17th edition overview.ppt

Requirements for Electrical InstallationsRequirements for Electrical Installations

BS 7671:2008BS 7671:2008The IEE Wiring RegulationsThe IEE Wiring Regulations

17th Edition17th Edition

An overview of:An overview of:

Presenter:

Jon Elliott BSc (Hons) I Eng MIEEJon Elliott BSc (Hons) I Eng MIEE

Senior Engineer, IET

Representing:

IET - Standards & ComplianceIET - Standards & Compliance

IntroductionIntroduction

A. Preamble

B. The history of BS 7671 C. The Standardization processD. BS 7671:2008

E: Any questions

Topics for today:Topics for today:

This presentation offers an overview of 7671:2008, Requirements for Electrical Installations,

The IEE Wiring Regulations, 17th Edition.

A. PreambleA. Preamble

• BS 7671:2008 was issued 1st January 2008.

• Installations designed between 1st January and 30th

• June 2008 may comply with BS 7671:2001(2004) or BS 7671:2008.

• Installations designed after 30th June 2008 should comply with BS 7671:2008 only.

B. The history of BS 7671B. The history of BS 7671

The Wiring Regulations were first issued in 1882 by the Society of Telegraph Engineers and of Electricians, consisting of four pages and 21 Regulations:


The First Edition had requirements for:


Isolation – Regulation 7:

Mechanical protection and labelling – Regulation 17:

Periodic Inspection and Testing:

The timeline:


Edition Title Year

First Edition Rules and Regulations for the Prevention of Fire Risks Arising from Electric Lighting

1882

Second Edition " 1888

Third Edition General Rules recommended for Wiring for the Supply of Electrical Energy

1897

Fourth Edition " 1903

Fifth Edition Wiring Rules 1907

Sixth Edition " 1911

Seventh Edition " 1916

Eighth Edition Regulations for the Electrical Equipment of Buildings 1924

Ninth Edition " 1927

Tenth Edition " 1934

Eleventh Edition " 1939

Twelfth Edition " 1950

Thirteenth Edition " 1955

Fourteenth Edition " 1966

Fifteenth Edition Regulations for Electrical Installations 1981

Sixteenth Edition Requirements for Electrical Installations 1991

BS 7671:1992, Requirements for Electrical Installations 1992

Seventeenth Edition BS 7671:2008, Requirements for Electrical Installations 2008

In 1991, the Sixteenth Edition of the IEE Wiring Regulations was issued


In 1992, the Sixteenth Edition became a British Standard – BS 7671:1992

BRITISH STANDARD BS 7671:2008

Requirements for Electrical Installations

IEE Wiring Regulations Seventeenth Edition

British Standards

© The Institution of Engineering and Technology and BSI

NO COPYING IN ANY FORM WITHOUT WRITTEN PERMISSION

C. StandardizationC. Standardization

The UK National Committee responsible for BS 7671 is JPEL/64

J Joint IET/BSI CommitteeP PowerEL Electrical64 IEC designation for Committees dealing with low voltage

electrical installations

This is a joint committee between BSI and the IET.

The constitution of JPEL/64 is shown in the early pages of the Regulations.


The work of JPEL/64 is allocated to four sub-Committees:

• Panel A – Verification

• Panel B – Thermal Effects

• Panel C – Protection against Electric Shock

• Panel D – External Influences and Special Locations


JPEL/64 appoints experts to represent the UK at European and International level:


• At European level, the Committee is CENELEC TC 64

• At International level, the Committee is IEC TC 64

Due to the treaty of Rome, the UK are obliged to incorporate the technical intent of Standards developed at the European CENELEC level, i.e. HD – Harmonized Documents.


BS 7671:2008 is largely based on the requirements of the CENELEC HD 60364 series of standards.

HD 60364 is available as a series of standards

www.cenelec.org

D. BS 7671:2008D. BS 7671:2008

Part Title

D. BS 7671:2008D. BS 7671:2008

1. Scope, Object and Fundamental

Principles

2. Definitions

3. Assessment of General Characteristics

4. Protection for Safety

5. Selection and Erection of Equipment

6. Inspection and Testing

7. Special Installations and Locations

Appendices 1-15

Structure of the standard

Numbering System

BS 7671:2008 has adopted the IEC numbering system:

• Single digit indicates the Part, e.g. Part 4

• Two digits indicates the Chapter, e.g. Chapter 41

• Three digits indicates the Section, e.g. Section 411

One or more further digits are added, separated by points, to identify Regulation groups or individual Regulations.

