The basics of lightning and surge protection

Prevention is better than cureThe basics of lightning andsurge protectionThe standards also provide helpful support for users.IEC 61643-12 is valid for the installation of energy-protectioncomponents and IEC 61643-22 is valid when protectingmeasurement and control systems. IEC 62305 is the overallguideline for all applications when dealing with lightning andsurge protection. This standard covers all the parameters: riskanalysis, external and internal lightning protection.The subject of surge protection is rather complicated andrequires special knowledge. Therefore, this catalogue providesyou with some helpful information. And if you want to knowmore, simply contact us. We shall be happy to help and adviseyou.W1296380000 – 2012/2013W.3

The basics of lightning andsurge protectionWhat are overvoltages?What are overvoltages?Surges are extremely high voltages that damage or evencompletely destroy insulation and hence impair or completelydisrupt the function of electrical and electronic components of allkinds.Every electrical component is provided with insulation to isolatethe electrical voltage from earth or other voltage-carrying parts.The insulation strength is dependent on the rated voltage andthe type of electrical component, as stipulated by the IEC/VDEregulations. It is tested by applying the prescribed voltages for adefined period of time.If the test voltage is exceeded in operation, the safety effectof the insulation is no longer guaranteed. The component canbe damaged or completely ruined. Surges are the voltagepulses that are higher than the test voltage and therefore couldhave a detrimental effect on the respective electrical componentor system. This means that components with a high ratedvoltage may be capable of withstanding a surge voltage. Butcomponents with a lower rated voltage would be very much atrisk from the same surge. An overvoltage allowable in an electricmotor can spell disaster for an electronic circuit!Permanently higher voltages also occur with the 50/60 Hz mainsfrequency. These voltages can be coupled or may occur as aresult of faulty switching operations. The resulting continuousinterference voltages are then another case for overvoltageprotection.Individual surge pulses, which have a high frequency because oftheir physical formation, have a current rise that is about tenthousand times steeper compared with 50 Hz voltage. If thecurrent rise time in the 50/60 Hz range is 5 ms, then for anovervoltage it is around 1 µs.These surges are designated as “transient” voltages.This means that they are short-lived, temporary oscillations.Their shape and frequency depends on the impedance of thecircuit.Voltage in V25,00020,00015,00010,0005,00035030025020015010050Surge pulseRising edge of the surge pulse / mains voltageMains voltage 50 Hz00 1 2 3 4 5 5,000 10,000Time in µsEdge behaviour between a 50 Hz sine wave and surge pulseWW.41296380000 – 2012/2013

How do overvoltages occur?How do overvoltages occur?The basics of lightning andsurge protectionSurges are primarily caused by:• transient switching operations• lightning due to atmospheric discharges• electrostatic discharges• faulty switching operationsConductive couplingi 1i 2Z gLightningi gBolts of lightning exhibit extremely high currents. Therefore, theycause a large voltage drop and, accordingly, a large risein potential even in well earthed buildings or systems despitelow earthing resistances.This will then cause a galvanic, inductive or capacitive couplingof surge voltages within the circuits of electrical or electronicfacilities. It will also penetrate through the insulation.This means no electrical isolation methods provide reliableprotection against surge voltages. Analogue converters, relaysor opto modules are important for separating potentials, butthey are definitely not surge protection components.A natural lightning strike consists of a main discharge and atime shifted post discharge. The strength of this seconddischarge is usually far below the energy level of the maindischarge. Both discharges, however, have enough power tocause significant damage.In practice, lightning current generators have been developedwhich can simulate a lightning pulse.The various forms of coupling must be considered in order tounderstand the effects of lightning.Surges are transferred directly into circuits via common earthingimpedances. The magnitude of the overvoltage depends on theamperage of the lightning and the earthing conditions. Thefrequency and the wave behaviour are mainly determined by theinductance and the speed of the current rise. Even distantlightning strikes can lead to overvoltages in the form of travellingwaves, which affect different parts of electrical systems by wayof conductive couplingInductive couplingi SHi indA high-amperage lightning strike generates a strong magneticfield. Starting from here, overvoltages reach nearby circuits bymeans of an induction effect (e.g. directly earthed conductor,power supply lines, data lines, etc.). According to thetransformer principle, the coupling of induced voltages isconsiderable owing to the high-frequency current di/dt – evenwhen primary and secondary windings consist of only a singlewinding each, i.e. the inductance is low.I/kAMain dischargeCapacitive coupling--IimpPeriod between the dischargesand the several follow-updischargesC PC P00 10 20 30 40 50 60 70 80 90 t/µ 110C PThe discharge curve of natural lightning (red) and a simulatedlightning strike from lightning current generator (green)A capacitive coupling of overvoltages is also possible. The highvoltage of the lightning generates an electric field with a highW1296380000 – 2012/2013W.5

The basics of lightning andsurge protectionHow do overvoltages occur?field strength. The transport of electrons can cause a capacitivedecay to circuits with lower potentials and raise the potentialconcerned to an overvoltage level.example, electronic components, then these can be completelyruined. Special care is taken, for example, with ESD issueswhen manufacturing electronic circuit boards.Radiation couplingFaulty switching operationsE / HAgain and again, we experience faulty switching operationsin the 50/60 Hz mains. This can be caused by a failed powersupply unit controller or incorrect wiring in a panel. Therelatively high voltages that can occur as a result also representdangerous overvoltages. Protection against these is vital.Electromagnetic wave fields (E/H field), that also ensue duringlightning (distant field condition, E/H field vectors perpendicularto each other), affect conductor structures in such a way thatcoupled overvoltages must be expected even without directlightning strikes. Permanent wave fields from strong transmittersare also able to cause coupled interference voltages in lines andcircuits.Description of interference voltagesSurge voltages that occur between live conductors, or betweena live conductor and the neutral conductor, are called transversevoltage or symmetric interference [U Q ].i Si SU QWSwitching operations – transientsMore often, it is switching operations that cause interferencerather than lightning. High-amperage shutdowns in the mains inparticular can generate considerable overvoltages (e. g. weldingequipment). Switching operations generate overvoltagesbecause, due to their construction, switching contacts thatswitch the current on or off do not operate in synchronisationwith the current zero of an alternating current. This means thatin the majority of cases there is a very rapid change of current,from a high value to zero (di/dt). Owing to the impedances in thecircuit concerned, this leads to transient overvoltages with highfrequencyoscillations and high voltage peaks. These can reachelectrical components by conductive, inductive or capacitivemeans and endanger or damage them. The situation is similarin the case of short- circuits in the mains because these alsorepresent a rapid switching operation.Electrostatic discharges – ESDElectrostatic discharges (ESD) caused by frictional chargesare well known. You can experience them when getting outof a car or walking across a carpet. These discharges can beover 10,000 volts in strength. We speak of ESD when thesedischarge to a lower potential. If such a charge strikes, forSurge voltages that occur between a live conductor and thePE conductor are called longitudinal voltage or asymmetricinterference [U L ].i Si SUL U LThe forms of interference voltageCoupled transient surge voltages are basically either symmetric(differential-mode interference) or asymmetric (common-mode)interferences, which are measured as longitudinal or transversevoltages.Normal-mode interference (symmetrical interference)A voltage between supply and return conductor, differential modevoltage/current. Occurs mainly at low interference frequencies inthe existing lines. The interference current causes an interferencevoltage UQ directly at the interference sink (between the inputterminals). With galvanic or inductive coupling, both theeffective sources and the interference sources are connectedW.61296380000 – 2012/2013

