🛁 Special Installations or Locations (Part 7)

1. In a location containing a bath or shower, what is the maximum rated residual operating current of the RCD that must provide additional protection for all circuits serving the location?

1. 10 mA
2. 30 mA
3. 100 mA
4. 300 mA

Regulation 701.411.3.3 requires all circuits serving a location containing a bath or shower to have additional protection by a 30 mA RCD. (BS 7671:2018, Regulation 701.411.3.3)

2. In Section 701, which part of a location containing a bath or shower is defined as Zone 0?

1. The interior of the bath tub or shower basin
2. The area within 0.6 m of the bath rim
3. The space up to 2.25 m above floor level
4. The area outside the room containing the bath

Zone 0 is the interior of the bath tub or shower basin, where the most onerous requirements apply. (BS 7671:2018, Section 701 (zone definitions))

3. Up to what height above the finished floor level does Zone 1 of a location containing a bath or shower generally extend?

1. 1.8 m
2. 2.0 m
3. 2.25 m
4. 2.5 m

In Section 701, Zone 1 extends from the floor up to 2.25 m above the finished floor level. (BS 7671:2018, Section 701 (zone definitions))

4. Measured horizontally, how far does Zone 2 extend beyond the boundary of Zone 1 in a location containing a bath or shower?

1. 0.3 m
2. 0.6 m
3. 1.0 m
4. 1.5 m

Zone 2 extends 0.6 m horizontally beyond the boundary of Zone 1 in a bathroom. (BS 7671:2018, Section 701 (zone definitions))

5. What is the minimum degree of protection against ingress (IP rating) required for equipment installed in Zone 0 of a location containing a bath or shower?

1. IPX4
2. IPX5
3. IPX7
4. IPX8

Regulation 701.512.2 requires a minimum of IPX7 in Zone 0, reflecting the risk of temporary immersion. (BS 7671:2018, Regulation 701.512.2)

6. What is the minimum degree of protection against ingress required for equipment installed in Zones 1 and 2 of a bathroom under normal conditions?

1. IPX1
2. IPX4
3. IPX7
4. IPX8

Regulation 701.512.2 requires a minimum of IPX4 in Zones 1 and 2 under normal conditions. (BS 7671:2018, Regulation 701.512.2)

7. In a bathroom where water jets are likely to be used for cleaning purposes, what minimum degree of ingress protection should equipment in Zones 1 and 2 have?

1. IPX2
2. IPX4
3. IPX5
4. IPX6

Regulation 701.512.2 raises the minimum requirement to IPX5 where water jets are likely to be used for cleaning in those zones. (BS 7671:2018, Regulation 701.512.2)

8. Where SELV is used in Zone 0 of a location containing a bath or shower, what is the maximum permitted nominal voltage?

1. 12 V AC rms or 30 V ripple-free DC
2. 25 V AC rms or 60 V ripple-free DC
3. 50 V AC rms or 120 V ripple-free DC
4. 230 V AC rms

In Zone 0 the SELV nominal voltage is limited to 12 V AC rms or 30 V ripple-free DC, with the safety source located outside the zones. (BS 7671:2018, Section 701 (Regulation 701.414.4.5))

9. Under which circumstances may supplementary equipotential bonding be omitted in a location containing a bath or shower?

1. Only where the bathroom has no metal pipework
2. Where all circuits are RCD protected, main bonding is satisfactory and disconnection times are met
3. Only in domestic dwellings, never in commercial premises
4. Whenever the installation is supplied from a TT system

Regulation 701.415.2 allows supplementary bonding to be omitted where all circuits are 30 mA RCD protected, main equipotential bonding is in place and disconnection times are satisfied. (BS 7671:2018, Regulation 701.415.2)

10. In a location containing a bath or shower, on what condition is a standard 13 A socket-outlet permitted (other than a SELV socket or shaver supply unit)?

