iee wiring regulations
TRANSCRIPT
Dr Hani Obeid Assoc. Prof. EE, SMIEEE Consultant
Dr Hani Obeid
BiographyDr Hani Obeid received his MSc and PhD in power systems & networks fro Leningrad Polytechnic Institute (now St. Petersburg State Technical University) in 1974 and 1980 Respectively. From 1980 to 1983 worked in Jordan Electricity Authority. He started research in pollution of HV transmission line for the first time in Jordan. He designed the first 400 KV line in Jordan. From 1983- till now he is working as consultant and designer in electrical installations and architectural acoustics.Dr Hani Obeid 2
from 2000 till now he is an Assoc. Prof. EE/ Applied Sciences University. He is a senior member in IEEE. He is the author of the following books: . .( . ) .( . ) .( . . .( ) .( )Dr Hani Obeid 3
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The Wiring Regulations BS7671: currently 17th editionThe BS7671 Wiring Regulations is a non-statutory document, Which plays a key role in the electrical industry in terms of Standards and safety of electrical installation in buildings. The regulations provide guidance of the standards and the Latest 17th edition is effective from 1st of July 2008 and currently in implementation instead of the 16th edition.
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History of the Wiring Regulations1882 1st edition of the Wiring Rules issued. Entitled Rules & Regulations for the prevention of the fire Risks arising from electric lighting. 1888 2nd edition. 1897 3d edition entitled General Rules recommended for Wiring for the supply of Electrical Energy.Dr Hani Obeid 3
1903 4th Edition of the IEE Wiring Regulations, called Wiring Rules. 1907 5th Edition of the IEE Wiring Regulations. 1911 6th Edition of the IEE Wiring Regulations. 1916 7th Edition of the IEE Wiring Regulations. 1924 8th Edition of the IEE Wiring Regulations Regulations for the Electrical Equipment of Buildings. 1927 9th Edition of the IEE Wiring Regulations.
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1934 10th Edition of the IEE Wiring Regulations. 1939 11th Edition of the IEE Wiring Regulations, Revised issue (1943), reprinted with minor Amendments (1945), supplement issued (1946), Revised Section (1948). 1950 12th Edition of the IEE Wiring Regulations Launched, Supplement issued (1954). 1955 13th Edition of the IEE Wiring Regulations Launched, reprinted, 1958, 1961, 1962 and 1964.
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1966 14th Edition of the IEE Wiring Regulations published. Reprinted, 1968, 1969, 1970 (in Metric units), 1972, 1973, And 1976. 1981 the 15th Edition of the Wiring Regulations launched. 1991 16th Edition of the IEE Wiring Regulations published (adopted as the BS in 1992). Electricity at work regs. (Northern Ireland) come fully into being. 2004 Part P of the Building Regulations becomes law. BS 7671:2001 Requirements for the Electrical Installations (incorporating Amendments No.1:2002 and No.2:2004. The IEE Wiring Regulations 16th Edition.Dr Hani Obeid 8
2007 17th Edition of the IEE Wiring Regulations is Scheduled to be issued on January 1st 2008 and comes into effect 6 months later. It was actually available around 21st of January 2008. After July 1st 2008, designs must comply with the New 17th BS7671 wiring regulations.
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BS7871:1992 Requirements for Electrical Installations. IEE Wiring Regulations Sixteenth Edition
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BS7871:2008 Requirements for Electrical Installations. IEE Wiring Regulations Seventeenth Edition
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Standards
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The 17th Edition is the result of a complete review of the 16th Edition and aims to standardize the UK standards With the Harmonized Documents (HDs) produced By the European Committee for Electro technical Standardization (CENELEC).
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Contents of the 17th EditionRequirements for Electrical Installations IEE Wiring regulations BS7671: 2008 consists of 7 parts and 15 appendices.
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Title of the PartsPart 1: Scope, Object and Fundamental Principles. Part 2: Definitions. Part 3: Assessment of General Characteristics. Part 4: Protection of Safety. Part 5: Selection and Erection of Equipment. Part6: Inspection and Testing. Part 7: Special Installations or Locations.