How do overvoltages occur?The basics of lightning andsurge protectionserially. Series connection of load and interference source, e.g.in the case of inductive (magnetic field) or conductive coupling(common impedance).In symmetrical circuits (non-earthed or virtual potential earthed),the normal-mode interference occurs as symmetrical voltages.In unsymmetrical circuits (earthed one side), the normal-modeinterference occurs as unsymmetrical voltages.Transverse voltage U Q (normal-mode voltage)This is a transient coupled interference between two activeconductors. For asymmetric circuits with ground potential, thetransverse voltage is equal to the longitudinal voltage [U Q = U L ].A remedy or limitation may be achieved by twisting thecorresponding wires together and shielding or multiple shieldingwith cable sheath. This reduces the induction of transversevoltages.Common-mode interference (unsymmetrical interference)Voltage between conductor and reference potential (earth),common-mode voltage/current. Mainly caused by a capacitivecoupling (electrical field).Therefore, significant common-mode interference currents onlyflow at higher interference frequencies. The interference voltageat the potentially susceptible device is caused by differentvoltage drops at the supply and return conductors (in eachcase between input terminal and reference earth). Source ofinterference between signal wire and reference conductor, e.g.due to a capacitive coupling or an increase in reference potentialbetween separate earths.In symmetrical circuits, common-mode interference occurs asasymmetrical voltages between the d.c. offset of the circuit andthe reference earth. The forward and return conductors have thesame interference voltages compared to the referenceground. In unsymmetrical circuits, common-mode interferenceoccurs as unsymmetrical voltages between the individualconductors and the reference earth.long lines entering a building from the outside.ConsequencesThe impedances and stray capacitances are equal in idealcircuits. This means that the currents in the supply and returnconductors generated by coupled overvoltages are also equaland so do not generate any interference voltage.However, in practice the impedances and stray capacitancesin the supply and return conductors are different. This results inunequal currents which cause different voltages to earth in thesupply and return conductors.So the unequal impedances lead to the common-mode voltagebecoming, for the most part, a normal-mode voltage because ofthe dissimilarity in the voltages to earth of the supply and returnconductors.U push-pullElectrical systemU sym.Z / 2Z / 2SURGE PROTECTIONSURGE PROTECTIONSURGE PROTECTION01234MSR5U unbalanced 1U unbalanced 2Longitudinal voltage U L (common-mode voltage)U asym.U common modeCoupled transient interference voltage between an activeconductor and the earth potential. As a rule, the longitudinalvoltage is higher than the transverse voltage (transverse voltageis lower owing to cable shielding and twisting).Longitudinal voltages caused by lightning currents on cableshielding can assume quite high values, especially in the case ofW1296380000 – 2012/2013W.7

The basics of lightning andsurge protectionHow do we achieve surge protection?How do we achieve surge protection?We have to consider surge protection from two points of view:• General protective measures during the planning andconstruction of buildings and electrical installations.• Special protective measures realised by the installation ofadditional surge protection components.Planning buildings and electrical installationsSome significant measures to prevent or limit surge voltagedamages can be incorporated into buildings and electrical/electronic facilities right from the start. Although such measurescan achieve only basic protection, they do save some of thecosts for an effective, complete protection concept. Beginningwith the first phase of construction, it is very important to setup an earthing or equipotential bonding facility of sufficient size.Only this will ensure full equipotential bonding in the event of amalfunction.Thus when speaking of lightning protection, we only referto lightning protection equipotential bonding. All cables areconnected to the lightning protection equipotential bonding:including the power supply, measurement and control signals,telephone lines, and even the water and gas lines.When planning the electrical installation, care must be taken toensure that electrical systems with dissimilar rated voltages arekept separate. Corresponding protection zones can then be setup and this leads to cost-savings for the surge protection.Furthermore, the physical separation or shielding of lines thatcan influence each other is a good way to achieve maximumelectrical isolation. Another good option is to split up theindividual phases of three-phase systems corresponding to theirfunctions, e.g. one phase only for the supply to instrumentationand control systems.has been reached, and quench the overvoltage. The responsetime lies in the nanoseconds range.Naturally the surge protection components must be able towithstand very high currents, since a surge can, under certaincircumstances, deliver several thousand amperes. At the sametime, no excessive (i.e., dangerous) residual voltages shouldremain, even if the operating current is very high. So surgeprotection components must exhibit a very low resistancedischarge behaviour.Apart from that, it is absolutely essential that the surgeprotection component is very quickly available again in electricalterms after the surge has been quenched by earthing it.This is necessary to ensure that the function of the circuit isguaranteed.Good surge protection is characterised by:• fast response behaviour• high current-carrying capacity• low residual voltage• good reactivation timeWOf course, all these primary measures do not achieve completeprotection. To do this, you must install additional protectivecomponents.Surge protection componentsSurge voltages are kept away from at-risk electrical componentsby first reducing them to a harmless dimension before theyreach the components.The quick reaction times of surge arresters are used to providethis protection. They must respond during the high-frequencyrising phase of the overvoltage, i.e. before a dangerous valueWeidmüller can supply protective components that fulfil thesecriteria. Depending on the application, these usually consist of acombination of individual components, as described in thechapter on surge components. Which combination of protectivecomponents is available for the respective application isdescribed in the chapters B, C and D.Furthermore, it becomes clearer, from the set-up of theprotective elements, how and where a product is used. Thefirst protection mechanism is always installed at the buildingentrance, so that the initial coupling interference can be directly“intercepted” before the sensitive end devices.W.81296380000 – 2012/2013

Surge protection conceptSurge protection conceptThe basics of lightning andsurge protectionElectrical systemSURGE PROTECTIONSURGE PROTECTIONSURGE PROTECTION01234MSR5A fundamental requirement for effective surge protection isthe presence of properly functioning equipotential bonding toDIN VDE 0100 part 540 in a series, or better still, star or gridarrangement.DIN VDE 0110 (insulation coordination) divides overvoltageprotection for power supplies and power distribution into thefollowing three areas:1. Power supplyThe surge voltage strength of the insulation is 6 kV from theincoming supply to the building – by means of undergroundcables or overhead lines – right up to the main distributionboard (backup fuse and meter cupboard). Owing to the lightningprotection zoning concept and the physical circumstances,high-energy overvoltages have to be discharged here.Fundamental concept of protectionOne important aspect of surge protection is the area of powersupply and distribution. The procedure is linked to thesystematic subdivision prescribed by the protective zonesconcept and the corresponding coordination of surge arresters.Protection of power supply lines forms the basis for protectingall electrical and electronic equipment right down to the smallestand most sensitive components.Surge currents exceeding 200 kA can be generated bycloud-to-ground but also cloud-to-cloud lightning discharges.As a rule, 50 % of the current is discharged via the lightningprotection system and the remaining 50 % is coupled into theconductors and conductive parts in the building and distributeduniformly. The closer a conductor is to the lightning protectionsystem, the greater is the launched voltage (which can exceed100 kV). The pulse duration can be up to 0.5 m s. Thesepowerful interference pulses are discharged to earth directlyat the incoming supply or main distribution board by class Ilightning arresters and limited to voltages below 6 kV. Powerfollow currents and backup fuse values are just some of theaspects that need to be taken into account here.Depending on the local circumstances and the dischargecurrents to be expected, sparkover gaps or varistor surgeW1296380000 – 2012/2013W.9

The basics of lightning andsurge protectionSurge protection conceptarresters are used, taking into account the type of network.If a lightning protection system has been installed, or the powersupply is via overhead lines, or buildings or plants are spreadover a wide area and individual buildings are sited on elevatedground or open areas, high-capacity class I arresters shouldalways be employed.2. SubdistributionThe surge voltage strength of the insulation is 4 kV from themain distribution board up to and including subdistributionboards. Owing to the coordinated use of arresters, class II surgearresters are used here and, if necessary, decoupled from classI arresters by means of coils. The use of decoupling coils is onlynecessary when the class I arresters consist of one sparkovergap and the length of the line between the class I and classII arresters is less than 10 m. It is not necessary to decoupleWeidmüller class I and class II arresters. The pulse currentsthat occur here are no longer that high because most of theenergy has already been absorbed by the class I arresters.Nevertheless, the line impedances giverise to high interference voltages which must be limited to lessthan 4 kV by the class II arresters. Class II arresters based onvaristors are normally installed in the sub distribution boardbefore the residual-current circuit-breakers.3. Terminals, consumers, socketsThe surge voltage strength of the insulation is 2.5 kV from thesubdistribution board to the electrical consumer. Surge arrestersin Class III are used for this purpose. Depending on theapplication, they can be used as protective components or incomposite switching together with gas discharge tubes,varistors, suppressor diodes and decoupling elements. Thesearresters are best installed directly before the device to beprotected. This can be in a socket or trailing socket (onextension lead) but also in the terminal or junction box of thedevice itself.To protect against permanent interference such as “ripples” or“noise” caused by other systems, additional filter circuits areavailable for the voltage supplies to devices. The insulation ofthe electrical consumer itself has a surge voltage strength of1.5 kV.Principle for selecting arresters according to IEC 664 DIN VDE 0110 part 1WW.101296380000 – 2012/2013

