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ABB Furse IET wiring regulations brochure

ABB Furse IET wiring regulations brochure
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ABB Furse IET wiring regulations brochure - 1

IET Wiring regulations BS 7671 18th edition Transient overvoltage protection

ABB Furse IET wiring regulations brochure - 2

— The IET Wiring Regulations require all new electrical system designs and installations, as well as alterations and additions to existing installations, to be assessed against transient overvoltage risk and, where necessary, protected using appropriate surge protection measures (in the form of Surge Protection Devices SPDs).

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— Transient overvoltage protection Introduction Based on the IEC 60364 series, the 18th Edition of BS 7671 Wiring regulations covers the electrical installation of buildings including the use of surge protection. The 18th Edition of BS 7671 applies to the design, erection and verification of electrical installations, and also to additions and alterations to existing installations. Existing installations that have been installed in accordance with earlier editions of BS 7671 may not comply with the 18th edition in every respect. This does not necessarily mean that they are unsafe for...

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— Transient overvoltage protection Safeguarding your electrical systems DAMAGE > 1.5 kV (L-PE/N-PE) DAMAGE Degradation Safe Operating Area Nominal system voltage (e.g. 230 V) Safe Operating Area Degradation > 2x peak operating voltage (e.g. 715 V L-N) — Why is transient overvoltage protection so important? Transient overvoltages are short duration surges in voltage between two or more conductors (L-PE, L-N or N-PE), which can reach up to 6 kV on 230 Vac power lines, and generally result from: • Atmospheric origin (lightning activity through resistive or inductive coupling (see Figures 02 &...

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TRANSIENT OVERVOLTAGE PROTECTION - SAFEGUARDING YOUR ELECTRICAL SYSTEMS Serious injury to or Loss of safety services, Hospitals, care homes, Yes loss of human life medical care facilities home dialysis equipment Interruption of public services Loss of utility and IT services, Power stations, data centres, Yes and/or damage to cultural heritage damage to historic buildings heritage status buildings like museums, castles Interruption of commercial or Loss of electronic systems Banks, hotels, supermarkets, Yes industrial activity within service...

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IET WIRING REGULATIONS BS 7671 18TH EDITION Table 2 - Determination of fenv value based on environement (Table 443.1 BS 7671) Environment Definition Example fenv value Rural Area with a low density of Countryside 85 buildings Suburban Area with a medium density of Town outskirts 85 Urban Area with a high density of Town centre 850 buildings or densely populated communities with tall buildings Risk assessment length L_ 04 Lengths to consider P for the calculation of Lp The risk assessment length LP is calculated (Figure 443.3 BS 7671) as follows: Where: •...

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© Copyright 2018 ABB. All rights reserved. Specifications subject to change without notice. Argyll & Bute Perth & Kinross Scottish Borders Dumfries & Galloway North Yorkshire East Riding of Yorkshire 'West Yorkshire >outh Yorkshire [West Mids' Powys Herefordshire Lightning flash density Ng (flashes/km2/year) Key: (^) Use 0.1 Ng Use 0.3 Ng West Sussex East Sussex 05 UK lightning flash density map (Figure 443.1 BS 7671)

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ABB Furse IET wiring regulations brochure - 8

START Direct or nearby lightning strokes on the structure; or structures with risk of explosion; or where the damage may also involve the environment (e.g. chemical or radioactive) (443.1.1) Protection against overvoltages required – selected and installed to Section 534 Where the structure is equipped with an external lightning protection system LPS or protection against the effects of direct lightning on overhead lines Type 1 SPDs shall be installed as close as possible to the origin of the electrical installation (534.4.1.3). Consequences caused by overvoltage leads to: a) Serious injury...

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ABB Furse IET wiring regulations brochure - 9

EXAMPLES OF CALCULATED RISK LEVEL CRL FOR THE USE OF SPDS 06 Risk assement SPD decision flow chart for installations within the scope of this BS 7671 18th Edition. Examples of calculated risk level CRL for the use of SPDs (BS 7671 informative Annex A443). Example 1 - Building in rural environment in Notts with power supplied by overhead lines of which 0.4 km is LV line and 0.6 km is HV line Ground flash density Ng for central Notts = 1 (from Figure 05 UK flash density map). Environmental factor fenv = 85 (for rural environment - see Table 2) Risk assessment length LP LP _ 2 Lpal + Lpcl +...

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ABB Furse IET wiring regulations brochure - 10

IET WIRING REGULATIONS BS 7671 18TH EDITION Selection of SPDs to BS 7671 The scope of Section 534 of BS 7671 is to achieve overvoltage limitation within AC power systems to obtain insulation co-ordination, in line with Section 443, and other standards, including BS EN 62305-4. Overvoltage limitiation is achieved through installation of SPDs as per the recommendations in Section 534 (for AC power systems), and BS EN 62305-4 (for other power and data, signal or telecommunications lines). Selection of SPDs should achieve the limitation of transient overvoltages of atmospheric origin, and...

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Service entrance/ Main distribution board L1 Sub-distribution board Terminal equipment OCPD Risk of switching transient L1 ESP 415/I/TNS Enhanced Mains Protector Enhanced Mains Protector limp = 25kA/mode lmax = 100kA/mode ln = 25kA/mode Uc = 320VAC Up < 1.4kV Ures(limp) < 1.3kV ESP 415 D1/LCD Full Mode Type 1+2+3 SPD Critical equipment (e.g. hospital equipment) Main earthing terminal ESP 415/I/TNS with Type 1 performance installed at service entrance to divert high energy lightning currents to earth, and remove risk of flashover. OCPD: Overcurrent protective device (eg. fuse MCB) ESP 415...

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IET WIRING REGULATIONS BS 7671 18TH EDITION superior voltage protection levels (enhanced to BS EN 62305) between all conductors or modes. The active status indication informs the user of: • Loss of power • Loss of phase • Excessive N-E voltage status can also be monitored remotely via • Reduced protection the volt-free contact. ABB Furse ESP range of SPDs Enhanced solutions to BS EN 62305/BS 7671 The Furse ESP range of SPDs (power, data and telecom) are widely specified in all applications to ensure the continuous operation of critical electronic systems. They form part of a...

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ABB Furse IET wiring regulations brochure 20Pages

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ABB Furse IET wiring regulations brochure
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