1. It is permitted anywhere provided it has additional protection by a 30 mA RCD
2. It is never permitted anywhere within the room under any circumstances
3. It is only permitted if supplied at 400 V three-phase
4. It is only permitted if it has an IP rating of at least IPX8

In BS 7671:2018, a low-voltage socket-outlet other than a SELV socket or shaver supply unit is permitted provided it is located outside the zones and, like all circuits in the location, has additional protection by a 30 mA RCD; the former blanket 3 m rule no longer applies. (BS 7671:2018, Section 701)

11. Which type of low-voltage socket-outlet is permitted within the zones of a bathroom?

1. A standard 13 A BS 1363 socket-outlet
2. A shaver supply unit complying with BS EN 61558-2-5
3. A commando-type industrial socket-outlet
4. An unswitched 16 A socket-outlet

A shaver supply unit to BS EN 61558-2-5, which provides isolation, is the permitted exception for supply within the bathroom zones. (BS 7671:2018, Section 701)

12. What is the purpose of Part 7 of BS 7671 in relation to special installations or locations?

1. It replaces all general requirements of Parts 1 to 6
2. It supplements or modifies the general requirements where the risk is increased
3. It applies only to installations above 1000 V
4. It applies only to temporary supplies on construction sites

Part 7 sets out particular requirements that supplement or modify Parts 1 to 6 for locations where the risk of electric shock or fire is increased. (BS 7671:2018 (IET Wiring Regulations, 18th Edition), Part 7)

13. A luminaire is to be fitted in Zone 1 of a shower room. Which requirement must it satisfy?

1. A minimum of IPX1 with no RCD protection needed
2. A minimum of IPX4 with additional protection by a 30 mA RCD
3. It is prohibited regardless of its IP rating
4. It must be supplied at 400 V three-phase

Equipment in Zone 1 must be at least IPX4 and, like all circuits in the location, have additional protection by a 30 mA RCD. (BS 7671:2018, Regulations 701.512.2 and 701.411.3.3)

14. Where PELV is used to supply equipment in a bathroom, how is protection against electric shock provided?

1. Protection is provided regardless of nominal voltage, by the limited voltage of the PELV system
2. Protection is only required if the voltage exceeds 50 V AC
3. Protection is provided solely by supplementary bonding
4. Protection is not required for PELV circuits in any zone

Where SELV or PELV is used in a bathroom, protection against electric shock must be provided regardless of the nominal voltage of the system. (BS 7671:2018, Section 701 (Regulation 701.414.4.5))

15. Which section of BS 7671 sets out the particular requirements for electric vehicle charging installations?

1. Section 701
2. Section 705
3. Section 722
4. Section 753

Section 722 of BS 7671 contains the particular requirements for electric vehicle charging installations. (BS 7671:2018+A2:2022, Section 722)

16. How must each electric vehicle charging point be protected with respect to residual current devices?

1. By a single 100 mA RCD shared between all charging points
2. By its own dedicated RCD with a rating not exceeding 30 mA
3. By a 300 mA RCD for fire protection only
4. No RCD protection is required for EV charging points

Regulation 722.531.2.101 requires each charging point to be protected by its own dedicated 30 mA RCD (one RCD per connection point). (BS 7671:2018+A2:2022, Regulation 722.531.2.101)

17. For an EV charging point, where DC fault protection is not provided by the charging equipment itself, which RCD arrangement is acceptable?

1. A Type AC RCD only
2. A Type B RCD, or a Type A/F RCD with an RDC-DD that operates at 6 mA DC
3. A Type A RCD with no additional device
4. Any 30 mA RCD regardless of type

Regulation 722.531.3.101 requires a Type B RCD, or a Type A/F RCD combined with a residual direct current detecting device disconnecting at 6 mA DC. (BS 7671:2018, Regulation 722.531.3.101)

18. At what DC residual current must a residual direct current detecting device (RDC-DD) used with an EV charging point cause disconnection?