Classification and protective zonesClassification and protective zonesThe basics of lightning andsurge protectionThe requirements placed on surge protection and the necessarytests for surge protection components are stipulated by nationaland international standards. A product can only be consideredsafe after the product has been fully tested.For rated voltages up to 1000 V AC, the standards arevalid for the manufacturers of surge protection devicesand the installers of the surge protection within thefacility or system. This catalogue contains a list of validstandards for your reference.The insulation coordination for electrical equipment in lowvoltagesystems to IIIV EN 60664-1 (IEC 60664-1) is critical forthe design of surge protection. This specifies different dielectricstrengths within electrical systems. Based on this, individuallightning protection zones can be set up according toIEC/EN 62305-3.Lightning protection zonesA protective zone is characterised by a fully earthed envelope.In other words, it has an enclosing shield which enables fullequipotential bonding. This shielding can also be formed bybuilding materials such as metal facades or metal reinforcement.Lines that pass through this shield must be protected witharresters in such a way that a prescribed protection level isachieved. Further protective zones can be set up inside such aprotective zone. The protection level of these zones can belower than that of the enclosing protective zone.This leads to a coordinated protection level for the objects to beprotected. Not every individual section has to be protected withthe maximum protection level (e.g. against lightning). Instead,the individual protective zones guarantee that a certainovervoltage level is not exceeded and hence cannot infiltratethat zone.This leads to economic protection concepts with respect to thecapital outlay for protective components.ClassificationOriginally, protective zones were classified according to coarse,medium and fine protection. These protective zones weredesignated classes B, C and D in IEC 60099 (VDE 0675-1).There was also a class A for external arresters (e.g. for lowvoltageoverhead lines); however, this class has now beenabolished. The IEC 61643-1:2011 classifies the protective zonesas classes I, II and III.Comparison of surge protection classifications.Many national standards, e.g. in Austria, are derived fromthe aforementioned VDE or IEC standards.FormerlyDIN VDE 0675 Teil 6 / A1Arresters of requirements class B, lightningprotection equipotential bonding to DIN VDE0185 part 1 (“B arresters”)Arresters of requirements class C, surgeprotection in permanent installations, surgewithstand voltage category (surge cat.) III(“C arresters”)NewIEC 61 643-1“Class I” arresters“Class II” arrestersArresters of requirements class D, surgeprotection in mobile/permanent installations,surge withstand voltage category(surge cat.) II (“D arresters”)“Class III” arrestersWeidmüller makes sure that all our surge protection productsare tested by an independent testing lab for compliance with therelevant product standards. This is documented by test reportsand corresponding test certificates.W1296380000 – 2012/2013W.11

The basics of lightning andsurge protectionLightning protection levelsSchutzklasseLightning protection level (LPL)The lightning protection level applies only to the pulsecurrent 10/350 or to the class I.I200 kALightning protection level I100 kAPAS100 kALightning protection level I covers a pulse of 200 kA. This is theworst-case scenario of a direct strike. This pertains to externallightning protection facilities.Half of this pulse is conducted to the earth and the other half isconducted to the section of the facility that is conductive.If only a four-wire system is available, then a current of 25 kA isdistributed to each wire. For a five-wire system, that wouldcorrespond to 20 kA.This lightning protection class covers multiple areas, including:petrochemical facilities (Ex-zones) and explosive materialdepots.II150 kALightning protection level II75 kA75 kAPASLightning protection level II covers a pulse of 150 kA. Thispertains to external lightning protection facilities. Half of thispulse is conducted to the earth and the other half is conductedto that section of the facility that is conductive.If only a four-wire system is available, then a current of 19 kA isdistributed to each wire. For a five-wire system, that wouldcorrespond to 15 kA.This lightning protection class covers multiple areas, including:parts of hospitals, shipping warehouses and telecommunicationtowers.III/IV100 kALightning protection level III/IVW50 kA50 kAPASLightning protection level III covers a pulse of 100 kA. Thispertains to external lightning protection facilities. Half of this pulseis conducted to the earth and the other half is conducted to thatsection of the facility that is conductive.If only a four-wire system is available, then a current of 12.5 kA isdistributed to each wire. For a five-wire system, thatcalculates to 10 kA. The 12.5 kA value is also used here.About 80% of all applications are covered by lightningprotection class III. This includes houses, home, administrativebuildings and industrial facilities.W.121296380000 – 2012/2013

Table 2.2.1Buildings requiring lightning protection, lightning protection levels, control intervalsBuilding, facility, zone, areasa Buildings that have rooms with a large number of occupants (e.g. theatres, concert halls, dancehalls, cinemas, multi-purpose sporting/exhibition arenas, retail stores, restaurants, churches, schools,transportation facilities such as railway stations and similar sites of public assembly, including theassociated buildings, which can be adversely affected by a lightning strike);NoteEspecially multi-purpose sports/exhibition arenas, theatres, cinemas, restaurants and similar sites with roomswhere there could be 100 or more persons; sales sites with a total sales area of less than 1,200 m 2 , if thecalculated number exceeds 100 persons, sales sites with a total sales area of more than 1,200 m 2 .b Accommodation facilities (e.g. hotels, nursing homes, institutions, hospitals, prisons, military barracks);NoteEspecially hospitals, nursing homes where there are permanently or temporarily 10 or more persons whodepend on outside help; especially hotels, inns and boarding houses where there are permanently ortemporarily 15 or more persons that do not depend on outside help.c Particularly tall buildings, including the adjoining buildings of normal height;high-rise buildings used as residential and commercial buildings,high chimneys and towers (church steeples).NoteBuildings which are considered tall according to building legislation or where the top floor is more than22 metres above the surrounding terrain serviced by firemen or where the eaves have a height of more than25 metres..d Buildings made from combustible materials with a total volume of more than 3,000 m³;e Large agricultural and operational buildings (more than 3,000 m³) including the adjoining silos andadjacent residential buildings which could be adversely affected by a lightning strike;fermenting facilities or biogas plants;f Industrial and commercial buildings in high-risk areas (such as plants and equipment where flammable orexplosive materials are handled or stored), wood processing factories, mills, chemical plants, textile andplastics factories, explosives and ammunition depots, pipelines, gas stations;– Areas at risk of fire– Explosive-risk zones under a roofg Containers for flammable or explosive substances (such as flammable liquids or gases), warehouses forsolid or liquid fuels and associated buildings and facilities (e.g. machine buildings, gas stations, storagebuildings with filling equipment);h Buildings and facilities which house content that has a special value (e.g. archives, museums, collections);i Buildings and facilities which house sensitive technical equipment (e.g. IT and telecommunicationsfacilities);Data centres;j Buildings and installations in exposed topographic positions(e.g. free-standing building [alpine huts] in the mountains)Lightning protection levelIIIIIIIIIIIIIIIII – IIIIIIIIIII – IGuidelines SEV 4022Control intervals (years)10101010101010 – 3103101010 – 3The basics of lightning andsurge protectionExtract from the guidelines of the SEV 4022 Lightning Protection Systems 2008; please follow the installation regulations and standards in the individual countries.W1296380000 – 2012/2013W.13