D. BS 7671:2008D. BS 7671:2008

Numbering System - Developing the example:

Part 4 - Protection for Safety

Chapter 41 - Protection against Electric Shock

Section 411 - Protective Measure: Automatic Disconnection of Supply

411.3 Requirements for fault protection

411.3.1 Protective earthing and protective equipotential bonding

411.3.1.1 Protective earthing: Exposed-conductive-parts shall be

connected by a protective conductor…

D. BS 7671:2008D. BS 7671:2008

Appendices

The number of Appendices has been more than doubled - from 7 to 15.

Seven existing Appendices are retained:

D. BS 7671:2008D. BS 7671:2008

1. British Standards to which reference is made in the Regulations2. Statutory regulations and associated memoranda3. Time/current characteristics of overcurrent protective devices4. Current carrying capacity and voltage drop for cables and flexible

cords5. Classification of external influences6. Model forms for certification and reporting7. Harmonized cable core colours

cont….

Appendices

Eight new Appendices are added:

D. BS 7671:2008D. BS 7671:2008

8. Current-carrying capacity and voltage drop for busbar trunking and powertrack systems

9. Definitions – multiple source, d.c. and other systems10. Protection of conductors in parallel against overcurrent11. Harmonic currents in three-phase systems12. Voltage drop in consumers’ installations13. Methods for measuring insulation resistance of floors and walls14. Measurement of fault loop impedance: increase of resistance of

conductors with temperature15. Radial and ring circuit arrangements

Part 1 – Part 1 – Scope, Object and Fundamental PrinciplesScope, Object and Fundamental Principles

D. BS 7671:2008D. BS 7671:2008

There are three Chapters in Part 1:

Chapter 11 ScopeChapter 12 Object And EffectsChapter 13 Fundamental Principles

PART 1 Scope, Object and Fundamental Principles

D. BS 7671:2008D. BS 7671:2008

Scope

110.1 GENERAL

The Regulations apply to the

design, erection and verification

of electrical installations such as

those of:

D. BS 7671:2008D. BS 7671:2008


(ix) marinas(xi) mobile or transportable units(xii) photovoltaic systems(xiii) low voltage generating sets

D. BS 7671:2008D. BS 7671:2008


Object and Effects

120.3 This Standard sets out technical requirements…

Any intended departure…requires special consideration by the designer…The resulting degree of safety of the installation shall be not less than that obtained by compliance with the Regulations.

D. BS 7671:2008D. BS 7671:2008


Fundamental Principles

131.8 No addition or alteration, temporary or permanent, shall be made to an existing installation, unless…the rating and the condition of any existing equipment, including that of the distributor, will be adequate…. the earthing and bonding arrangements, if necessary for the protective measure applied for the safety of the addition or alteration, shall be adequate.

132.3 The number and type of circuits …knowledge of: (vi) anticipated future demand if specified.

132.13 Every electrical installation shall be provided with appropriate documentation…

134.1.1 Good workmanship by competent persons or persons under their supervision and proper materials …

Part 2 –Part 2 –DefinitionsDefinitions

D. BS 7671:2008D. BS 7671:2008

D. BS 7671:2008D. BS 7671:2008

PART 2 Definitions

The definitions used Part 2 are extracted from the IEC International Electrotechnical Vocabulary (IEV), Part 826 – IEC 60050.

Where UK only terms are used in BS 7671, the definitions have been developed by JPEL/64.

223 terms are defined in the 17th Edition, whilst 151 are defined in the 16th!

D. BS 7671:2008D. BS 7671:2008

PART 2 Definitions

Competent PersonA person who possesses sufficient technical knowledge and experience for the nature of the electrical work undertaken and is able at all times to prevent danger, and where appropriate, injury, to him/herself and others.

This definition is aligned with the Memorandum of guidance on the Electricity at Work Regulations 1989 (HS(R)25)

D. BS 7671:2008D. BS 7671:2008

PART 2 Definitions

Basic Protection

Protection against electric shock

under fault-free conditions.

Basic protection replaces the term Direct Contact

Fault Protection

Protection against electric shock

under single fault conditions.

