' - Turning to this section, towards the top of page 129, you will find 514.1.2 and the answer
34. A semi-enclosed fuse has blown. The fuse is rated at 30A, what sise wire should be used to repair the fuse?
Mark one answer
B
C
D
Correct Answer: B
Explanation: Page 159 - Table 533.1 - 533.1.2.3 - The part 5 contents page is not much use in helping to find the answer to this question. If you know BS 7671 well enough, you may know the chapter 53 contents page is on (P150) here you will find directions to section 533.1.2 which refers to 'Fuses' so let's look here. On (P159) you will find Table 533.1 which lists the size of tinned copper wire for use as fuse elements. you will find for a 30 amp fuse the fuse wire should be 0.85mm diameter
Explanation: Page 159 - Table 533.1 - 533.1.2.3 - The part 5 contents page is not much use in helping to find the answer to this question. If you know BS 7671 well enough, you may know the chapter 53 contents page is on (P150) here you will find directions to section 533.1.2 which refers to 'Fuses' so let's look here. On (P159) you will find Table 533.1 which lists the size of tinned copper wire for use as fuse elements. you will find for a 30 amp fuse the fuse wire should be 0.85mm diameter
Correct Answer: D
Explanation: Page 146 - 526.9.1 - The part 5 contents page (P124) indicates section 526 refers to 'Electrical connections' so start here. Page 146 - 526.9.1 provides the answer, you must use suitable ferules on the ends of the conductors. Regulation 526.9.2 advises soldering the ends of fine multi-wire conductors is NOT permitted if screw terminals are used. The reason is not stated in BS 7671 but presumably it has to do with the heat from a soldering iron damaging the cable insulation, or possibly the pressure from the screw terminal compressing the solder layer and over time leading to a loose connection
Explanation: Page 146 - 526.9.1 - The part 5 contents page (P124) indicates section 526 refers to 'Electrical connections' so start here. Page 146 - 526.9.1 provides the answer, you must use suitable ferules on the ends of the conductors. Regulation 526.9.2 advises soldering the ends of fine multi-wire conductors is NOT permitted if screw terminals are used. The reason is not stated in BS 7671 but presumably it has to do with the heat from a soldering iron damaging the cable insulation, or possibly the pressure from the screw terminal compressing the solder layer and over time leading to a loose connection
36. When selecting an a.c. wiring system, which one of these cable types shall NOT be used?
Mark one answer
B
C
D
Correct Answer: C
Explanation: Page 137 - 521.5.2 - The part 5 contents page (P124) advises section 521 refers to 'Types of wiring system' Turning to section 521 (P136) and browsing we come to 521.5.2 and the answer. Single core steel wired armoured shall not be used for a.c. circuits
Explanation: Page 137 - 521.5.2 - The part 5 contents page (P124) advises section 521 refers to 'Types of wiring system' Turning to section 521 (P136) and browsing we come to 521.5.2 and the answer. Single core steel wired armoured shall not be used for a.c. circuits
B
C
D
Correct Answer: D
Explanation: Page 144 - 524.2.2 - The part 5 contents page (P124) indicates chapter 524 refers to 'Cross-sectional area of conductors' so start here. On page 144 you will find 524.2 'Neutral conductor' browsing down the section you will find 524.2.2 and the answer
Tip: If you didn't know it, harmonic currents are to be avoided, they are caused by an imbalance of phase currents in a three-phase system, and produce what is known as a 'third harmonic'
The image below shows a 3-phase current waveform with each phase carrying five amps. In a balanced system the net result at any instant in time in the neutral conductor is zero volts and zero amps, this means with a balanced load, there will be no current flowing in the neutral conductor. The net result is shown by the light blue line.
A third harmonic is shown in the image below.
In the image above, due to an imbalance in the Red phase (the old colours are being used as they stand out best), a third harmonic current is generated in the neutral conductor. The third harmonic makes three complete waveform cycles in the time it takes the fundamental (Red phase) to make one cycle. This is why it's called a third harmonic. However, now there's no point in time when the sum of all voltage and current waveforms in the neutral conductor are zero, instead we have an alternating current waveform flowing in the neutral conductor. This can be especially dangerous to the electrician who is not expecting the neutral conductor to be carrying any current. The magnitude of the current in the neutral conductor is easily capable of being lethal to the unwary electrician.