The basics of lightning andsurge protectionNetwork formsNetwork forms to DIN VDE 0100 part 300(DIN 57100 part 310)The letters describe the earthing conditions1st letterEarthing at current source2nd letterEarthing of exposed conductiveparts of electrical installation3rd letterRouting of N and PE conductor(only applies to TN systems)T-Direct earthing of current source(of transformer)I-Insulated structure of current sourceT-Exposed conductive parts of electricalinstallation are earthed directlyN-Exposed conductive parts ofelectrical installation are connected toearth of current sourceC-“Combined” N conductor and PEconductor are routed together as PENconductor from current source intoelectrical installationS-“Separate” N conductor and PE conductorare routed separately from current sourceto exposed conductive parts of electricalinstallationFour-conductor systems:Still valid according to VDE but unfavourable for informationtechnology systems from the point of view of EMC (VDE 0100 pt444 / pt 540 pt 2).TN-C-System (“classic earthing”)Neutral conductor and protective earth conductor functions arecombined throughout the network in a single conductor, thePEN conductor.TN-C-S-System (“modern earthing”)Neutral conductor, PEN conductor and equipotential bondingsystem are connected once at the main distribution board orafter the incoming supply to the building. Therefore, aTN-C system becomes a TN-S system (TN-C-S system) fromthis point onwards.WW.141296380000 – 2012/2013

Network formsThe basics of lightning andsurge protectionFive-conductor systems:The neutral point of the supply source is earthed (N and PE).Both conductors must be laid separately and insulated from theincoming supply onwards. In these systems the PE (protectiveearth conductor ) does not carry any operating current butinstead only discharge currents.TN-S systemsNeutral conductor and protective earth conductor are separatedthroughout the network.TT systemsOne point is earthed directly (operational earth). The exposedconductive parts of the electrical installation are connected toearth lines separate from the operational earthSpecial system:Used, for example, in medical applicationsIT systemsThere is no direct connection between active conductors andearthed parts. The exposed conductive parts of the electricalinstallation are earthed.W1296380000 – 2012/2013W.15

3+1 circuit: universal solutionThe basics of lightning andsurge protectionprotection against hazardous touch voltages in all situations.In terms of its relevance for safety aspects, the 3+1 circuitdescribed in VDE 0100 part 534 (section 534.2.2) can thereforebe regarded as a solution for surge protection in TT systems.Note: Although the “four-arrester circuit”, i.e. with one varistoreach between earth potential and L1, L2, L3 and N, isprescribed in VDE 0100 part 534 (section 524.2.1) forconsumer installations in TN-S systems, the 3+1 circuit wouldalso be possible here without increasing the risk.In ÖVE/ÖNORM E 8001-1/A2:2003-11-01, the 3+1 circuit isalready expressly listed for use in TN-S and TT systems.TT systemW1296380000 – 2012/2013W.17

The basics of lightning andsurge protectionGeneral installation adviceGeneral installation adviceMany details have to be taken into account during theinstallation of surge protection and the electrical system in orderto achieve optimum protection.Arrangement and subdivision of electrical panelSteel cabinets possess good magnetic shielding properties. Thefollowing points should be taken into consideration during theinstallation:• Avoid unnecessarily long lines(particularly lines with a high volume of data traffic).• Route sensitive signalling lines separately from lines with ahigh interference potential.• Route shielded lines directly to the equipment and connectthe shielding there (do not connect via additional terminal inswitching cabinet).• Classify equipment in groups with different sensitivities andplace these together.Place of installationThe surge protection devices should be mounted where thelines and cables enter the cabinet. This is the lowest mountingrail directly above the cable entries. This prevents interferencebeing coupled within the cabinet; interference is discharged rightat the entry to the cabinet. When using shielded lines, these canbe connected at this point by using Weidmüller clamp straps.Routing the linesSignalling lines should be laid within the system/cabinet over theshortest route to the surge protection and then continue to theconnected equipment. Protected and unprotected lines shouldbe routed separately. The earth line should be regarded as anunprotected line. Metal partitions can be used along cableroutes or in cable ducts to achieve this separation. If signallinglines are laid parallel to power lines, a clearance of min. 500 mmmust be maintained. The best shielding offers metallic cableconduits along with a metal cover.Earthing of products and connected productsAll surge protection devices have an earth-connection terminalpoint. The earthing wire for the associated equipotential bondingrail must be connected to this point. The earthing wire shouldhave as large a cross-section as possible and also be as shortas possible. Every centimetre of extra cable length increasesthe residual voltage of the surge protection device (1 metre /39 inch of cable = 1 kV voltage drop). In addition to the earthingterminal, the surge protection products for measurementcontrol systems also offer the option of earthing via a DINrail contact on a TS 35. In order to achieve the best earthcontact, the rail should be mounted to an earthed metal backwall. In order to obtain a lower protection level, the earthingterminal on the surge protection products (for measurementand control systems) should be connected to the equipotentialbonding every 60 cm / 24 inch. According to IEC 62305, thePE connection and the SPD spur may only be 0.5 m / 20 inchto the lightning protection equipotential bonding. It is possibleto make the path as short as possible by using a so-calledV-connection or by connecting to the accompanying PE.Cable lengthsF1cF2SPDababL 1L 2L 3NPEIt is valid:a + c ≤ 0.5 m / 20 incha + c ≤ 0.5 m / 20 inch,then b is not relevanta + b ≤ 0.5 m / 20 inchSPDb ≤ 0.5 m / 20 inchWbW.181296380000 – 2012/2013

General installation adviceThe basics of lightning andsurge protectionFuse protectionSurge protection devices for instrumentation and controlsystems frequently operate with a decoupling between thecomponents. This decoupling is carried out using inductors orresistors. The decoupling dictates the cable type, cable routingand also a fusing for the maximum nominal current of the surgeprotection devices. The fusing for the PU series on the powersupply side must be installed in accordance with DIN VDE0298 part 4 (cross section, quantity, type of conductor andthe type of installation). This information is documented in thepackage insert and on the products for the corresponding PUmodules. In the event of overloads caused by partial lightningcurrents or transformer short circuits, the lightning arrester andsurge arrester (SPD) must be protected by a back-up fuseif F1 is greater than the value specified by the manufacturer.In compliance with the ratio 1: 1.6, the maximum nominalvalue should be configured for the SPD. Depending on theinstallation of the connecting cables, F1 can be increasedduring the lifespan of the facility. Who is still thinking about surgeprotection? If a circuit breaker or a main circuit breaker is usedinstead of the safety fuse required in the installation instructions,then the triggering characteristics must be followed.Lightning current strength of NH fusesfor surge currents 10/350 µsI limit in kA5010Lightning surge current10/350 µs4.4…6.1 kA2.3…3.7 kA-------Values from the1-ms melting integral110 35 63 100 160 250Fuse nominal currents in A15.6…29.8 kA13.2…16.4 kA6.8…10.3 kALightning current strength of NH fusesfor surge currents 8/20 µs6050Lightning surge current820 µs43…55 kAI max in kA40302018…24 kA28…34 kA12…14 kA-------10Values from the1-ms melting integral2.7…4.3 kA00 10 35 50 63 100 150 160 200Fuse nominal currents in AW1296380000 – 2012/2013W.19

The basics of lightning andsurge protectionGeneral installation adviceBehaviour of NH fuses for lightning surge current(10/350 µs)It is important to understand that the question is not howsmall the SPD fusing should be; rather the maximum back-upfuse should be used. The question becomes clear since thecapacity of the small fuses to carry lightning current is verylimited. Unrestricted SPD protection is only available when theinstallation accommodates the maximum value.Nominal currentand design250A/1200A/1160A/00100A/C0063A/C0035A/C0020A/C0025 kA 75 kA22 kA 70 kA20 kA Melting 50 kA Explosion9.5 kA 25 kA5.5 kA 20 kA4 kA 15 kA1.7 kA 8 kA0 10 20 30 40 50 60 70 I/kA 100S P DWInstallation site of the lightning and surge protection productsW.201296380000 – 2012/2013