Fault protection replaces the term Indirect Contact

D. BS 7671:2008D. BS 7671:2008

PART 2 Definitions

Line conductor(replaces the term Phase conductor but definition unchanged)

Exposed-conductive-partA conductive part of equipment which can be touched and which is not normally live but which can become live when basic insulation fails.

Part 3 –Part 3 –Assessment of General CharacteristicsAssessment of General Characteristics

D. BS 7671:2008D. BS 7671:2008

D. BS 7671:2008D. BS 7671:2008

PART 3 Assessment of General Characteristics

Part 3 is the starting point for:

• designing a new installation• a major addition, or • alteration to an existing installation

D. BS 7671:2008D. BS 7671:2008


There are six Chapters in Part 3:

Four are existing:

Chapter 31 Purpose, Supplies and StructureChapter 32 Classification of External InfluencesChapter 33 CompatibilityChapter 34 Maintainability

Two are new:

Chapter 35 Safety ServicesChapter 36 Continuity of Service

D. BS 7671:2008D. BS 7671:2008


Chapter 35, Safety Services, requires that an assessment is made of any need for safety services, such as:

• Emergency escape lighting• Fire alarm systems• Fire rescue lifts• Smoke extractors

D. BS 7671:2008D. BS 7671:2008


Chapter 36, Continuity of Service, requires an assessment of any need for continuity of service:

• life-support systems

D. BS 7671:2008D. BS 7671:2008


311 MAXIMUM DEMAND AND DIVERSITY

311.1 For economic and reliable design, the maximum demand of an installation shall be assessed. In determining the maximum demand….., diversity may be taken into account.

Note the addition of “For economic and reliable design”.

• underrated equipment could lead to overloading, early failure, or loss of supply

• overestimating the maximum demand may increase tariff costs for the client.

D. BS 7671:2008D. BS 7671:2008


Section 314 – Division of an Installation

Was Installation Circuit Arrangement in 16th Edition.Now renamed Division of Installation. This emphasizes the need to split an installation into a suitable number and arrangement of circuits.

Part 4 –Part 4 –Protection for SafetyProtection for Safety

D. BS 7671:2008D. BS 7671:2008

There are four Chapters in Part 4, trimmed down from nine:

Chapter 41 Protection against electric shock

Chapter 42 Protection against thermal effects

Chapter 43 Protection against overcurrent

Chapter 44 Protection against voltage disturbances and electromagnetic disturbances

Many changes have occurred in Part 4, both technical and editorial.

D. BS 7671:2008D. BS 7671:2008

PART 4 - Protection for Safety

D. BS 7671:2008D. BS 7671:2008


Correlation of Chapters and Sections between 16th and 17th Edition, i.e. where’s it gone….:

16th Edition 17th Edition

Ch 41, Sec. 471 Ch 41

Ch 42, Ch 48 Ch 42

Ch 43, Sec. 473 CH 43

Ch 44, Ch 45 CH 44

Ch 46, Sec. 476 Sec 537

D. BS 7671:2008D. BS 7671:2008


Chapter 41 - Protection for against electric shock

The terms direct contact and indirect contact are no longer used in the Regulations, they have been replaced by Basic Protection and Fault protection.

Basic Protection Protection against electric shock under fault-free conditions.

Fault Protection Protection against electric shock under single fault conditions.

D. BS 7671:2008D. BS 7671:2008

PART 4 - Protection for Safety Chapter 41 - Protection for against electric shock

410.3.3 In each part of an installation one or more protective measures shall be applied.

The following protective measures generally are permitted:

i). automatic disconnection of supplyii). double or reinforced insulationiii). electrical separation for supply to one

item of current-using equipmentiv). extra-low voltage (SELV and PELV)

D. BS 7671:2008D. BS 7671:2008


410.3.2A protective measure shall consist of:

(i) an appropriate combination of a provision for basic protection and an independent provision for fault protection, or

(ii) an enhanced protective provision which provides both basic protection and fault protection.

