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2. The risks Scope The zones Supplementary bonding Wiring systems Switchgear and controlgear Fixed current-using equipment Other equipment, example, washing machines. 601. OVERVIEW ON LOCATIONS CONTAINING A BATH OR SHOWER. 601. 2.

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overview on locations containing a bath or shower

2

The risks

Scope

The zones

Supplementary bonding

Wiring systems

Switchgear and controlgear

Fixed current-using equipment

Other equipment, example, washing machines

601

OVERVIEW ON LOCATIONS CONTAININGA BATH OR SHOWER
slide2

601

2

THE RISKSPersons in bathrooms are particularly at risk because of a reduction of body impedance due to:

a) lack of clothing, particularly footwearb) presence of water reducing contact resistancec) immersion in water, reducing total body resistanced) ready availability of earthed metale) increased contact area

scope

2

601

SCOPE
  • Applies to locations containing baths or showers.
  • Does not apply to emergency facilities in industrial areas and laboratories.
  • Special requirements for medical treatment, or for disabled persons.
  • Bedrooms with a shower cubicle -

requirements for bathrooms are to be met except that socket-outlets are allowed in bedrooms provided they are outside of zones 0, 1, 2 or 3 and protected by an RCD, also, Supplementary bonding, is only required in zones 1 and 2.

slide4

2

zone 2

zone 1

2.25 m

2.4 m 0.6 m

zone 3 zone 2 zone 1 zone 2 zone3

zone 2

zone 3

601

the zones

2

601

THE ZONES
  • Zones 0, 1, 2 and 3 provide a method of specifying
  • requirements for protection against the ingress of water and
  • protection against electric shock, supplementary bonding, etc
  • The zones are determined taking account of walls, doors, fixed
  • partitions, ceilings and floors.
slide6

2

601

wiring systems

2

601

WIRING SYSTEMS
  • Metal conduit and metal trunking wiring systems are allowed in the

zones of bathrooms provided they

are supplementary bonded within

the zones.

  • They do not have to supply equipment within the zones.
supplementary bonding

2

601

Supplementary Bonding
  • Local supplementary equipotential bonding complying with Reg 547-03 shall be provided.
  • Connecting together the terminal of the protective conductor of each circuit supplying Class I and Class II equipment in zones 1, 2 or 3, and extraneous-conductive-parts in these zones.
  • The supplementary equipotential bonding may be provided in close proximity to the location.
slide9

2

601

Figure showing Supplementary Bonding

in a bathroom – metal pipe installation

with soldered joints providing reliable electrical continuity

switchgear and controlgear

601

2

Switchgear and Controlgear
  • Switches other than those for SELV circuits are not allowed in zones 0, 1, or 2.
  • This does not apply to switches and controls incorporated into fixed equipment suitable for use in the zones.
  • Socket-outlets Other than SELV and shaver sockets are not allowed in bathrooms or shower rooms, whatever the size of the room.
slide11

2

601

  • A plate switch is allowed within zone 3 and outside the zones of a bathroom.
  • A switch should be at least 0.6 metres from the edge of the bath or shower and must be suitable for the location. It is recommended that plate switches be installed outside of zone 3.
  • The cords of cord-operated switches are allowed in zones 1, 2 and 3.
fixed current using equipment

2

601

Fixed current-using equipment
  • Fixed current-using equipment may be installed in zones 1, 2, 3 and outside the zones but there are specific requirements for degrees of protection and it may be necessary to protect the circuit with an RCD.
  • 230 V equipment may be installed in the above zones provided it has the appropriate IP rating and is suitable for use in the zone.
slide13

2

601

Extractor Fans

  • A suitable 230 V extractor fan may be installed in zones 1 and 2 as well as zone 3 and outside the zones.
  • Must be IPX4 in zone 1 or 2
  • An extractor fan supplied from a lighting circuit for a bathroom without a window should have its own means of isolation, as otherwise replacement or maintenance of the fan would have to be carried out in the dark.
extractor fans

2

601

Example of duct mounted extract fan

Extractor Fans
electric showers

2

601

Electric Showers

Electric showers and electric shower pumps should comply with BS EN 60335-2-35 and BS EN 60335-2-41 respectively.