Explanation: Page 144 - 524.2.2 - The part 5 contents page (P124) indicates chapter 524 refers to 'Cross-sectional area of conductors' so start here. On page 144 you will find 524.2 'Neutral conductor' browsing down the section you will find 524.2.2 and the answer
Tip: If you didn't know it, harmonic currents are to be avoided, they are caused by an imbalance of phase currents in a three-phase system, and produce what is known as a 'third harmonic'
The image below shows a 3-phase current waveform with each phase carrying five amps. In a balanced system the net result at any instant in time in the neutral conductor is zero volts and zero amps, this means with a balanced load, there will be no current flowing in the neutral conductor. The net result is shown by the light blue line.
A third harmonic is shown in the image below.
In the image above, due to an imbalance in the Red phase (the old colours are being used as they stand out best), a third harmonic current is generated in the neutral conductor. The third harmonic makes three complete waveform cycles in the time it takes the fundamental (Red phase) to make one cycle. This is why it's called a third harmonic. However, now there's no point in time when the sum of all voltage and current waveforms in the neutral conductor are zero, instead we have an alternating current waveform flowing in the neutral conductor. This can be especially dangerous to the electrician who is not expecting the neutral conductor to be carrying any current. The magnitude of the current in the neutral conductor is easily capable of being lethal to the unwary electrician.
38. The frequency of periodic inspection and testing shall be determined by which of the following?
Mark one answer
B
C
D
Correct Answer: C
Explanation: Page 237 - 652.1 - The part 6 contents page (P228) indicates chapter 65 refers to 'Periodic Inspection and Testing - you will find 'Frequency of Periodic Inspection and Testing' on (P237) and in 652.1 you will find the answer, from the above four options the type of installation and equipment will determine the frequency of PI&T
Explanation: Page 237 - 652.1 - The part 6 contents page (P228) indicates chapter 65 refers to 'Periodic Inspection and Testing - you will find 'Frequency of Periodic Inspection and Testing' on (P237) and in 652.1 you will find the answer, from the above four options the type of installation and equipment will determine the frequency of PI&T
39. What is the appropriate Insulation Resistance test voltage for a 400 v a.c. motor in an industrial installation?
Mark one answer
B
C
D
Correct Answer: D
Explanation: Page 232 - Table 64 - The part 6 contents page (P228) indicates section 643.3 refers to 'Insulation Resistance', you will find Table 64 on page 232. The test voltage for circuits with a nominal voltage up to 500 volts is 500 v d.c.
Explanation: Page 232 - Table 64 - The part 6 contents page (P228) indicates section 643.3 refers to 'Insulation Resistance', you will find Table 64 on page 232. The test voltage for circuits with a nominal voltage up to 500 volts is 500 v d.c.
40. Where new materials are invented for use within electrical installations are departures permitted from BS 7671?
Mark one answer
B
C
D
Correct Answer: D
Explanation: Page 22 - 133.5 - Consulting the Part 1 contents page, we observe section 133.5 'New materials and inventions' Browsing to page 22 you will find 133.5 and we have the answer
Explanation: Page 22 - 133.5 - Consulting the Part 1 contents page, we observe section 133.5 'New materials and inventions' Browsing to page 22 you will find 133.5 and we have the answer
B
C
D
Correct Answer: D
Explanation: Page 20 - 132.8 - Part 1 contents page (P14) indicates 132.8 refers to 'Protective equipment' browsing to page 20 you will find the answer in 132.8. Under-current is not listed here
Explanation: Page 20 - 132.8 - Part 1 contents page (P14) indicates 132.8 refers to 'Protective equipment' browsing to page 20 you will find the answer in 132.8. Under-current is not listed here
Correct Answer: D
Explanation: Page 16 - Exclusions 110.2 (xiii)
Explanation: Page 16 - Exclusions 110.2 (xiii)
43. The cross-sectional area of conductors shall be determined for normal operating conditions and fault conditions according to?