Surge protection installation instructionsInstallation instructions for Weidmüller‘s PU I, PU-II andPU-III lightning/surge protection in power gridsThe basics of lightning andsurge protectionThe surge protection should only be installed by trainedpersonnel. Please follow all local regulations concerningconnection methods during the installation.and the power distribution system. All arresters must beinstalled by a qualified electrician. The PU I LCF or PU I TSG+can be installed upstream of the meter. VDE 0100 part 534,4/99 „Selection and installation of equipment“ describes theconstruction of facilities with surge protection equipment.This is related to the following standards:a. IEC 60364-4-43:“Protection for surge voltages from atmospheric origins andfrom switching operations”b. IEC 60364-5-53:“Selection and installation of electrical equipment”c. IEC 61024-1:“Protection of buildings against lightning strikes”d. IEC 61312-1:“Protection against lightning electromagnetic pulses”1 ApplicationThe Class-I PU I lightning protection and the Class-II PU-II surgeprotection are used to protect low-voltage consumerinstallations and electronic devices against surge voltages thatmay arise as a result of atmospheric discharges (thunderstorms)or switching operations.The PU I is a Class-I/II lightning arrester according to IEC61643-1:2009, ENV 61024-1 (1/95) and IEC 1312-1 (2/95). Inthe event of a lightning strike, the required equipotential bonding(lightning protection equipotential bonding according to IEC62305 part 1) between the building lightning protection and theearthing system for the power supply is provided by built-invaristors.The PU II complies with Class II of IEC 61643-1:2009 andÖVE SN60 part 4 and part 1. Metal-oxide varistors are used asvoltage-limiting components. The PU III and PO-DS Class-IIIsurge protection for end devices protect low-voltage consumerinstallations and electronic devices against surges and switchingoperations. The PU III or PO DS is installed in addition to thePU II in the small distributor, floor distributor, cable conduit, ordirectly behind the outlet. They meet the requirements ofIEC 61643-1:2009.2 Installation locationThe PU II needs to be installed in the meter cabinet or in thedistributor so that the space for connection terminals is notaccessible to unauthorised persons. The PU I is installed nearthe power feed so that there is the required lightning currentequipotential bonding between the lightning protection facility3 Electrical connectionThe shortest possible cables should be used to connect the PUI lightning arrester and the PU II surge protector with the phaseconductors (L1, L2, L3) or the neutral wire (N) and the earth (PE)on the consumer installation. Unprotected cables should neverrun in parallel with protected cables (connection examples canbe found on the last page).W1296380000 – 2012/2013W.21

The basics of lightning andsurge protectionSurge protection installation instructionsW3.1 Connection to the phase conductor and the neutralwireFor the connecting cables to the PU I/PU II arresters, normallythe same wire cross-section is used both for the phaseconductors (L1, L2, L3) and the neutral wire (N). If you need toreduce the cross-sections, then a protective device (e.g. a mainport fuse) should be used to protect the connecting cables fromshort circuits. The terminals of the arrester must not be used asbranch terminals. The back-up fuse for the PU II can be be upto 125 A gL. For the PU I, a max. of 160 A gL can be selectedfor the back-up fuse. Serially-connected residual current devices(RCDs) of type S (3 kA, 8/20 µs) must be resistant againstcurrent pulses.Notes:In the TN-CS power grid, 3-pole PU IIs are used (on the TN-Cside). If the PEN conductor uses a separate PE and N, then a4-pole PU II should be used (on the TN-S side). According toDIN VDE 0100-534/A1 10/96, a PU-II- 3+1-280-V protector canbe installed in a TT-type power grid. For an IT grid with a 400-Vphase-wire voltage, the PU II 3+1 385 V should be installed for385 V.3.2 Connection to the earthThe earthing wire of the arrester is connected via the shortestpath to the earthing system of the consumer installation.Longer connecting cables reduce the effectiveness of the surgeprotection. They should not be routed in parallel to other cables.An equipotential bonding rail is available as a connection point inelectrical consumer systems with equipotential bonding. Youmust be certain that the earthing for the arrester is connected tothe earthing system of the consumer installation.In TN power grids, the PEN conductor and the earthing line ofthe arrester should be connected to each other. The PENconductor from the electrical utility may not be used as the earth.If the PE or PEN rail on a distributor is used as the earthingterminal, then the rail must be connected via a separate earthwire to the earthing system of the consumer installation.Two earthing terminals are available on the PU I LCF 30 kA andthe PU I TSG+. Both terminal points must be connected. Oneleads to the equipotential bonding connection on the buildingand the other leads to the PE conductor on the installation.For Class-I lightning arresters, a conductor for carrying lightningcurrent must be used that is at least 16 mm². A minimum crosssectionof 4 mm² is required with Class-II surge protection.4 Installation of surge protection for end devices(Class-III arresters)The PU III or PO-DS arrester is installed together with and afterthe PU II. The PU III or PO DS is built into the cable that is to beprotected. It can then protect a circuit up to 16A. The PU III canbe installed in small distribution boards for one circuit (e.g. forprotecting monitors). The PO DS can be installed in devices or incable conduits on-site.DENIFRECNÜSGVor Isolationsmessung Trennenoder Schutzelement ziehen!Before conducting isolationmeasurement, remove plug-inprotective elements!Prima di misurare l‘isolamentoscollegare il sezionatore o ifusibili di protezione!Avant toute mesure d’isolationdéconnectez les éléments deprotection ou de séparation.Antes de realizar la mediciónde aislamiento, retirar eldescargador.在 做 绝 缘 测 试 前 , 请 先 断 开保 护 回 路 或 拔 下 保 护 模 块 !1267670000/01/20115 Functional checkabSURGE PROTECTIONa + b ≤ 0.50 mIt is important to visually inspect PU lightning arresters andsurge protectors, especially during stormy weather. If the colourof the viewing window changes or if the LED is red, then theSPD must be replaced. As the varistors get older, thetemperature of the varistors may increase. In low-voltagenetworks this can lead to fire. Therefore all SPDs have a built-intemperature monitoring mechanism that isolates the varistorautomatically from the power supply in the event of danger. Asignal or LED indicates that it has been switched off. Anadditional switching contact (remote signalling contact) reportsthis separation (this is labelled with R in all productdesignations).W.221296380000 – 2012/2013