Usually suitable for installation within zone 1. Not required by BS 7671 to be protected by an RCD, however, often shower manufacturers recommend an RCD

Normal practice to provide an isolation switch within the bathroom. The switch must be installed outside zones 0, 1 and 2 although the cord of cord operatedswitches may reach into zones 1 or 2.

other equipment eg washing machines and tumble dryers

2

601

Other Equipmenteg: washing machines and tumble dryers

Washing machines and tumble dryers may be installed in a bathroom (if suitable) provided they are:

  • Installed outside zones 0, 1 and 2
  • Supplied from a switched fused flex outlet installed outside zones 0, 1 and 2
  • Protected by a 30 mA RCD.
2 overview on locations containing swimming pools

2

602

2. OVERVIEW ON LOCATIONS CONTAINING SWIMMING POOLS

Swimming Pools

  • The risks
  • Scope
  • Summary of the additional supplementaryrequirements placed by Section 602 of BS 7671.
  • The future – 17th edition.
the risks

2

602

The Risks
  • Persons in swimming pools are

particularly at risk because of a

reduction in body resistance and

contact of the body with earth potential.

scope19

2

602

Scope
  • The particular requirements of this section shall apply to basins of swimming pools and paddling pools and their surrounding zones.
  • Special requirements may be necessary for swimming pools for medical use.
summary of the additional supplementary requirements placed by section 602 of bs 7671

602

2

SUMMARY OF THE ADDITIONAL SUPPLEMENTARY REQUIREMENTS PLACED BY SECTION 602 OF BS 7671
  • The swimming pool and its surrounding

area is divided into three zones, A, B

and C.

slide21

602

2

Examples of zone dimensions (plan) with fixed partitions of height at least 2.5 m

1.5

Zone C

Dimensions in metres

r1= 2

r2= r1 - (s1 + s2)

r3= 3.5

r4= r3 - (s1 + s2)

r5= r3 - (s3 + s4)

r3

r1

2.0

Zone B

r2

s1

r4

Zone A

r4

r1

r1

s3

r3

r2

s2

s4

r5

zone A – IPX8 zone B – IPX5 – IPX4 – where water jets are not likely to be used for cleaningzone C – IPX2 – for indoor pools – IPX4 – for outdoor pools – IPX5 – where water jets are likely to be used for cleaning.

slide22

602

2

Fig 602A - Zone dimensions for swimming pools and paddling pools

1.5 m

1.5 m

2.5 m

Volume

Volume

Volume

Volume

2.5 m

zone C

zone B

zone B

zone C

Volume

zone A

Volume zone A

1.5 m

2.0 m

2.0 m

1.5 m

Volume zone A

Note: The dimensions are measured taking account of walls and fixed partitions

slide23

2

602

  • Local supplementary equipotential bonding is required in all three zones. Where there is a metal grid in the floor, it must be connected to the local supplementary bonding.
  • With permitted exceptions, in zones A and B the only protective measure against electric shock allowed is SELV at a nominal voltage not exceeding 12 volts a.c. rms or 30 volts d.c.
slide24

2

602

  • There are particular IP minimum requirements for the zones:

zone A – IPX8

zone B – IPX5

-IPX4 – where water jets are not likely to be used for cleaning

zone C – IPX2 – for indoor pools

- IPX4 – for outdoor pools

- IPX5 – where water jets are likely to be used for cleaning.

slide25

2

602

In zones A and B no surface metal conduit or trunking is allowed nor is the exposed metallic cable sheath of an armoured cable or an exposed earthing conductor.

slide26

2

602

  • In zones A and B there should be no switchgear, controlgear, or accessories including socket-outlets, with a permitted exception for socket-outlets (BS EN 60309-2) in smaller pools for cleaning purposes with RCD protection or supplied from a safety isolating transformer – see section 602.
  • In zone C socket-outlets are allowed provided they are protected by an RCD and are of an industrial type to BS 4343 or BS EN 60309-2.
electricity supply

602

2

electricity supply
  • A distributor may not provide a PME earthing terminal for an installation such as that of a swimming pool.
  • The installation designer may decide not to employ it because of the possibility of perceived electric shock within the installation or the possible danger from a broken PEN conductor.
  • IEE Guidance Note 5 recommends:

Where a swimming pool forms part of a residence, all metalwork and pipes supplying the pool should be connected to an earth electrode and segregated from the rest of the building. An RCD should then be used to protect the supplies to the pool area and the swimming pool installation treated as part of the TT system.

overview of hot air saunas

2

603

Overview of hot air saunas
  • The risks
  • Scope
  • Shock protection
  • The wiring
  • The zones
  • Heating elements
slide29

2

603

The risks

  • Increased risk of electric shock because of extremely high humidity, lack of clothing, reduced skin resistance and large contact areas
  • Very high temperatures in certain zones.