D. BS 7671:2008D. BS 7671:2008


411 Protective Measure – Automatic disconnection of supply

411.1 Automatic disconnection of supply (was EEBADS) is a protective measure in which:

(i) basic protection is provided by basic insulation of live parts or by barriers or enclosures…

(ii) fault protection is provided by protective earthing, protective equipotential bonding and automatic disconnection in case of a fault…

D. BS 7671:2008D. BS 7671:2008

Fault Protection

Three components, much the same as EEBADS

(a) Protective earthing

(b) Protective equipotential bonding

(c) Automatic disconnection in case of a fault



D. BS 7671:2008D. BS 7671:2008



Fault Protection

D. BS 7671:2008D. BS 7671:2008


Chapter 41 - Protection for against electric shock 411 Protective Measure – Automatic disconnection of supply

Disconnection times

411.3.2.2 TABLE 41.1 (part of) maximum disconnection times for final circuits not exceeding 32A

System

120V < Uo ≤ 230V (s)

a.c. d.c.

TN 0.4 5

TT 0.2 0.4

D. BS 7671:2008D. BS 7671:2008



Disconnection times

Distribution circuits and circuits not covered by Table 41.1:

411.3.2.3 TN: 5 s maximum

411.3.2.4 TT: 1 s maximum

411.8.3 Reduced low-voltage systems: 5 s maximum

559.10.3.3 Outdoor lighting installations: 5 s maximum

D. BS 7671:2008D. BS 7671:2008



RCD protection in a TT system

411.5.3 Where an RCD is used for earth fault protection, the following conditions shall be fulfilled:

(i) disconnection time (prescribed earlier)

(ii) RA x I∆n ≤ 50 V

where RA = sum of resistances of electrode and protective conductor to exposed-conductive-parts

I∆n = RCD rated residual current

D. BS 7671:2008D. BS 7671:2008



Tables showing maximum earth fault loop impedance i.e. 41.2, 41.3 and 41.4, have been corrected to reflect the adoption of Uo (230 v) over Uoc (240 v)

16th Edition

17th Edition

D. BS 7671:2008D. BS 7671:2008

PART 4 - Protection for SafetyChapter 41 - Protection for against electric shock


Additional protection

411.3.3 Additional protection

In a.c. systems, additional protection by means of an RCD (having I∆n not exceeding 30 mA) shall be provided for:

(i) socket-outlets not exceeding 20 A rating for use by ordinary persons and intended for general use, and (ii) mobile equipment not exceeding 32 A rating for use outdoors.

D. BS 7671:2008D. BS 7671:2008


Chapter 41 - Protection for against electric shock 411 Protective Measure – Automatic disconnection of supply

Additional protection

411.3.3 An exception is permitted for:

(i) socket-outlets for use under supervision of skilled or instructed persons, e.g. in some commercial or industrial locations, or

(ii) a specific labeled or otherwise suitably identified socket-outlet provided for connection of a particular item of equipment.

D. BS 7671:2008D. BS 7671:2008


Chapter 41 - Protection for against electric shock 412 Double Or Reinforced Insulation

412.1.1 Double or reinforced insulation…(i) basic protection is provided by basic insulation fault protection is provided by supplementary insulation, or(ii) basic and fault protection are provided by reinforced insulation between live parts and accessible parts.

412.1.3 Where this protective measure is to be used as the sole protective measure, it shall be verified that the installation or circuit concerned will be under effective supervision in normal use so that no change is made that would impair the effectiveness of the protective measure.

D. BS 7671:2008D. BS 7671:2008


413 Electrical Separation

413.1.1 Electrical separation is a protective measure in which:

(i) basic protection is provided by basic insulation of live parts or by barriers or enclosures in accordance withSection 416, and

(ii) fault protection is provided by simple separation of the separated circuit from other circuits and from Earth.

D. BS 7671:2008D. BS 7671:2008


414 ELV Provided by SELV or PELV

414.1.1 Protection by extra-low voltage consists of either of two different extra-low voltage systems:

(i) SELV, or(ii) PELV.

Protection by SELV or PELV requires:(i) limitation of voltage - 50 V a.c. or 120 V d.c., and(ii) protective separation of the SELV or PELV system from

all circuits other than SELV and PELV circuits, and basicinsulation between the SELV or PELV system and other

SELV or PELV systems, and(iii) for SELV systems only, basic insulation between the SELV

system and Earth.