Surge protection installation instructionsThe basics of lightning andsurge protection5.1 ReplacementsWhen an arrester has a red window (as described by point 5) ora red LED, then the arrester should be replaced by a qualifiedelectrician. The individual Class-I/II arresters are pluggable andcoded for voltage.For the insulation resistance test, the SPD must bedisconnected from the facility during the duration of themeasurement (e.g. by pulling out the upper sections) or thearresters are disconnected from the power network. Weidmüllerprovides special notice stickers for the electrical cabinet (ordernumber 1287670000) for this purpose. A proper arrester thatmatches the nominal voltage must be re-installed.6 Connecting the remote signalling (R)The signal contact is designed as a change-over (CO) contact.It is connected to terminals 11 and 14. Terminals 11/12 are innormal operation (window is green) closed and terminals 11/14are open. In the event of an error (red box), the connectingterminals 11/14 are closed and 11/12 are open.For the PU III, the response of the isolating mechanism issignalled when a non-reversible thermal fuse opens.The alert circuit is connected using cables with a maximumcross-section of 1.5 mm². The connecting cables must not berun parallel to the earthing cable. A protective circuit using finesurge protection (Class III) according to the voltage level canreduce interference on and in the evaluation device.7 Back-up fuseThe lightning and surge protection devices in the PU I and PU IIseries behave passively during normal operation. No current isdrawn. This provides the necessary protection against shortcircuits and overloads by using a fuse that is designed for theinstallation method and the cross-section of the connectedcable. The PU product series is also tested with a maximumback-up fuse. This back-up fuse is listed in the technicalspecifications or the side label on the product.If the fuse used in the system has a smaller or equal value (forPU I ≤ 160 A, for PU II ≤ 125 A), then it can be used for cableprotection on the power feed. If the power-feed fuse has a valuegreater than the fuse specified in the technical specifications,additional fuses must be integrated depending on theconnecting cable in the wiring harness of the PU module.Remember that the fuse for the wiring harness is also capable ofcarrying a lightning current. This fuse should not be too smallwhich would make the SPD ineffective during an actual powersurge.8 ApplicationThe PU I LCF, PU I and PU I TSG+ establish the requiredlightning protection equipotential bonding for existing lightningprotection systems and power feeds. The encapsulated PU ILCF, PU I and PU I TSG+ are preferably used in the distributorsin building installations. The blow-out PU I TSG is often installedfor industrial applications (such as wind power facilities) withvoltages of 330 V or 440 V.The PU I LCF and PU I TSG+ products can be used before themeter, since this does not cause leakage current duringoperation. The PU I LCF and the PU I have been certified aslightning protection as well as surge protection. This means thatthey are permitted for Class I and Class II (whereby the PU IIsurge protector is permitted for Class II and III) – surgeprotection and end-device surge protection. PU III and PO DSare Class-III surge protectors for end devices.9 ApprovalsThe PU I and PU-II series have a CB report and can thus berewritten for country-specific approvals.All products bear the CE mark.10 A brief overview of the installation standard forlightning and surge protectionThe foundation is provided by VDE 0100-534 from 02.2009which emerged from the European technical regulations asHD 60364-5-534. This standard specifies the surge protection(Class I or II) that should be installed starting in May 2011.The HD 60364-5-534 need not be identical with the adoptedstandards from each country. The country-specific standardsand application-based standards or rules must be observedduring the installation. The installation must be carried out bylocally licensed professionals.The VDE 0100-534 distinguishes between the connectiondiagrams A, B and C.The following is derived in actual practice:A = 3+0 circuitry (PU I 3 or PU II 3 in the TN-C system)B = 4+0 circuitry (PU I 4 or PU II 4 in the TN-S system)C = 3+1 circuitry (PU I 3 +1 or PU II 3+1 in the PU II TN-S/TT orIT system with N).W1296380000 – 2012/2013W.23

The basics of lightning andsurge protectionSurge protection installation instructionsThe VDE 0100-534 now states that there should be a gap of≤ 0.5 m between the SPD in the vicinity of the installationlocation and the direct connection to N or PE.HD 60364-5-534 specifies that the earth must be establishedfrom the SPD to the equipotential bonding rail or to PE –whichever is the shortest connection. Both cables are specifiedin the VDE.During the insulation test, the SPD must be isolated from thefacility for the duration of the measurement. It is not permitted toconstruct SPDs based on an RCD.Protection against surge currentsL1L2L3PENF1F2PUThe F2 fuse ensures protection against SPD short circuits.These fuses should be chosen based on the rated currentslisted in the installation instructions from the SPD manufacturer.The F2 fuse does not need to be used when the characteristicsof the F1 fuse (which is part of the electrical facility) correspondto a combination of the rated currents specified by the SPDmanufacturer.WW.241296380000 – 2012/2013

Standard texts for surge protection tendersStandard texts for tendersThe basics of lightning andsurge protectionYou will find standard, up-to-date texts for tender documentsat our Internet site www.weidmueller.com – select language:German. These will help you draw up the specification to suityour installation.The advantage of this is that you can download the correct,up-to-date technical information from our Internet site at anytimePlease visit our online catalogue on our homepagefor more product information.www.weidmueller.comW1296380000 – 2012/2013W.25

The basics of lightning andsurge protectionOffice building with lightning protectionApplications, installation positions:Application Office buildingLPZ OALPZ OB3LPZ OA6 83 9436 8 7 8EMABMARV9436 8 7 8HAK12PAS3 95 68Power (low-voltage supply)1 Class I Arresters with sparkover gaps with/without high-power varistors, PU I LCF, PU 1 TSG+2 Class I Arresters with high-power varistors, PU I series3 Class II Arresters with high-power varistors, PU II series4 Class III Arresters for installing in subdistribution boards, PU III series5 Class III Arresters in the form of plug-in surge protectors, PO DSData8 Surge protection for data lines, e.g. Ethernet CAT.5WPower and data6 Class III Arrester VSPC7 Class III Arrester VSPCInstrumentation and control equipment9 Surge protection for measurement and control circuits, e.g. MCZ OVP series, VSPC or VSSCW.261296380000 – 2012/2013

Applications, installation positions:Application Industrial buildingIndustrial building with lightning protectionThe basics of lightning andsurge protectionLPZ OALPZ OB336 8 7 89346 87 8EMA9444BMARV36 8HAK12PAS3 95 68StandardsIEC 61643-1 Ed.2 2005-03, SPDs connected to low-voltage power distribution systems.Class I, Class II and Class III products are tested in accordance with this standard.IEC/EN 62305-1 until 4,- Protection against lightning.This lightning protection standard defines everything to do with internal and external lightning protection.It includes four sections:• “Protection against Lightning – Part 1: General principles”• “Protection against Lightning – Part 2: Risk management: assessing the damage risk for buildings and structures”• “Protection against Lightning – Part 3: Physical damage to structures and life hazared”• “Protection against Lightning – Part 4: Electrical and electronic systems within structures”Regulations for installationIEC 60364-5-53: 2002-6, Electrical installations of buildings – Part 5-53.Standard for the installation of low-voltage facilities.VDE 0800, VDE 0843-T5, and VDE 0845 describe the selection and installation for communication electronics.Guidelines for the SEV lightning protection system SN 4022:2004 and the SEV 4113 foundation earthCurrentTelecomGasWaterLPZ OAUnprotected area outside of thebuilding. Direct lightning strike; noshielding against electro- magneticinterference.LPZ OBArea protected by lightningprotection system. No shieldingagainst LEMP.W1296380000 – 2012/2013W.27

The basics of lightning andsurge protectionComponents for Surge protectionComponents for Surge protectionWSurge protection devices(SPD = surge protection devices)here is no ideal component that can fulfil all the technicalrequirements of surge protection equally effectively. Instead, weuse a variety of components whose different physical methodsof operation complement each other; these possess distinctprotective effects. Super-fast reaction time,high current-carrying capacity, low residual voltage and longservice life cannot be found in one single component.In practice we use three principal components:1. spark gaps2. varistors3. suppression diodesTherefore, to optimise the surge protection, carefully matchedgroups of these components are often combined in oneprotective module.4. Combination circuits1. Spark gapsU(kV)1.00.51µs tU(kV)1.00.5Possible types:Blow-out spark gapEncapsulated spark gapGas-filled spark gapPulse form shape without GDT Pulse form shape with GDT1µs tThe name says it all. High voltages are discharged to earth viaa spark gap (e.g. gas discharge tube) that has been fired. Thedischarge capacity of sparkover gaps is very high – up to 100 kAdepending on type.Gas sparkover gaps are incorporated in insulating glass or ceramic(aluminium oxide) housings. The electrodes of the sparkovergap are made from a special alloy and placed in housings whichare vacuum seald and filled with a noble gas such as argon orneon. They are aligned with respect to shape and clearancedistance, so that the applied voltage produces a distribution offield strengths. This results in a fairly precise voltage value for thecomplete ignition of the spark gap. The housings are vacuumtightand filled with an inert gas such as argon or neon. The sparkgap has a bipolar function. The ignition voltage value, however, isdependent on the steepness of the applied surge voltage.The ignition characteristic curve for gas-filled spark gaps revealsthat the ignition voltages increase for those surge voltages whichclimb more steeply. The consequence is that, for very steepsurge voltages, the ignition voltage (that is, the protection level) isrelatively high and can be well in excess of the rated voltage forthe spark gap (approx. 600–800 V). The problematic quenchingbehaviour of the fired sparkover gap can be a disadvantage. Thearc has a very low voltage and is only extinguished when thevalue drops below this. Therefore, when designing the geometryof a sparkover gap, care is taken to ensure that – through longdistances and also through cooling – the voltage of the arcremains as high as possible and so is quenched relatively quickly.Nevertheless, a longer follow current can ensue. This can draw itsenergy, in addition, from the incoming supply of the circuit to beprotected. One effective solution is to wire a sparkover gap and afast-acting fusible link in series.W.281296380000 – 2012/2013