Scope of section 603

  • Applies only to those where the sauna equipment complies with BS EN 60335-2-53 : 1997 – Electric sauna heating appliances.
slide30

2

603

Shock protection

  • The requirements for protection against direct and indirect contact in saunas are similar to those for bathrooms and swimming pools.

The wiring

  • All wiring should be carried out in flexible cables or cords, having 180 °C rubber insulation, complying with BS 7919 : 2001, and using insulated wiring enclosures complying with general Class II requirements.
the zones31

603

2

The Zones
  • The zones are temperature zones, dimensioned down from the ceiling, up from the floor and around the sauna. This allows application of the zones whatever the size of the sauna cabin.
slide32

2

603

Heating elements

  • Heating elements incorporated in a sauna may absorb moisture and cause the operation of a 30 mA RCD, if installed.
  • If it is wished to install a 30 mA RCD, it is wise to check its suitability with the heating equipment manufacturer and that the elements installed are suitable forprotection by a 30 mA device.
overview of construction site installations

604

2

Overview of construction site installations
  • The risks
  • Scope
  • Supplies
  • Reduced low voltage
  • Isolation and switching
  • Protection against the weather and dust
  • Inspection and testing
the risks34

604

2

The Risks

The risk of electric shock is high on a

construction site because :

1. of the possibility of damage to cables and equipment

2. of the wide use of hand tools with trailing leads

3. of the accessibility of many extraneous-conductive- parts, which cannot practically be bonded

4. the works are generally open to the elements.

slide35

2

604

Scope

  • Section 604 applies to all sites of construction work including the repair or alteration of existing buildings and demolition work.

Supplies

  • May be difficult to satisfy the electricity distributors bonding requirements because of the large number of parts of the building works that are extraneous-conductive-parts a therefore PME earthing terminal may not be provided
  • Distributor may offer a TN-S supply to large sites requiring their own substation.
reduced low voltage supplies for construction sites

604

2

Reduced Low Voltage Supplies for Construction Sites

BS 7671 requires the use of reduced low voltage supplies for all portable equipment, small mobile plant and local lighting up to 2 kW.

110 V reduced low voltage supplies with the centre point of the secondary winding of the step-down transformer earthed, limit the voltage to earth to 55 volts for single-phase supplies and 63.5 volts to earth for three-phase equipment

Limiting the voltage to 55 or 63.5 volts between a live conductor and earth effectively eliminates the risk of dangerous electric shock to exposed-conductive-parts

isolation and switching

604

2

Isolation and Switching

Section 604 repeats emergency switching requirements of Section 463 that emergency switching shall be provided on the supply to all the equipment from which it may be necessary to disconnect all live conductors in order to remove a hazard.

The requirement is to provide emergency switching where there is a need to remove a hazard, and the switching requirement is for

disconnection of all live conductors, that is including the neutral.

Every circuit supplying equipment shall be fed from a distribution

assembly complying with BS EN 60439-4 and BS 4363.

slide38

2

604

Protection against the weather and dust

  • Equipment for external use must be at least IP44.