414.1.2 The use of SELV or PELV is considered as a protective measure in all situations.

Part 5 –Part 5 –Selection and Erection of EquipmentSelection and Erection of Equipment

D. BS 7671:2008D. BS 7671:2008

There are six Chapters in Part 5:

Chapter 51 Common rulesChapter 52 Selection and Erection of Wiring SystemsChapter 53 Protection, Isolation, Switching, Control and

MonitoringChapter 54 Earthing Arrangements and Protective

ConductorsChapter 55 Other EquipmentChapter 56 Safety Services

D. BS 7671:2008D. BS 7671:2008

Part 5 –Selection and Erection of Equipment

D. BS 7671:2008D. BS 7671:2008

Part 5 –Selection and Erection of Equipment Chapter 51 - Common rules

514 Identification and Notices

514.15 Warning notice – dual supply

514.15.1 Where an installation includes a generating set which is used as an additional source of supply in parallel with another source, warning notices shall be affixed:

D. BS 7671:2008D. BS 7671:2008

Part 5 –Selection and Erection of Equipment Chapter 52 - Selection and Erection of Wiring Systems

522 External Influences

Concealed cables in walls or partitions

522.6.6 Cable concealed in a wall, less than 50 mm deep…shall:

(i) have earthed metallic covering(ii) be enclosed in earthed metallic conduit(iii) be enclosed in earthed metallic trunking(iv) be mechanically protected from screws, etc.(v) installed in zones (see next slide…):

D. BS 7671:2008D. BS 7671:2008



Concealed cables in walls or partitions …cont

522.6.6 Cable concealed in a wall, less than 50 mm deep…shall:

(v) installed in zones:

D. BS 7671:2008D. BS 7671:2008




522.6.7 Cable concealed in a wall:

• less than 50 mm deep• not under supervision of skilled or instructed person• no earthed mechanical protection

RCD protection at 30 mA to be provided

D. BS 7671:2008D. BS 7671:2008




522.6.8 Irrespective of the depth of the cable and not under the supervision of a skilled or instructed person, a cable concealed in a wall or partition the internal construction of which includes metallic parts… shall:

(i) incorporate an earthed metallic covering, or (ii) be enclosed in earthed conduit, or (iii) be enclosed in earthed trunking, or(iv) be sufficiently mechanically protected sufficiently, or(v) RCD protection at 30 mA to be provided

NOTE: If the cable is installed at a depth of 50 mm or less from the surface of a wall or partition the requirements of Regulation 522.6.6 also apply.

D. BS 7671:2008D. BS 7671:2008



Concealed cables in walls or partitions…cont

522.6.8 .. a cable concealed in a wall or partition the internal construction of which includes metallic parts:

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523 Current-Carrying Capacities of Cables

Cables in thermal insulation

523.7 Changes:The derating factors in Table 52.2 are appropriate to conductor sizes up to 10 mm² in thermal insulation having a thermal conductivity (λ) greater than 0.04 Wm-¹K-¹.

D. BS 7671:2008D. BS 7671:2008


525 Voltage Drop in Consumer’s Installations

The requirements are deemed to be satisfied if the voltage drop between the origin of the installation (usually the supply terminals) and any socket-outlet or the terminals of fixed current-using equipment does not exceed that stated in Appendix 12.

D. BS 7671:2008D. BS 7671:2008

Part 5 –Selection and Erection of Equipment Chapter 54 - Earthing Arrangements and Protective Conductors

542 Earthing Arrangements

542.2.4 A metallic pipe for gases or flammable liquids shall not be used as an earth electrode. The metallic pipe of a water utility supply shall not be used as an earth electrode.

Other metallic water supply pipework shall not be used as an earth electrode unless precautions are taken against its removal and it has been considered for such a use.

D. BS 7671:2008D. BS 7671:2008

Part 5 –Selection and Erection of Equipment Chapter 54 - Earthing Arrangements and Protective Conductors

543 Protective Conductors

543.7 Earthing requirements for the installation of equipment having high protective conductor currents

The technical intent of Section 607 (BS 7671:2001(2004) is now included here; Section 607 has now been deleted.

D. BS 7671:2008D. BS 7671:2008

Part 5 –Selection and Erection of Equipment Chapter 55 – Other Equipment

551 Low Voltage Generating Sets

551.7.1 Where a generating set is used as an additional source of supply in parallel with another source, protection against thermal effects in accordance with Chapter 42 and protection against overcurrent in accordance with Chapter 43 shall remain effective in all situations.