Components for Surge protectionThe basics of lightning andsurge protection2. Varistors / MOV3. Suppression diodes / TAZUUUUttttThe varistors used with surge protection (MOV-Metal OxideVaristors) have resistance which depends on the voltage. This isimplemented with metal-oxide (zinc-oxide) discs. There is a lowohmresistance in the range above the rated voltage. The surgevoltage is limited since a current flows through the varistor. Thevaristor works bi-directionally.Depending on the type, varistors have either a middle or highdischarging capacity. It is in the range from 40 kA to 80 kA.The response time is less than 25 ns. However there are alsodisadvantages when using varistors. Two factors that must betaken into account are the relatively high capacitance and theaging characteristics.Leakage currents occur over time, depending on the frequency ofthe triggering, because individual resistance elements break down.This can cause temperature rise or even destroy them completely.This is one reason for thermal fuses being built into Weidmüllerproducts. The high capacity of the varistors is problematic forcircuits with high frequencies. Some signal attenuation should beexpected at frequencies above 100 kHz. We therefore recommendthat they are not used in data transmission systems.Suppressor diodes function in a similar fashion as Zenerdiodes.There are uni-directional and bi-directional versions. Unidirectionalsuppressor diodes are often used in DC circuits.Compared to standard Zener diodes, suppressor diodes have ahigher current-carrying capacity and are significantly quicker. Ata certain breakdown voltage level, they become conductive veryquickly. They therefore discharge the surge voltage. Howevertheir current-carrying capacity is not very high. It is only a fewhundred amps. Instead, they feature a very quick reaction timewhich lies in the picosecond range.Unfortunately, suppression diodes possess a significant inherentcapacitance. Therefore, like with varistors, their possibleattenuation effect on high frequencies must be taken intoaccount.W1296380000 – 2012/2013W.29

The basics of lightning andsurge protectionComponents for Surge protection4. Combination circuitsCombining the components described above results in surgefine protection products that can match individual requirements.If a voltage pulse reaches the input of such a combinationcircuit, then the gas discharge tube is fired and dischargeshigh current. The residual pulse is attenuated by a downstreaminductance and subsequently received and limited by thevaristor and/or suppression diode. If the gas discharge tube isnot triggered, i.e. in the case of a slower voltage rise, then thepulse is discharged by the varistor or the suppression diodealone.The sequence of the individual components results in anincreasing response sensitivity towards the output. Aninterference voltage with a rise of 1 kV/µs and a peak valueof 10 kV at the input is limited by a gas-filled surge arrester toapprox. 600-700 V. The second stage, decoupled from the firstby means of an inductance, suppresses this value to approx.100 V. This voltage pulse is then reduced to approx. 35 V(in a 24 V protective combination) by the suppression diode.Therefore, the downstream electronics need only be able tocope with a voltage pulse of approx. 1.5 x U BkVVVV1060060060085005005006400400400300300300420020020021001001000Surge voltage wave0000 20 40 60 µS0 1 2 µs0 1 2 µs0 1 2 µsWU BUW.301296380000 – 2012/2013

Test criteriaTest criteriaThe basics of lightning andsurge protectionThe classification is based on the experience that “B arresters”can become overloaded in extreme situations, and also on morerecent investigations into lightning discharges. This resulted inthe standardised 10/350 µs current curves for the testing of“class I” arresters. The test parameters lie between12,5 and 25 kA I peak or I imp .The term “10/350 µs” means that the surge current reaches90 % of its maximum value after 10 µs and then decays tohalf that value after 350 µs. The area beneath this curvecorresponds to the current energy used in the test. As in thepast, “class II” arresters (formerly “C arresters”) are tested withthe 8/20 µs current curve. The rated discharge current for ourarresters: for a 2-pole feed up to 75 kA; for a 4-pole feed up to100 kA. “Class III” arresters (formerly “D arresters”) are used forprotecting equipment. These are tested with a 2 W hybrid surgeClassification Test values Applicationformerly VDE IEC067537AcoarseprotectionB-arresterclass I I IMP = 25 kA10/350 µs curveProtection against directlightning strike (incoming(supply, main distributionboard, etc.)medium C- class II single poleProtection for permanentprotection arresterI N = 20 kAinstallations (electricity8/20 µs curvedistribution etc.)3 or 4-poleI N = 100 kA8/20 µs curvefineprotectionD-arresterclass III U oc = 20 kV max.I s = 10 kA max.hybrid generatorProtection for devices(sockets etc.)current generator delivering a maximum charging voltage of0.1 to max. 20 kV, which during a short-circuit supplies between0.05 and 10 kA, 8/20 µs.Relationship between 10/350 µs and 8/20 µs100 kA80 kA60 kA50 kA40 kA1Wave form[µs]I max [kA]Q [As]1 210/350 80/20100 550 0,120 kA220 200 350 600 800 1000tUSW/R [J/Ω]Norm2.5 – 10 6 0.4 – 10 3DIN V VDE V0185-1DIN V VDE0432 T.2Simulated surge pulse 8/20 µsSimulated lightning impulse 10/350 µsTest pulse 10 / 350 µs10090Voltage in %501000 50 100 150 200 250 300 35010350t in µsTest pulse 8 / 20 µsTest pulse 1.2 / 50 µs1009010090Voltage in %5010005 15 25820t in µsVoltage in %50100010 20 30 40 501.2t in µs50W1296380000 – 2012/2013W.31

The basics of lightning andsurge protectionElectromagnetic compatibilityElectromagnetic compatibilityEMC – electromagnetic compatibility – means the troublefreeinteraction between electrical and electronic systemsand devices without mutual interference. In this respect,any electrical item can act both as transmitter (source ofinterference) and receiver (potentially susceptible device)simultaneously.Normally it is not sufficient to construct an EMC-compliantelectrical or electronic system using EMC-compliantcomponents and to then expect that everything will operatesmoothly. Only when you use the proper surge protectiondevices in the proper places in the facility, can you operatewithout outages using coupled surge voltages. The method forusing surge protection devices is also linked to the influence ofinterference sinks and interference sources. It integrates with thelightning protection zone strategy and insulation coordination toform a complete protection system.Electrical system 101234MSR501234MSR5Electrical system 2EMC laws and directivesThere are a multitude of standards and statutory requirementsaimed at controlling mutual interference-free operation. With theestablishment of the unified European market in 1989, the EECDirective (EN 50-370 part 1+2) on electromagnetic compatibilitywas adopted and then implemented into national law. InGermany, the law on the electromagnetic compatibility (EMVG)was endorsed in 1992. The current version of this law waspassed in 2008 as was the international standard IEC 61000.Electromagnetic influences can be caused by natural processes,e.g. a lightning strike, and also technical processes, e.g. highspeedchanges in the status of currents and voltages.We distinguish between periodic interference (system hum,RF irradiation), transient interference (brief, often high-energypulses) and noise (broad distribution of interference energyacross the frequency range).The model used in EMC observations designates the transmitteras the source of interference emission and the receiver as theinterference drain. The transmission of the interference takesplace via line-bound and/or field-bound (H-field/E-field) couplingmechanisms.When considered as a source of interference, a device or asystem may not exceed emissions thresholds specified in theEMC standards.When considered as a potentially susceptible device, the samesystem must exhibit the immunity to interference specified in thestandards.However, the arrangement of various electrical systems withina complex plant or in a room and the many lines for powersupplies, inputs and outputs to controls and bus systems giverise to diverse potential influences. Surges can be introducedby lightning, switching operations, etc. via the various couplingpaths. This can lead to the following effects:• reduced functionality• malfunctions• failure of functions• damageWW.321296380000 – 2012/2013