Inspection and testing

Fixed installation:

  • It is recommended that the maximum period between inspections of construction site installations is 3 months.
  • Fixed installation RCDs should additionally be tested daily (using the

integral test button). Should RCDs be used to protect portable

equipment they must be tested by the operative before each period

of use (using the integral test button) and by the responsible person

every 3 months (using an RCD tester).

overview of agricultural horticultural premises

605

2

Overview of Agricultural & Horticultural Premises
  • Scope
  • The risks
  • Electricity supplies
  • Protection against electric shock
  • Earth electrode resistances
  • Protection against fire
  • External influences
605 overview of agricultural horticultural premises
605 - Overview of Agricultural & Horticultural Premises

Scope

  • applies to all parts of fixed installations, (such as stables, chicken-houses houses, piggeries, feed-processing locations, lofts and storage areas for hay, straw and fertilizers).
  • the dwellings are excluded from the scope of this section.
605 overview of agricultural horticultural premises41
605 - Overview of Agricultural & Horticultural Premises
  • Risks:
  • general accessibility of extraneous-conductive-parts and impracticality of supplementary or main bonding such extraneous parts
  • Harsh environment - mechanical damage, exposure to the weather, corrosive effects - water, animal urine, etc
  • a mechanically hazardous area due to electromechanical
  • equipment, mills and mixers, and mechanical drives of all kinds
  • rodent damage - leading to fire risks
  • storage of flammable materials e.g. straw and grain.
overview of restrictive conductive locations

606

2

Overview of Restrictive Conductive Locations
  • The risks
  • Scope
  • The particular requirements
606 overview of restrictive conductive locations
606 - Overview of Restrictive Conductive Locations
  • includes boiler shells, cable gantries, small tunnels, metal sewers etc. constructed mainly of metallic or conductive parts and within it movement is restricted.
  • Risks - little opportunity to move away from the shock, Contact resistance is low due to high contact areas and perspiration, so that body currents are high and the risk of ventricular fibrillation is high
606 overview of restrictive conductive locations44
606 - Overview of Restrictive Conductive Locations

particular requirements:

Protection against indirect contact one of the following:

  • 1) SELV with insulation and/or barriers,
  • 2) automatic disconnection of supply augmented by supplementary bonding,
  • 3) electrical separation with only one item of equipment connected to each secondary winding,
  • 4) the use of Class II equipment further protected by a 30 mA RCD.
slide45

607

2

Overview of Earthing Requirements for the Installation of Equipment having high protective conductor currents
  • The risks
  • Scope
  • The particular requirements
slide46
Overview of Earthing Requirements for the Installation of Equipment having high protective conductor currents
  • Scope:
  • The requirements of this section apply to :
  • 1) equipment between the final circuit wiring and current-using
  • equipment where the protective conductor current exceeds 3.5 mA
  • 2) final circuits where the accumulated protective conductor current
  • is expected to exceed 10 mA.
slide47
Overview of Earthing Requirements for the Installation of Equipment having high protective conductor currents
  • The risk associated with final circuits with high protective conductor currents is that resulting from discontinuity of the protective conductor.
  • The more equipment that is connected to a circuit, the wider is spread the risk, and the greater is the hazard.
slide48
Overview of Earthing Requirements for the Installation of Equipment having high protective conductor currents
overview of caravans tents and caravan parks

608

2

Overview of caravans, tents and caravan parks
  • Section 608 is divided into two divisions.
  • Division one - Electrical Installations in caravans and motor caravans
  • Division two - Electrical installations in caravan parks
overview of caravans tents and caravan parks50
Overview of caravans, tents and caravan parks
  • The risks specifically associated with installations in caravans and motor caravans arise from :
  • i) Open circuit faults of the PEN conductor of PME supplies
  • ii) Incorrect polarity at the pitch supply point
  • iii) Inability to establish an equipotential zone external to the vehicle
  • iv) Possible loss of earthing due to long supply cable runs,
  • v) Vibration while the vehicle is moving causing faults within the caravan installation.
overview of caravans tents and caravan parks51
Overview of caravans, tents and caravan parks
  • Particular requirements to reduce the above risks include:
  • i) Prohibition of the connection of exposed- and extraneous-conductive-parts conductive-parts of a caravan or motor caravan to a PME terminal
  • ii) Additional protection by 30 mA RCDs in both the vehicle and the park installation. Double-pole isolating switch and final circuit cbs in the caravan or motor caravan
  • iii) Internal wiring by flexible or stranded cables of cross-sectional area 1.5 mm2 or greater. Additional cable supports. Segregation of low voltage and extra-low voltage circuits.
overview of highway power supplies street furniture and street located equipment