Mark one answer
B
C
D
Correct Answer: A
Explanation: Page 20 - 132.6 (vii) - Part 1 contents page (P14) indicates section 132.6 refers to 'Cross-sectional area of conductors' a quick browse to this section reveals 132.6 (vii) and we have the answer
Explanation: Page 20 - 132.6 (vii) - Part 1 contents page (P14) indicates section 132.6 refers to 'Cross-sectional area of conductors' a quick browse to this section reveals 132.6 (vii) and we have the answer
B
C
D
Correct Answer: D
Explanation: Page 41 - Symbols - Whenever you have a Definitions question involving a symbol e.g. Uf you need to remember; all symbols can be found on pages 40 to 41; a quick browse in the U section reveals Uf is a power frequency fault voltage
Explanation: Page 41 - Symbols - Whenever you have a Definitions question involving a symbol e.g. Uf you need to remember; all symbols can be found on pages 40 to 41; a quick browse in the U section reveals Uf is a power frequency fault voltage
B
C
D
Correct Answer: A
Explanation: Page 25 - Definitions Cable ducting - A nice easy answer. You know it is some form of cable system, so start at 'C' for cable and work your way down those definitions until you find the answer
Explanation: Page 25 - Definitions Cable ducting - A nice easy answer. You know it is some form of cable system, so start at 'C' for cable and work your way down those definitions until you find the answer
46. The arrangements of current-carrying conductors shall be assessed under which of the following conditions?
Mark one answer
B
C
D
Correct Answer: B
Explanation: Page 45 - 312 - The 'key' to answering this question is the term 'shall be assessed' the answer is on the first page of the Part 3 section in section 312
Explanation: Page 45 - 312 - The 'key' to answering this question is the term 'shall be assessed' the answer is on the first page of the Part 3 section in section 312
B
C
D
Correct Answer: D
Explanation: Page 50 - Chapter 51 and Appendix 5 - The Part 3 contents page (P44) indicates that Chapter 32 covers the classification of external influences. On viewing chapter 32 (P50) there is only a reference to Chapter 51, and Appendix 5. Hence, Chapter 51 is the answer
Tip: There are dozens of references to external influences throughout BS 7671, but this is a part 3 question so you are looking for an answer in part 3, not throughout the rest of the big blue book
Explanation: Page 50 - Chapter 51 and Appendix 5 - The Part 3 contents page (P44) indicates that Chapter 32 covers the classification of external influences. On viewing chapter 32 (P50) there is only a reference to Chapter 51, and Appendix 5. Hence, Chapter 51 is the answer
Tip: There are dozens of references to external influences throughout BS 7671, but this is a part 3 question so you are looking for an answer in part 3, not throughout the rest of the big blue book
Correct Answer: B
Explanation: Page 45 - 301.1 (i) - The part 3 contents page (P44) indicates chapter 30 refers to 'Assessment of General Characteristics' where the answer is listed. The other options are NOT. Try to remember when attempting Part 3 questions, any question that refers to 'an assessment of the general characteristics' the answer will probably be found in section 301.1
Explanation: Page 45 - 301.1 (i) - The part 3 contents page (P44) indicates chapter 30 refers to 'Assessment of General Characteristics' where the answer is listed. The other options are NOT. Try to remember when attempting Part 3 questions, any question that refers to 'an assessment of the general characteristics' the answer will probably be found in section 301.1
Correct Answer: D
Explanation: Page 50 - 314.1(vi) - This is a 'Division of installation' type question. The part 3 contents page (P44) indicates section 314 refers to 'Division of installation' in 314.1(vi) you will find the answer
Explanation: Page 50 - 314.1(vi) - This is a 'Division of installation' type question. The part 3 contents page (P44) indicates section 314 refers to 'Division of installation' in 314.1(vi) you will find the answer
Correct Answer: D