1. 3 mA
2. 6 mA
3. 10 mA
4. 30 mA

Where a Type A or Type F RCD is used, the associated RDC-DD must disconnect at a DC residual current of 6 mA. (BS 7671:2018, Regulation 722.531.3.101)

19. Why is a Type AC RCD unsuitable for protecting an EV charging point that does not have built-in DC fault detection?

1. Because it cannot interrupt high alternating fault currents
2. Because smooth DC residual currents can blind it, preventing correct operation
3. Because it operates too quickly for EV loads
4. Because it is only rated for three-phase supplies

Smooth DC residual currents from EV chargers can saturate a Type AC RCD's core and prevent it tripping, which is why Type B, or Type A/F with an RDC-DD, is required. (BS 7671:2018, Regulation 722.531.3.101)

20. On a TN-C-S (PME) supply, what does Section 722 require regarding use of the PME earthing facility for an EV charging point?

1. The PME earth may always be used without restriction
2. The PME earth must not be used unless a permitted measure against an open-circuit PEN fault is applied
3. The charging point must always be earthed via the PME terminal
4. The supply must be converted to TN-S before charging is permitted

Regulation 722.411.4.1 prohibits using the PME earthing facility for the charging point unless a permitted protective measure against an open-circuit PEN conductor fault is applied. (BS 7671:2018, Regulation 722.411.4.1)

21. Which of the following is a recognised method of complying with the open-PEN protection requirement for an EV charging point on a PME supply?

1. Increasing the size of the main earthing conductor
2. Using a device that monitors the voltage and disconnects all live conductors on an open-PEN fault
3. Fitting a 300 mA RCD upstream of the charge point
4. Bonding the charge point enclosure to the gas pipe

An open-PEN (voltage detection) device that disconnects the live conductors, including the protective conductor where appropriate, is a permitted measure under Regulation 722.411.4.1. (BS 7671:2018, Regulation 722.411.4.1)

22. What is the principal hazard that the PEN fault protection requirements for EV charging on a PME supply are intended to address?

1. Overheating of the charging cable under normal load
2. A person and the vehicle being raised to a dangerous touch voltage if the PEN conductor goes open-circuit
3. Harmonic distortion affecting nearby equipment
4. Nuisance tripping of the supply RCD

If the supply PEN conductor becomes open-circuit, exposed and extraneous parts including the vehicle can rise to a dangerous voltage, so additional measures are required for outdoor EV charging. (BS 7671:2018, Regulation 722.411.4.1)

23. Which qualification assesses competence in BS 7671:2018, including Part 7 Special Installations or Locations such as EV charging?

1. City & Guilds 2391
2. City & Guilds 2382-22
3. City & Guilds 2365
4. City & Guilds 2377

City & Guilds 2382-22 is the assessment for the IET Wiring Regulations 18th Edition (BS 7671:2018), in which Part 7 is an examinable area. (City & Guilds Level 3 Award 2382-22 (Requirements for Electrical Installations, BS 7671:2018))

24. An installer is wiring a single domestic EV charge point that already incorporates protection against DC fault currents within the unit. Which RCD requirement still applies to that circuit?

1. No RCD is needed because DC protection is built in
2. Additional protection by a 30 mA RCD is still required
3. A 300 mA fire RCD is required instead of a 30 mA RCD
4. A 100 mA time-delayed RCD must be used

Even where the equipment provides its own DC fault protection, the charging point must still have additional protection by a dedicated 30 mA RCD. (BS 7671:2018+A2:2022, Regulations 722.531.2.101 and 722.531.3.101)

25. In a location containing a bath or shower (Section 701), what is the maximum rated residual operating current of the RCD that must provide additional protection for all circuits serving the location?

1. 30 mA
2. 100 mA
3. 300 mA
4. 500 mA

Section 701 requires all circuits serving a location containing a bath or shower to have additional protection by an RCD with a rated residual operating current not exceeding 30 mA. (BS 7671:2018, Regulation 701.411.3.3)

26. According to Section 701, which circuits serving a location containing a bath or shower require additional protection by a 30 mA RCD?