D. BS 7671:2008D. BS 7671:2008



551.7.2 A generating set used as an additional source of supply in parallel with another source shall be installed:

• on the supply side of all the protective devices for the final circuits of the installation, or

D. BS 7671:2008D. BS 7671:2008



551.7.2 A generating set used as an additional source of supply in parallel with another source shall be installed:

• on the load side of all the protective devices for a final circuit of the installation

In this case all the following additional requirements shall be fulfilled:

D. BS 7671:2008D. BS 7671:2008



551.7.2 (i) The conductors of the final circuit shall meet the following requirement:

Iz ≥ In + Igwhere:Iz is the current-carrying capacity of the final circuit conductorsIn is the rated current of the protective device of the final circuit

Ig is the rated output current of the generating set, and

(ii) not be connected to a final circuit by plug and socket, and(iii) A 30 mA RCD on the final circuit shall disconnect all live

conductors (iv) The line and neutral conductors of the final circuit and of

the generating set shall not be connected to Earth(v) Disconnection times must still be met.

D. BS 7671:2008D. BS 7671:2008


559 Luminaires and Lighting Installations

This section applies to the selection and erection of luminaires and lighting installations intended to be part of the fixed installation and to highway power supplies and street furniture

Particular requirements are given for:

• fixed outdoor lighting installations

• extra-low voltage lighting installations supplied from a source of maximum rated voltage of 50V a.c or 120V d.c

• lighting for display stands

Part 6 –Part 6 –Inspection and TestingInspection and Testing

D. BS 7671:2008D. BS 7671:2008

There are three Chapters in Part 6:

Chapter 61 Initial Verification

Chapter 62 Periodic Inspection and Testing

Chapter 63 Certification and Reporting

D. BS 7671:2008D. BS 7671:2008

Part 6 – Inspection and Testing

D. BS 7671:2008D. BS 7671:2008

Part 6 – Inspection and Testing Chapter 61 – Initial Verification

612 Testing

612.3 Insulation resistanceNote changes to minimum values of insulation resistance:

D. BS 7671:2008D. BS 7671:2008


612 Testing

Phase sequence

612.12

In case of multiphase circuits, it shall be verified that the phase sequence is maintained.

D. BS 7671:2008D. BS 7671:2008


612 Testing

612.14 Verification of voltage drop

Where required to verify compliance with Section 525, the following options may be used:

(i) the voltage drop may be evaluated by measuring the circuit impedance;

(ii) the voltage drop may be evaluated by using the information given in Appendix 12

NOTE: Verification of voltage drop is not normally required during initial verification.

Part 7 –Part 7 –Special Installations or LocationsSpecial Installations or Locations

D. BS 7671:2008D. BS 7671:2008

There are fourteen Special Installations or Locations in Part 7:

701 Locations containing a bath or shower702 Swimming pools and other basins703 Rooms and cabins containing sauna heaters704 Construction and demolition site installations705 Agricultural and horticultural premises706 Conducting locations with restricted movement707 Not used (was Section 607, now in Chapter 54)708 Electrical installations in caravan / camping parks

and similar locations

D. BS 7671:2008D. BS 7671:2008

Part 7 – Special Installations or Locations

There are fourteen Special Installations or Locations in Part 7:

709 Marinas and similar locations710 Medical locations, reserved for future use711 Exhibitions, shows and stands712 Solar photovoltaic (pv) power supply systems717 Mobile or transportable units721 Electrical installations in caravans and motor caravans740 Temporary electrical installations for structures, amusement devices and booths at fairgrounds, amusement parks and circuses753 Floor and ceiling heating systems

D. BS 7671:2008D. BS 7671:2008


D. BS 7671:2008D. BS 7671:2008

Description of Zones

No Zone 3 No Zone 2 for showers without basins


701 Locations containing a bath or shower



D. BS 7671:2008D. BS 7671:2008



D. BS 7671:2008D. BS 7671:2008

D. BS 7671:2008D. BS 7671:2008

Additional protection by RCDs

701.411.3.3

Additional protection shall be provided for all circuits of the location, by the use of one or more RCDs rated at 30 mA



D. BS 7671:2008D. BS 7671:2008



Supplementary equipotential bonding

701.415.2 Supplementary bonding in the location may be omitted providing:

(i) All final circuits comply with the requirements for automatic disconnection, and

(ii) all final circuits have additional protection by means of a 30 mA RCD, and

(iii) all extraneous-conductive-parts of the location are effectively connected to the protective

equipotential bonding.