Explanation: Page 45 - 312 - As soon as you turn to the part 3 contents page (P44) you see on page 45 'Maximum Demand and Diversity' followed by 312 Conductor Arrangement and System Earthing, within 312 you will find the answer is listed
Explanation: Page 45 - 312 - As soon as you turn to the part 3 contents page (P44) you see on page 45 'Maximum Demand and Diversity' followed by 312 Conductor Arrangement and System Earthing, within 312 you will find the answer is listed
B
C
D
Correct Answer: A
Explanation: Page 52 - 351.1 - The part 3 contents page (P44) indicates 'Safety Services' are referred to in chapter 35 you will find in 351.1 the answer to this question is NOT listed
Explanation: Page 52 - 351.1 - The part 3 contents page (P44) indicates 'Safety Services' are referred to in chapter 35 you will find in 351.1 the answer to this question is NOT listed
Correct Answer: D
Explanation: Page 65 - 411.6.2 - The part 4 contents page provide no guidance to this answer, but you know it's a part 4 question, remember the 13th to 27th question will always be a part 4 question. So, try the chapter 41 contents page (P55) here you will find IT systems can be found in section 411.6, so try here. Turning to page 65 you will find IT systems. In 411.6.2 we are informed RA x Id ≤ 50 V the symbol '≤' means 'less than or equals to' so this regulation is stating RA x Id must be less than or equal to 50 V, or in other words must not exceed 50 V
Explanation: Page 65 - 411.6.2 - The part 4 contents page provide no guidance to this answer, but you know it's a part 4 question, remember the 13th to 27th question will always be a part 4 question. So, try the chapter 41 contents page (P55) here you will find IT systems can be found in section 411.6, so try here. Turning to page 65 you will find IT systems. In 411.6.2 we are informed RA x Id ≤ 50 V the symbol '≤' means 'less than or equals to' so this regulation is stating RA x Id must be less than or equal to 50 V, or in other words must not exceed 50 V
53. In locations where BE2 conditions exist, and where cables are bunched or installed in long vertical runs, the risk to the cables is?
Mark one answer
B
C
D
Correct Answer: A
Explanation: Page 82 - 422.3.4 (bottom of page) - The part 4 contents page (P53) indicates section 422 refers to 'Precautions where particular risks of fire exist'. This is not much use to you if you don't realise the relationship between the contents and the question. You need to remember BE2 conditions occur where there is a risk of fire due to processed or stored materials (See Appendix page 446)
Tip: Cables sagging should not be a problem, cables installed in long vertical runs should be amply supported by cable clips, or cable tray as shown in the image opposite
Vertical cables being supported by cable tray and cable clips
Explanation: Page 82 - 422.3.4 (bottom of page) - The part 4 contents page (P53) indicates section 422 refers to 'Precautions where particular risks of fire exist'. This is not much use to you if you don't realise the relationship between the contents and the question. You need to remember BE2 conditions occur where there is a risk of fire due to processed or stored materials (See Appendix page 446)
Tip: Cables sagging should not be a problem, cables installed in long vertical runs should be amply supported by cable clips, or cable tray as shown in the image opposite
Vertical cables being supported by cable tray and cable clips
Correct Answer: A
Explanation: Page 87 - 430.1 Note 2 - We don't need to consult the part 4 contents page for this question, just go straight to chapter 43 (P87) and start browsing the section. you will find the answer in 430.2 Note 2: e.g. chapter 43 does not take into account external influences.
Tip: Requirements of a chapter are always within the 'Scope' section
Explanation: Page 87 - 430.1 Note 2 - We don't need to consult the part 4 contents page for this question, just go straight to chapter 43 (P87) and start browsing the section. you will find the answer in 430.2 Note 2: e.g. chapter 43 does not take into account external influences.