1. Only socket-outlet circuits
2. Only lighting circuits
3. All circuits serving the location
4. Only circuits in Zone 1

Regulation 701.411.3.3 requires additional protection by a 30 mA RCD for all circuits serving the location, not just socket-outlets or those in a particular zone. (BS 7671:2018, Regulation 701.411.3.3)

27. What is the upper vertical limit of Zone 1 in a location containing a bath or shower, measured above the finished floor level?

1. 1.20 m
2. 2.25 m
3. 2.50 m
4. 3.00 m

In Section 701, Zone 1 extends up to 2.25 m above the finished floor level (or to the height of a fixed water outlet if higher). (BS 7671:2018, Section 701 (zone definitions))

28. In a location containing a bath or shower, what horizontal distance defines the extent of Zone 2 beyond the boundary of Zone 1?

1. 0.6 m
2. 1.0 m
3. 1.5 m
4. 2.0 m

Zone 2 extends 0.6 m horizontally beyond the boundary of Zone 1 in a location containing a bath or shower. (BS 7671:2018, Section 701 (zone definitions))

29. What is the minimum degree of protection against ingress (IP rating) for equipment installed in Zone 0 of a location containing a bath or shower?

1. IPX1
2. IPX4
3. IPX5
4. IPX7

Equipment installed in Zone 0 must have a minimum degree of protection of IPX7, reflecting that it may be subject to immersion. (BS 7671:2018, Regulation 701.512.2)

30. What is the minimum degree of protection against ingress required for equipment in Zones 1 and 2 of a bathroom under normal conditions?

1. IPX1
2. IPX4
3. IPX7
4. IP2X

Equipment in Zones 1 and 2 must be at least IPX4; this increases to IPX5 where water jets are likely to be used for cleaning. (BS 7671:2018, Regulation 701.512.2)

31. In which situation must equipment in Zones 1 and 2 of a bathroom have a minimum degree of protection of IPX5 rather than IPX4?

1. Where water jets are likely to be used for cleaning purposes
2. Where the bathroom has no window
3. Where the circuit is RCD protected
4. Where SELV is used

Regulation 701.512.2 raises the minimum from IPX4 to IPX5 in Zones 1 and 2 where water jets are likely to be used for cleaning. (BS 7671:2018, Regulation 701.512.2)

32. An electrician is assessing whether supplementary equipotential bonding can be omitted in a bathroom. Which combination of conditions, if all satisfied, permits its omission?

1. All circuits are RCD protected, main protective bonding is satisfactory, and the required disconnection times are met
2. The bathroom has a window and a fan
3. All accessories are IPX4 and there is a heated towel rail
4. Only the lighting circuit is on an RCD

Regulation 701.415.2 allows supplementary equipotential bonding to be omitted where all circuits have RCD additional protection, main protective bonding is in place and effective, and disconnection times are satisfied. (BS 7671:2018, Regulation 701.415.2)

33. Which volume is defined as Zone 0 in a location containing a bath or shower?

1. The space 0.6 m beyond the bath
2. The interior of the bath tub or shower basin
3. The area up to 2.25 m above the floor
4. The whole room

Zone 0 is the interior of the bath tub or shower basin, the most onerous zone in Section 701. (BS 7671:2018, Section 701 (zone definitions))

34. A shower room contains a shower basin but no bath. Which statement about additional RCD protection is correct?

1. Only the shower circuit needs 30 mA RCD protection
2. No RCD protection is required if all equipment is IPX4
3. All circuits serving the location require 30 mA RCD additional protection
4. RCD protection up to 100 mA is acceptable

Section 701 applies to any location containing a bath or shower; all circuits serving the location require additional protection by a 30 mA RCD. (BS 7671:2018, Regulation 701.411.3.3)

35. Which section of BS 7671 sets out the particular requirements for electrical installations in caravan/camping parks and similar locations (the fixed park installation)?

1. Section 705
2. Section 708
3. Section 721
4. Section 722

Section 708 covers electrical installations in caravan/camping parks and similar locations, including the supply to pitches. (BS 7671:2018, Section 708)