611

2

Overview of highway power supplies, street furniture and street located equipment
  • By definition, “highway power supplies” include the complete highway installation comprising distribution boards, final circuits and the street furniture.
overview of highway power supplies street furniture and street located equipment53
Overview of highway power supplies, street furnitureand street located equipment
  • Main points:
  • Protection against electric shock – street furniture doors.
  • Protection against indirect contact
  • Disconnection times
  • Isolation and switching
  • Identification of cables
slide54

Part 7

2

Inspection and Testing

  • Every installation must be inspected and tested during erection and on completion before being put into service.
  • Precautions shall be taken to avoid danger to persons and to avoid damage to property and installed equipment during inspection and testing.
  • If the inspection and tests are satisfactory, a signed Electrical Installation Certificate together with a Schedule of Inspections and a Schedule of Test Results are to be given to the person ordering the work.
slide55

2

Part 7

Testing

  • Testing must include the relevant tests from the following checklist.
  • When a test shows a failure to comply, the installation must be corrected. The test must then be repeated, as must any earlier test that could have been influenced by the failure.
  • Testing checklist:
  • (i) continuity of protective conductors (including main and supplementary equipotential bonding conductors) (ii) continuity of ring final circuit conductors including protective conductors (iii) insulation resistance (between live conductors and between each live conductor and earth)
slide56

2

Part 7

(iv) polarity; this includes checks that single-pole control and protective devices (e.g. switches, circuit-breakers, fuses) are connected in the phase conductor only, that bayonet and Edison-screw lampholders (except for E14 and E27 to BS EN 60238) have their outer contacts connected to the neutral conductor and that wiring has been correctly connected to socket-outlets and other accessories (v) earth electrode resistance (vi) earth fault loop impedance (vii) prospective fault current, if not determined by enquiry of the distributor (viii) functional testing (including RCDs and RCBOs).

slide57

2

Part 7

Tests should be carried out in the following sequence:

Before the supply is connected

(i) continuity of protective conductors, including main and supplementary bonding (ii) continuity of ring final circuit conductors, including protective conductors (iii) insulation resistance (iv) polarity (by continuity methods) (v) earth electrode resistance, when using an earth electrode resistance tester (see also vii).

With the supply is connected

(vi) re-check of polarity (vii) earth electrode resistance, when using a loop impedance tester (viii) earth fault loop impedance (ix) prospective fault current measurement, if not determined by enquiry of the distributor (x) functional testing.

part 7 inspection and testing
Part 7 Inspection and Testing
  • MINOR ELECTRICAL INSTALLATION WORKS CERTIFICATE
  • The Minor Works Certificate is intended to be used for additions and alterations to an installation that do not extend to the provision of a new circuit.
  • Examples include the addition of a socket-outlet or lighting point to an existing circuit, the relocation of a light switch etc.
  • This Certificate may also be used for the replacement of equipment such as accessories or luminaires, but not for the replacement of distribution boards or similar items.
  • Appropriate inspection and testing, however, should always be carried out irrespective of the extent of the work undertaken.
part 7 inspection and testing59
Part 7 Inspection and Testing

ALTERATIONS AND ADDITIONS

  • Whilst there is no obligation to inspect and test any part of the existing installation that does not affect and is not affected by the alteration or addition, observed departures are required to be noted
part 7 inspection and testing61
Part 7 Inspection and Testing

THE ELECTRICAL INSTALLATION CERTIFICATE

  • The Electrical Installation Certificate is to be used only for the initial certification of a new installation or for

an alteration or addition to an existing installation where new circuits have been introduced

  • The original Certificate is to be given to the person ordering the work (Regulation 742-01-03). A duplicate should be retained by the contractor.
part 7 inspection and testing64
Part 7 Inspection and Testing

PERIODIC INSPECTION REPORT

  • This Periodic Inspection Report form shall only be used for the reporting on the condition of an existing installation.
  • The recommendation(s), if any, shall be categorised using the numbered coding 1-4 as appropriate.
part 7 inspection and testing65
Part 7 Inspection and Testing

periodic inspection report - observations and recommendations.