Tip: Requirements of a chapter are always within the 'Scope' section
Correct Answer: C
Explanation: Page 75 - 417.2 Note: - The part 4 contents page (P53) indicates section 417 refers to 'Obstacles and Placing out of reach' upon opening page 75 you will see Obstacles 417.2 and we have the answer. Whilst the other answer options are valid reasons to use obstacles, they are not the specified BS 7671 answer
Explanation: Page 75 - 417.2 Note: - The part 4 contents page (P53) indicates section 417 refers to 'Obstacles and Placing out of reach' upon opening page 75 you will see Obstacles 417.2 and we have the answer. Whilst the other answer options are valid reasons to use obstacles, they are not the specified BS 7671 answer
B
C
D
Correct Answer: A
Explanation: Page 89 - 433.1.1(ii) - The part 4 contents page (P53) indicates section 433 is for 'Protection against overload current'. The chapter 43 contents page (P86) provides further guidance here you will find that 433.1 refers to 'Co-ordination between conductor and overload protective device' so it would make sense to start here. Browsing to Section 433 (P89) and you will find the answer 433.1.1 (ii), you could have also referred the symbols page 40
Explanation: Page 89 - 433.1.1(ii) - The part 4 contents page (P53) indicates section 433 is for 'Protection against overload current'. The chapter 43 contents page (P86) provides further guidance here you will find that 433.1 refers to 'Co-ordination between conductor and overload protective device' so it would make sense to start here. Browsing to Section 433 (P89) and you will find the answer 433.1.1 (ii), you could have also referred the symbols page 40
Correct Answer: D
Explanation: Page 80 - 421.1.5 Note 1 (a) - The part 4 contents page (P53) indicates section 421 provides 'Protection against fire by electrical equipment' - Going to this section (P79) and browsing down the section you will find on the next page 421.1.5 Note 1 (a) and the answer
Explanation: Page 80 - 421.1.5 Note 1 (a) - The part 4 contents page (P53) indicates section 421 provides 'Protection against fire by electrical equipment' - Going to this section (P79) and browsing down the section you will find on the next page 421.1.5 Note 1 (a) and the answer
B
C
D
Correct Answer: C
Explanation: Page 108 - 444.4.1 - The part 4 contents page (P53) indicates section 444 refers to 'Measures against electromagnetic disturbances' so we will start here on page 108 In 444.4.1 you will find the other answer options are listed as potential sources of electromagnetic disturbance, Immersion heaters is NOT
Explanation: Page 108 - 444.4.1 - The part 4 contents page (P53) indicates section 444 refers to 'Measures against electromagnetic disturbances' so we will start here on page 108 In 444.4.1 you will find the other answer options are listed as potential sources of electromagnetic disturbance, Immersion heaters is NOT
Correct Answer: B
Explanation: Page 62 - Table 41.3 relates to 0.4 and 5 second disconnection times. The answer is in the Type D section, just below the 50-amp m.c.b rating indicating 0.22 ohms. Don't select the value from the 5 sec row by mistake or you will select 0.44 ohms which will be the wrong answer - You need to know Tables 41.2, 41.3, 41.4, 41.5 contain details of maximum tabulated values of earth fault loop impedance for various fuses and MCBs
Explanation: Page 62 - Table 41.3 relates to 0.4 and 5 second disconnection times. The answer is in the Type D section, just below the 50-amp m.c.b rating indicating 0.22 ohms. Don't select the value from the 5 sec row by mistake or you will select 0.44 ohms which will be the wrong answer - You need to know Tables 41.2, 41.3, 41.4, 41.5 contain details of maximum tabulated values of earth fault loop impedance for various fuses and MCBs
B
C
D
Correct Answer: A
Explanation: Page 99 - 442.3 - The part 4 contents page won't point you to this answer, but the Chapter 44 contents page (P95) will. Here you will see 442.3 refers to 'Power frequency stress voltage in the event of a loss of the neutral conductor in TN or TT system' start here. Turning to page 99, you will find in 442.3 that if the neutral conductor becomes disconnected in an energised 3-phase TN or TT system, the voltages between line and neutral conductors can be temporarily increased by the 3-phase line-to-line voltages. This stress voltage can reach up to √3 x U0. If U0 is 415 volts then you need to multiply this by √3, you will find the answer is 718.8 volts. In a 3-phase TN or TT system, such a large voltage can develop between the line-to-line conductors
Explanation: Page 99 - 442.3 - The part 4 contents page won't point you to this answer, but the Chapter 44 contents page (P95) will. Here you will see 442.3 refers to 'Power frequency stress voltage in the event of a loss of the neutral conductor in TN or TT system' start here. Turning to page 99, you will find in 442.3 that if the neutral conductor becomes disconnected in an energised 3-phase TN or TT system, the voltages between line and neutral conductors can be temporarily increased by the 3-phase line-to-line voltages. This stress voltage can reach up to √3 x U0. If U0 is 415 volts then you need to multiply this by √3, you will find the answer is 718.8 volts. In a 3-phase TN or TT system, such a large voltage can develop between the line-to-line conductors