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Appendices1. British Standards to which reference is made in the regulations. 2. Statutory regulations and associated memoranda. 3. Time/current characteristics of over-current protective devices and rcds. 4. Current-carrying capacity and voltage drop for cables and flexible cords. 5. Classification of external influence. 6. Model forms for certification and reporting.Dr Hani Obeid 16
7. Harmonized cable core colors. 8. Current-carrying capacity and voltage drop for bus bar trunking and power track systems. 9. Definitions-multiple source, d.c and other systems. 10. Protection of conductors in parallel against over current. 11. Effect of harmonic currents on balanced threephase systems.
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12. Voltage drop in consumers installations. 13. Methods for measuring the insulation resistance/impedance of floors and walls to earth or to the protective conductor system. 14. Measurement of earth fault loop impedance: consideration of the increase of the resistance of conductors with increase of temperature. 15. Ring and radial final circuit arrangements, regulation 433.1.Dr Hani Obeid 18
ChangesMany Changes were due to formal incorporation Of CENELEC drafts required to achieve Harmonization.
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CHANGES PREFACEA new informative note in the preface Advises that the publication of the 2008 edition of BS7671 does not automatically mean that installations Complying with previous editions are unsafe for continued Use or need to be upgraded.
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NUM ERING e e lati n n bers are c an ed s as t be in line issi n
it Internati nal lectr tec nical (I ) re bers.
is enables sers t readil relate r ean HDs and I re lati ns.
lati ns it
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FUNDAMENTAL PRINCIPLES. Requirements are added for protection for persons and livestock against Injury, and properly against damage by voltage Disturbances and electromagnetic influences.
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Chapter 13 Fundamental PrinciplesRegulation 131.6 adds requirements to protect against Voltage disturbances and implementation measures against electromagnetic influences. In doing so, the design shall take into consideration the anticipated Electromagnetic emissions generated by the installation Or the installed equipment, which shall be suitable For the current-using equipment used with, or connected To, the installation.Dr Hani Obeid 23
Regulation 132.13 requires that documentation for The electrical installation, including that required by Chapter 51, Part 6 and Part 7, is provided for Every Electrical installation.
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Chapter 35, Safety ServicesThis chapter recognizes the need for safety services, as these are frequently regulated by statutory authorities whose requirements have to be observed (e.g. emergency Escape lighting, fire alarm systems, installations for fire Pumps, fire rescue service lifts, smoke and heat Extraction equipment).
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Chapter 36, Continuity of servicesThis chapter requires that an assessment be made for Each circuit of any need for continuity of service Considered necessary during the intended life of The installation.
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CHAPTER 411. The chapter has been rewritten. Many regulations Are worded differently but the requirements are not Significantly changed. 2. The terms Direct Contact and Indirect Contact Are no longer used. They are replaced with Basic Protection and fault Protection.
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BASIC PROTECTIONProtection under normal conditions
is protection against touching live parts FAULT PROTECTIONProtection under fault conditions
is protection against receiving a shock from conductive parts that have been become live due to a breakdown of insulation or damage to equipment.
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3. Socket outlets rated not exceeding 20 A and intended for General use by ordinary persons must be protected with 30mA RCD. This means that general purpose sockets In domestic and similar properties must have RCD Protection. 4. External sockets not exceeding 32A must also have 30 mA RCD protection.
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5. Maximum permitted loop impedance - Z S Values have been adjusted, based on 230 V Nominal and this has slightly reduced these, For example for 32 A type B mcb the maximum Permitted is 1.44 ohms and was previously 1.5 ohms.Tables 41B1, 41B2, and 41D have been replaced by tables 41.2, 41.3, and 41.4
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RCDs should have a rated residual operating Current not exceeding 30mA and an operating time not exceeding 40ms at a residual current of five times the rated residual operating current. Chapter 41 includes a new table 41.5, which gives Maximum values of earth fault loop impedance For RCD to BS EN 61008-1 and BS EN 61009-1. This chapter includes the UK reduced low voltage system. Regulation 411.7 recognizes FELV as Measure a protectiveDr Hani Obeid 31
Chapter 42 Precautions where particular risks of fire existthe protection against thermal effects, includes Requirements in section 422 Precautions where particular risks of fire exist (These requirements Were previously stated in Section 482 of BS 7671:2001.
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Chapter 43 Protection against Over-currentthis includes those requirements previously given in Section 473 of BS7671:2001. Information on the over current protection of Conductors in parallel is given in Appendix 10.