D. BS 7671:2008D. BS 7671:2008



Socket outlets

701.512.3 (part of)

Socket-outlets other than SELV sockets or shaver supply units are prohibited within a distance of 3m horizontally from the boundary of zone 1.

D. BS 7671:2008D. BS 7671:2008


702 Swimming pools and other basins

Zoning arrangements

Zones are now defined using numbers, rather than letters:

D. BS 7671:2008D. BS 7671:2008



702.55.4 Special requirements for the installation of electrical equipment in zone 1 of swimming pools and other basins

Subject to all the following requirements being met:

(i) located inside a Class II enclosure, and

(ii) accessible via a hatch by key or a tool. Opening the hatch will disconnect all live conductors, and

(iii) the supply circuit of the equipment shall be protected by:– SELV (25 V a.c. rms or 60 V d.c.), or– an RCD rated at 30 mA– electrical separation.

D. BS 7671:2008D. BS 7671:2008



702.55.4 Special requirements for the installation of electrical equipment in zone 1 of swimming pools and other basins

…cont

Where there is no zone 2, lighting other than a SELV source may be installed in zone 1 provided that the following requirements are fulfilled:

- the circuit is protected by automatic disconnection of the supply, and

- additional protection is provided by an RCD rated at 30 mA, and

- the height from the floor is at least 2 m above the lower limit of zone 1.

In addition, every luminaire shall have an enclosure providing Class II.

D. BS 7671:2008D. BS 7671:2008


703 Rooms and Cabins Containing Sauna Heaters

Zones now numeric

703.411.3.3 Additional protection by RCDs

Additional protection shall be provided for all circuits of the sauna, by means of one or more 30 mA RCDs.

RCD protection need not be provided for the sauna heater unless such protection is recommended by the manufacturer.

D. BS 7671:2008D. BS 7671:2008


704 Construction and demolition sites

General requirements

704.410.3.10 A circuit supplying a socket-outlet with a rated current up to and including 32 A and any other circuit supplying hand-held electrical equipment with a rated current up to and including 32A shall be protected by:

(i) reduced low voltage (110v, i.e. 55-0-55), or

(ii) automatic disconnection of supply by a 30 mA RCD, or

(iii) electrical separation, or

(iv) SELV or PELV

D. BS 7671:2008D. BS 7671:2008


704 Construction and demolition sites


704.411.3.1.2

A TN-C-S system shall not be used for the supply to a construction site, except for the supply to a fixed building of the construction site.

D. BS 7671:2008D. BS 7671:2008


705 Agricultural and horticultural premises


705.411.1 In circuits, whatever the type of earthing system, the following disconnection devices shall be provided:

(i) socket-outlets up to 32 A, a 30 mA RCD

(ii) socket-outlets over 32A, a 100 mA RCD

(iii) all other circuits, a 300 mA RCD.

D. BS 7671:2008D. BS 7671:2008


706 Conducting Locations with Restricted Movement


706.410.3.10 The following protective measures apply to circuits supplying the following current-using equipment:

(i) supply to a hand-held tool or an item of mobile equipment:a) electrical separation, orb) SELV

(ii) SELV for the supply to handlamps

(iii) for the supply to fixed equipment:a) automatic disconnection with supplementary equipotential bondingb) by use of Class II equipment and additional protection by the use of RCDs at 30 mAc) electrical separation, ord) SELV, ore) PELV

D. BS 7671:2008D. BS 7671:2008


708 Caravan/Camping Parks and Similar Locations


708.411.4 TN-C-S shall not be used other than for supplies to permanent buildings

708.521.1.1 Underground cables shall be at least 0.6 m below ground

708.553.1.9 Socket-outlet mounting height to be 0.5 m to 1.5 m above ground

708.553.1.13 Each pitch socket-outlet shall be protected individually by a 30 mA RCD

D. BS 7671:2008D. BS 7671:2008


709 Marinas and Similar Locations


709.1 Scope - Applies only to circuits intended to supply pleasure craft or houseboats in marinas and similar locations

Does not apply to:

