dehn surge protection · 2020. 5. 27. · tpn fit 952 401/406 spn fit 952 173/178 yellowline spds...
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DEHN Surge ProtectionSelection guide to meet the requirements of18th edition BS7671
www.dehn-international.comwww.dehn.co.uk
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Where is Surge Protection Required?
Paragraph 443.4 of the 18th edition states that “Protection against transient overvoltages shall be provided where the consequences caused by overvoltage:-
A) results in serious Injury to, or loss of, human life, or: B) results in interruption of public services and/or damage to cultural heritage, or: C) results in interruption of commercial or industrial activity, or: D) affects a large number of co-located individuals.
For all other cases, a risk assessment according to Regulation 443.5 shall be performed in order to determine if protection against transient overvoltage is required. If the risk assessment is not performed, the electrical installation shall be provided with protection, except for single dwellings where the total value of the installation therein does not justify such protection.”
BS7671 / 18th Edition of the Wiring Regulations
Changes to the requirement for surge protection in sections 443 and 534
When are the changes to BS7671,18th Edition Wiring Regulations coming into effect?
On the 1st July 2018, the UK’s wiring regulations (BS7671) will be amended and the 18th edition released.
The amendments in this edition will have an important impact on electrical installations as among the changes are updates that will now make surge protection devices (SPD’s) a requirement to be installed. Other changes will make additional SPD’s a requirement further downstream and they will also affect what type of SPD’s can be installed as per the Lightning Protection Zones (LPZ) concept. We have set out a basic guide to the amendments below to help raise awareness to these changes.
HES
LPZ 3
LPZ 2
LPZ 2
LPZ 2
LPZ 2
LPZ 0B
LPZ 0B
LPZ 1
LPZ 1
LPZ 1
LPZ 0A
MEB
equipotential bonding
air-termination system
metal supply line
shielding
lightning equipotential bondinglightning current arrester (type 1)
local equipotential bondingsurge arrester (type 2/3)
lightning protection zone
main earthing busbar
low-voltage supply system
information technology system
MEB
What surge protection is required?
If the structure has external lightning protection installed then SPD’s shall be fitted where the cables enter/leave the structure. These SPD’s shall be type 1 - See section 534.4.1.3 In all other cases fit type 2 SPD’s at the origin of the electrical installation or where cables cross zonal interfaces as in section 534.4.1.2.
Then in section 534.4.1.5 further type 2 or Type 3 SPDs shall be located in the fixed electrical installation, for example, in sub distribution boards or close to the equipment to be protected, to ensure the required voltage protection level is maintained throughout the installation.
The changes in section 534.4.5.1 introduces a new term (SPDA) or surge protection device assembly this focuses on the performance of the SPD circuit so that includes the connected OCPD and the cables. The standard emphasizes that high surge impulse current values, for example 12.5kA for type 1 SPD are not being de-rated by undersized OCPD for example a MCB rated at just 6kA. This same section looks at lower voltage protection levels achieved by built in fusing for example see note 2 in section 534.4.4.2 and the DEHN CI SPD range with integrated fuses.
Why is surge protection required?
Surge protection is increasingly important because:
• Technical devices are becoming more and more sensitive – i.e. they are easily damaged in case of surges. For example, LED lights have a lower voltage withstand than the old florescent fittings that they replaced.
• An increasing amount of expensive electronic and Information technology devices are now being used – i.e. device replacement and loss of service is costly.
• Instrument functions are becoming more dependent on online access – i.e. nothing works without a functioning infrastructure. For example, every connected home or smart home is dependent on a working router or modem.
Type 2 SPN SPDDEHNguard TNDG M TN 275Part No. 952 200
Type 2 TPN SPD with integrated fusesDEHNguardDG M TNS CI 275 FMPart No. DSP2PA415CI
DEHN has a range of SPDs installed in IP65 rated enclosures that feature clear lids to show status indication of the device. The DSP range also has the options of SPDs with integrated fusing and so satisfying the requirements of the 18th edition for SPDA or surge protection device assembly.
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Surge protection in BS7671 to the LPZ conceptsection 443.4 overvoltage controlStart position
Protection against transient overvoltage‘s shall be provided where the consequence caused by over voltage:
(a)
(b)
(c)
(d)
results in serious injury to, or loss of, human life, or
results in interuption of public services and/or damage to cultural heritage, or
results in interuption of commercial or industrial activity, or
affects a large number of colocated individuals.
If the above consequences are met Is there a Lightning Protection System to BSEN 62305?