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Chapter 44 Protection against voltage disturbanceThis includes a new section 422, covering the Protection of low voltage installations against Temporary over-voltages, due to earth faults in The high voltage system and faults in the low voltage system.
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This new section provides for the safety of the Low voltage system under fault conditions, Including faults in the high voltage system, Loss of the supply neutral in the low voltage System and short circuit between a line conductor And neutral in the low voltage installation.
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Section 443Section 443 on the protection of over-voltages of atmospheric origin, or due to switching, retains the Existing text from BS 7671. it also adds regulations Enabling designers to use a risk assessment approach When designing installations which may be susceptible To over-voltages of atmospheric origin.
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Chapter 52 Selection and erection of Wiring SystemsThis now includes bus-bars trunking systems and power track systems. Cables concealed in a wall or partition (at a depth of less than 50 mm) now need to be Protected by a 30 mA RCD, where the installations is Not intended to be under the supervision od a skilled or Instructed person, if the normal methods of protection Cannot be employed.
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Table 52.2, concerning cables surrounding by thermal insulation, gives slightly reduced de-rating factors, to take account of the availability of material with Improved thermal insulation.
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Chapter 53 Protection, Isolation, Control & MonitoringSimplification means that requirements previously In chapter 46, section 476 and 537 of BS7671:2001 are now covered in this single chapter. Chapter 53 also includes a new Section 532, Devices For Protection against the Risk of Fire, and a new Section 538 on Monitoring Devices.
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Chapter 54 Earthing Arrangements and Protective ConductorsThe requirement that a metallic pipe of a water utility Supply shall not be used as an earth electrode is retained in Regulation 542.2.4, which also states that other Metallic water supply pipe-work shall not be used as An earth electrode, unless precautions are taken against Its removal and has been considered for such a use.
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Regulation 543.7 has earthing requirements for the installation of equipment with high protective Conductor currents, previously in Section 607 of BS 7671:2001
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Chapter 55 Other EquipmentThis includes new additional requirements in Regulation 551.7 to ensure the safe connection of low voltage generating sets including small-scale Embedded generators (SSEGs).
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Chapter 56 Safety ServicesThis chapter has been expanded in line with IEC Standardization.
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Part 7 Special Installations or LocationsThis part includes the following changes: Section 607 in BS 7671:2001 relating to high Protective conductor currents has been incorporated Into Chapter 54.
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Section 608 in BS 7671:2001 has been incorporated into Section 708, Electrical Installations in Caravan/camping Parks and Similar Locations and Section 721, Electrical Installations in Caravans and Motor Caravans.
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The following Major Changes are Incorporated in Part 7
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Section 702 Swimming Pools and Other BasinsThis special location now includes basins of fountains. Zones A, B, and C in BS 7671:2001 are replaced by 0,1, and 2.
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Section 703 Rooms and Cabins Containing Sauna HeatersZones A, B, C, and D in BS 7671:2001 are Replaced by zones 1,2,and 3 (with changed Dimensions).
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Section 704 Construction and Dimension SiteThe reduced disconnection times (0.2s) And the 25 V equation no longer appear
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Section 705 Agricultural and Horticultural PremisesThe reduced disconnection times (0.2s) and the 25V equation no longer appear. Additional requirements applicable to life support systems Are included.
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Section 706 Conducting Locations with Restricted Movement
This was previously Section 606 in BS 7671:2001
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Secti lectrical I stallati i ara a / a Si ilar cati s
i
ar s a
This w i clu es the require e ts that each I i i ual s c et- utlet ust be r i e with O er-curre t a R D r tecti .
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New Sections included in Part 7Section 709: Marines and similar locations. Section 711: Exhibitions, show and stands. Section 753: Floor and ceiling heating systems. Section 712: Solar photovoltaic (pv) power Supply systems. Section: 717: Mobile or transportable units.
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Section 721: Electrical installations in caravans and motor caravans this was previously in section 608 of BS 7671:2001. Section 740: Temporary electrical installations for structures, amusement devices and booths at fairgrounds, amusement parks and circuses.
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Wiring Colors
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Three-phase InstallationsFor three-phase cables the phase colors are brown, black And grey, instead of red, yellow, and blue, respectively And the neutral color is now blue instead of black. Again the protective color conductor is identified by the Color combination green- and yellow. Alternatively all three of the phase conductor cores May be colored brown and marked L1, L2, L3 at the terminationDr Hani Obeid 61
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