  • Within the observation and recommendations section each observation is required to be allocated a number as follows:
  • (1) Requires urgent attention
  • (2) Requires improvement
  • (3) Requires further investigation
  • (4) Does not comply with BS 7671, 2001 amended to (date). This does not imply the
  • electrical installation is unsafe.
3 the future 17 th edition

3

  • The 17th edition will be completely restructured compared to the present 16th Edition
  • The new edition will adopt the IEC numbering system

3. The Future – 17th Edition

slide67

3

  • In addition the layout and parts will be completely revised.
  • There will be a complete new chapter 41 and the current part 6 (special locations) will become part 7 to align with IEC.
  • The next edition of BS 7671 will include additional sections on special locations not currently included in BS 7671 as follows:
  • - Marinas - Photovoltaic power systems - Exhibitions, shows and stands - Floor and ceiling heating systems - Mobile and transportable units
  • - Fairgrounds, amusement parks and circuses
slide68

3

  • Examples of the increased risk in some of the special locations are given below:
  • Marinas
  • The water, salt, and movement of structures accelerate deterioration of the installation. The presence of salt water, dissimilar metals and a potential for leakage currents increases the rate of corrosion.
  • Increased electric shock risks associated with a wet environment, by reduction in body resistance and contact with earth potential.
slide69

3

  • Risks specifically associated with craft supplied from marinas include:
  • i) Open circuit faults of the PEN conductor of PME supplies raising the potential to true earth of all metalwork (including that of the craft, if connected) to dangerous levels
  • ii) Inability to establish an equipotential zone external to the craft
  • iii) Possible loss of earthing due to long supply cable runs, connecting devices exposed to weather and flexible cord connections liable to mechanical damage.
  • Particular requirements to reduce the above risks include:
  • i) Prohibition of the connection of exposed- and extraneous-conductive-parts of the craft to a PME terminal
  • ii) Additional protection by 30 mA RCDs in both the craft and the marina installation.
slide70

3

Typical wiring arrangement from shore to pontoon

  • Where the particular feeder pillars are in external locations they should be constructed of glass reinforced plastic (GRP), or have GRP housings. GRP is preferred to galvanised steel for protection against corrosion in such environments.
  • In order to counteract condensation within feeder pillar enclosures low wattage ‘anti‑condensation’ heaters should be installed.
  • All feeder pillar and distribution board doors should be fitted with locks to prevent unauthorised access, and have intermediate barriers to protect against accidental contact with live parts when the doors are open. The barriers should provide a degree of protection of at least IP2X or IPXXB.
slide71

3

Exhibitions

  • Risks associated with exhibitions, shows and stands are those of electric shock and fire. These arise from:
  • i) the temporary nature of the installation
  • ii) lack of permanent structures
  • iii) severe mechanical stresses
  • iv) access to the general public.
  • Because of these increased risks additional measures are required.
  • Regulation 21 of the ESQC Regulations has requirements for switched alternative sources of energy.
slide72

3

Exhibition/show distribution with standby generator

slide73

3

Ceiling Heating Systems

  • Risks associated with ceiling heating systems are generally that of penetration of the heating element by nails, drawing pins, etc pushed through the ceiling surface. For this reason supplementary protection against direct contact is required by the use of a 30 mA RCD.
  • Under floor heating installations can be damaged by carpet gripper nails, etc and for similar reasons protection by a 30 mA RCD or electrical separation is required.
  • To protect the building structure and provide precautions against fire, there are requirements to avoid overheating of the floor or ceiling heating system.
slide74

3

Future changes in the 17th Edition

for Special Locations

  • The current special locations contained in the IEE Wiring Regulations will be revised to align with the latest IEC and CENELEC standards.
  • For example the requirements for locations containing a bath or a shower unit will require RCD protection on all circuits in a bathroom/shower room.
  • The requirements for swimming pools will include fountains.
slide75

3

Example of determination of the zones of a fountain

slide76

3

  • The UK have retained the use of reduced low voltage supplies for construction sites which will continue to be a requirement in the 17th edition. Limiting the voltage to 55 or 63.5 volts between a live conductor and earth effectively eliminates the risk of dangerous electric shock to exposed-conductive-parts.

Reduced Low Voltage Supplies for Construction Sites

conclusion

3

  • We have come a long way in over 100 years,From:4 pages and 21 Regulations
  • To 17th Edition:due 2008

CONCLUSION

slide78

3

Thank you for listening

and

have you

any questions?

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