Yes
Then determine level of protectionFollow LPZ concept in section 534 For LPL 1 to 4 For LPL 3 and 4 only
No
Fit type 1/2 SPD from LPZ 0 to 1SPD is surge protective deviceSPDA is a SPD with built in OCPD/ fusessection 534.4.4.2 refers
Part numbers shown without / with remote contacts
Then fit type 2 SPD at LPZ 1-2At further DBsSPDA is a SPD with built in OCPD/ fusessection 534.4.4.2 refers
TPN TN fit type 1/ 2951 400/405 SPDor 961 200/205 SPDASPN TN type 1 /2Contact DEHN
TPN TN type 1/ 2941 400/405or 961 200/205 SPDASPN TN type 1/ 2941 200/205
Fit Type 2 SPD at all further zonal interfacessee section 534.4.1.1 to 534.4.1.5
Then fit type 2 or type 3 SPD at LPZ 2-3Closer to the sensitive equipment
Fit Type 2 and/ or 3 SPD at further zonal interfacessee section 534.4.1.1 to 534.4.1.5
Type 2TPN fit 952 400/405SPN fit 952 200/205
Type 3TPN fit 953 400/405SPN fit 953 200/205
SPDTPN fit 952 400/405SPN fit 952 200/205
SPDATPN fit 952 401/406SPN fit 952 173/178
Yellowline SPDs for communication and datalines
922 400 for single linetelephone applications
907 400 for multipletelephone lines (LSA Strip)
929 121 for Ethernet,CAT5, CAT6 and PoE.
For applications not covered by those listed consequences use, risk assessment in 443.5to determine CRL and then start flow chart from same position. SPDs required if CRL<1000.
SPDs also required if the CRL is not calculated
Fit Type 2 SPD at all cables entering buildingsee section 534.4.1.1 to 534.4.1.5
address data cables /comms entering buildingYes No
Fit Type 2 SPD at all further DBsif last SPD is greater than 10m away
Type 2 SPDTPN fit 952 400/405SPN fit 952 200/205
Type 3 SPDTPN fit 953 400/405SPN fit 953 200/205
address data cables / comms entering building
SPDTPN fit 952 400/405SPN fit 952 200/205
SPDATPN fit 952 401/406SPN fit 952 173/178
Any further DBs?
Yellowline SPDs for TV and CCTV applications
909 706 five channel SPDfor satellite installations
909 711 for BNC video camerasand recording equipment
Fit Type 2 and/or 3 SPDif sensitive end load greater than 10m awaysee section 534.4.4.2
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Planning software for lightning protection systems
FREE In-house seminars catered to your
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You may find useful other services we provide:
company's requirements
This software facilitates many calculations required for the lightning protection system: Risk management, separation distance, length of the air-termination rods and earth electrodes.
We design lightning protection and earth-termination systems using 3D planning including drawings, mounting details, detailed descriptions, tender specifications and bills of material.
A series of ESSENTIAL in-house seminars for anyone involved in Surge and Lightning Protection.
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TYPE 1/2 combined Lightning and Surge arresters
DEHNventil® M TN 255 (951 200/205*)Modular combined lightning current and surge arrester for single-phase TN systems
DEHNventil® M TN 255 FM (951 400/405*)Modular combined lightning current and surge arrester for three-phase systems
* available with volt free contacts for remote monitoring
DEHNshield® DSH TN 255 (941 200/205*)Application-optimised and prewired combined lightning current and surge arrester for single-phase TN systems.
DEHNshield® DSH TNS 255 (941 400/405*)Application-optimised and prewired combined lightning current and surge arrester for TN-S systems.
* available with volt free contacts for remote monitoring
DEHNvenCI 1 255 (961 200)Type 1 combined arrester with integrated backup fuse
DEHNvenCI 1 255 FM (961 205)With remote signalling contact for control device (floating changeover contact)
DEHNvenCI (SPDA) Surge Protection Device Assembly
TYPE 2 Surge protection devices
DEHNguard® M TN 255 (952 200)Modular surge arrester for single-phase 230 V TN systems
DEHNguard® M TN 255 FM (952 205)With remote signalling contact for control device (floating changeover contact)
DEHNguard® M TNS 255 (952 400)Modular surge arrester for three-phase systems
DEHNguard® M TNS 255 FM (952 405)With remote signalling contact for control device (floating changeover contact)
DEHNguardCI (SPDA)
DEHNguard® CI 275 (952 173/178*)Modular surge arrester with integrated fuse for single-phase 230V TN sytems
DEHNguard® CI 275 (952 401/406*)Modular surge arrester with integrated fuse for three-phase sytems
* available with volt free contacts for remote monitoring
Meets requirements of integrated (SPDA) surge protection device assembly. SPDs for TT supplies In all the cases listed within the flowchart and listed above, there is a TT version of the SPD for TT supplies, please call DEHN UK office or refer to the DEHN website. This will ensure compliance to the requirements of the CT2 connection method in regulation 534.4.3.2
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DS301/UK/0818 © Copyright 2018 DEHN + SÖHNE
Tel. +44 1484 859 111Fax +44 1484 859 222info@dehn.co.ukwww.dehn.co.uk
Unit N8BMeltham MillsMelthamHolmfirth, HD9 4DS
DEHN (UK) LtdSurge ProtectionLightning ProtectionSafety EquipmentDEHN protects.
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For information on our registered trademarks, please visit www.dehn-international.com/en/our-registered-trademarks. We accept no liability for technical modifications, misprints and errors. Illustrations are not binding.
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