• houseboats directly supplied from the public network

• internal electrical installations of pleasure craft or houseboats

D. BS 7671:2008D. BS 7671:2008


711 Exhibitions, shows and stands


711.1 Scope: Applies to temporary electrical installations in exhibitions, shows and stands, including

mobile and portable displays and equipmentDoes not apply to:

• the building in which the event is occurring• electrical systems used in structures, sets, etc., of

production and similar activities of the entertainment industry

• the exhibits themselves

D. BS 7671:2008D. BS 7671:2008


711 Exhibitions, shows and stands


711.410.3.4 Supply cable protected at its origin by a 300 mA RCD

711.411.3.1.2 Protective bonding of all metallic structural parts

711.411.3.3 Additional protection is required for all final circuits and socket-outlets up to 32 A by a 30 mA RCD

D. BS 7671:2008D. BS 7671:2008


711 Solar Photovoltaic (pv) Power Supply Systems


712.1 Scope - Applies to the electrical installations of PV power supply systems including systems with a.c. modules.

712.410.3 PV equipment on the d.c. side shall be considered energized, even when the system is disconnected from the a.c. side.

712.411.3.2.1.1 On the a.c. side, the PV supply cable shall be connected to the supply side of the device supplying current-using equipment.

D. BS 7671:2008D. BS 7671:2008


717 Mobile or transportable units


717.1 Scope: The particular requirements of this section apply to mobile or transportable units

Units are either mobile vehicles (self-propelled or towed), or transportable (containers or cabins)

Examples include:

• outside broadcast trucks• medical services• fire fighting appliances

D. BS 7671:2008D. BS 7671:2008




717.411.1 Automatic disconnection shall be by RCD

717.411.3.1.2 Accessible conductive parts of the unit to beconnected through the main equipotential bonding to the mainearth terminal within the unit.

D. BS 7671:2008D. BS 7671:2008




717.514 Identification adjacent to the supply inlet:

(i) the type of supply which may be connected(ii) the voltage rating of the unit(iii) the number of phases and their configuration (iv) the on-board earthing

arrangements (v) the maximum power

required by the unit.

D. BS 7671:2008D. BS 7671:2008


740 Temporary Electrical Installations for Structures, Amusement Devices and Booths at Fairgrounds, Amusement Parks and Circuses


740.1.1 Scope - This section specifies the minimum electrical installation requirements to facilitate the safe design, installation and operation of temporarily erected mobile or transportable electrical machines and structures which incorporate electrical equipment…

…intended to be installed repeatedly, without loss of safety, temporarily, at fairgrounds, amusement parks and similar places…

D. BS 7671:2008D. BS 7671:2008


75 3Floor and ceiling heating systems


753.1 Scope: This section applies to the installation of electric floor and ceiling heating systems, either thermal storage or direct heating systems

It does not apply to wall heating or outdoor heating systems

The risk is one of penetration of the element

D. BS 7671:2008D. BS 7671:2008


753 Floor and ceiling heating systems


753.411.3.2 30 mA RCDs shall be used for automatic disconnection of supply.

Heating units manufactured without exposed conductive-parts shall be provided on site with a grid with spacing of not more than 30 mm, or other suitable conductive covering above the floor heating or below the ceiling heating and connected to the protective conductor of the installation.

Appendices – 1-15Appendices – 1-15

D. BS 7671:2008D. BS 7671:2008

There are fifteen Appendixes:

1 British Standards - reference made in the Regulations2. Statutory regulations and associated memoranda3. Time/current characteristics of overcurrent protective devices4. Current-carrying capacity and voltage drop for cables5. Classification of external influences6. Model forms for certification and reporting7. Harmonized cable core colours8. Current-carrying capacity and voltage drop for busbar trunking and powertrack systems9. Definitions-Multiple source, d.c. and other systems10. Protection of conductors in parallel against overcurrent11. Harmonic currents in three-phase systems 12. Voltage drop in consumers’ installations13. Methods for measuring insulation resistance of floors and walls14. Measurement of fault loop impedance: increase of resistance of conductors with

temperature15. Radial and ring final circuit arrangements

D. BS 7671:2008D. BS 7671:2008

Appendices

Thank you for listening

Any questions?

D. BS 7671:2008D. BS 7671:2008