Electromagnetic compatibilityThe basics of lightning andsurge protectionThese last two functional interferences result in stoppages forentire production facilities and cause high breakdown costs.The following points must be taken into account in order toachieve a system or plant that operates according to EMCguidelines:• lightning protection• earthing• routing of cables• cable shielding• panel construction• sensors and actuators• transmitters and receivers• frequency converters• bus and field devices• ESDConductive couplingElectrical system 101234MSR5Inductive couplingCapacitive coupling01234MSR5Electrical system 2Radiation couplingSourcePotentiallyW1296380000 – 2012/2013W.33

The basics of lightning andsurge protectionQuestions and answers concerning surge protectionFAQ listWWhen do I need a class I arrester,when a class II arrester?In a lightning protection system set up ona building, the class I arrester achievesthe lightning protection equipotentialbonding for the supply voltage. The classI arrester is used when higher pulses areexpected and is installed in the vicinity ofthe incoming supply.The Class-I arrester is intended for use inlightning protection equipotentialbonding, in compliance with DIN VDE0185 part 1 and IEC 62305. The Class-Iarrester meets the requirements ofClass I (B) DIN VDE 0675 andIEC 61643-1 Class I.The Class-II arrester is used to protectlow-voltage consumer installations andelectronic equipment against surgevoltages arising from atmosphericdischarges (thunderstorms) or switchingoperations. The Class-II arresters complywith VDE 0675 part 6, Class II (C), Draftand DIN VDE 0675 part 6, A2 and theIEC 61643-1-1 Class II.When is a decoupling inductanceneeded?When using Weidmüller arresters of classI and II based on varistors, no decouplinginductance is needed. The PU1 TSG +operates with a triggered sparkover gap.The fast response and low protectionlevel mean that no decoupling is requiredhere either.Why are there 3- and 4-poleversions?Various arresters are used depending onthe network structure. A widely usednetwork structure is the TN system. Inthe TN-C system, the electricity supplycompany routes the potential of theoperational earth of the low-voltagesource (transformer) to the consumerinstallation via the integral PENconductor. The PE conductor has thesame potential as the N conductor in thiscase. A 3-pole arrester is used here.Every rule has an exception: in the TN-Ssystem, PE and N are separate. Thismeans there can be a potential shiftbetween PE and N. A 4-pole PU is usedin this case. In addition, a combination of3 or 4-pole modules reduces the amountof wiring.What other network structures areavailable?TT-SystemIn the TT system, surge protectionClass-I/II arresters are not used betweenthe active conductor and the earthpotential like in TN systems. Instead theyare used between phases L1, L2 and L3and the neutral conductor.In a „classic“ arrangement of surgeprotection devices between the phasesand the earth potential, the devices maynot be capable of extinguishing mainsfollow currents at the end of theirlifespan. They could even create a shortcircuit. Depending on the earthresistance that exists for the consumerinstallation, a fault current could flowback to the supply source. Usually,because of the relatively high loopresistances in TT systems, the fuseswhich conduct the operating current donot detect this fault current as a fault andthus do not isolate promptly. This canlead to increases in potential in thebuilding‘s entire equipotential bondingsystem. Dangerous parasitic voltages canbe transferred if more distant building arebeing supplied from these consumersystems or if consumer loads are beingoperated via portable cables beyond therange of the building‘s equipotentialbonding system. The 3+1 circuitry can beused in such instances.IT-SystemAn IT system is set up in some consumerinstallations for reasons of availability. Asingle-phase earth fault practically createsa TN system. The power supply is notinterrupted but instead maintained. ITsystems are used in medical applications,for example. A device formonitoring insulation provides informationon the quality of the insulation of activeconductors and connected consumers inrelation to the earth potential. Surgeprotection devices are incorporatedbetween the active conductors and themain equipotential bonding. The fuses,conductor cross-section and conductorroutes are handled as for T systems.Likewise, all active conductors areprotected against local earth potential insub-circuit distribution boards. PU surgeprotection devices in Class III surgeprotection for end devices are used (suchas PU III or PO DS) to protect sensitiveconsumer loads. The arrester must besized for the voltage of the phaseconductor.W.341296380000 – 2012/2013

Questions and answers concerning surge protectionThe basics of lightning andsurge protectionWhat does this have to do with the3+1 circuitry?If Class-II arresters are now being led toa neutral conductor instead of a localearth in a TT system, then, for an arresterthat has become low ohm, only the wireresistance of the neutral wire limits theincipient follow-on current. Immediatelyafter the fault, this is isolated from thespur line fuses or from the main fusesthat are carrying the operating current.A pure short-circuit current has emergedout of a fault current that was subject toan earthing facility and resistor. Theconnection between the neutralconductor and the main equipotentialbonding is established using a spark gap.This conducts the total surge currentsoccurring at the installation site withoutoverloading. This 3+1 circuitry is alsoimplemented for the circuit distributors.The phase conductors L1, L2 and L3 areconnected via the neutral conductor.From there, a spark gap link isestablished with the PE rail. The sameinformation on the TN system applieswhen working with local equipotentialbonding systems, when there is aseparate discharge to the equipotentialbonding, and when the surge protectioncomponents are being arranged ahead ofthe fault-current protective circuits.How does monitoring work with PUarresters?Each individual element of the PUarrester is equipped with a thermalmonitoring mechanism. This state-of-theartdesign isolates the aged arrester fromthe power supply network. This helps toprevent fires. This thermal monitoringmechanism functions using a specialsolder which separates itself within 30seconds when a current of about 0.2 Aflows through the varistor.The functionality is indicated when theviewing window is green, or for the PUseries with arresters marked R, using aremote alert output with a CO contact.Does a lightning/surge protectionsystem continue to operate after asurge voltage?Yes, when the leakage current (e.g. forthe PU II) remains under 40,000 A foreach individual element. However thevaristor does age during each discharge.The ageing accumulates over time andthen leads to the failure of the arresterafter several years. This can bemonitored by a remote signallingmechanism or in accordance with anearly warning EWS. Another method,which is required by IEC 62305-3, is aperiodic check of the lightning protectionsystem. The V-TEST can help by allowingyou to test the function of each individualmodule.How are the PU modules tested?The PU I and PU II are tested inaccordance with IEC 61643-1:2009. Thearresters from the PU I series correspondwith Class I and Class II. The PU II seriescorresponds with Class II and Class III.The PU III and PO DS series aredesigned and tested in accordance withthe requirements of IEC 61643-1.They are in Class III.Where are the PU modules installed?The dimensions of the PU modules forinstallation distributors, comply with DIN43 880 A1 draft 6/81. The Class-Iarresters are installed in the vicinity of thepower feed and main equipotentialbonding. The Class-II arresters areinstalled in the distributor and the PU IIIare installed in the sub-distributions,closer to the object being protected. Theinsulation coordination in DIN VDE 0110requires that facility components havecertain insulation strengths. This can beachieved through the gradual applicationof arresters in Class I, II and III.What must be considered wheninstalling the PU modules?IEC 60364-5-53 describes the selectionand installation of surge protection inbuildings worldwide. The German draftstandard DIN V VDE V 0100-534describes the selection and set-up ofsurge protection systems.What is the difference between aspark gap and a varistor?A varistor is a voltage-dependent resistorwhich switches off the surge voltage„softly“. A spark gap is a mechanicalcomponent or an encapsulated, gas-filledceramic unit whereby the spark gapswitches through immediately, and afterthe spark, only the ignition voltage ispresent (80 – 120 V). Depending on thetype of spark gap, the capability tosuppress the 50-Hz mains follow-oncurrent must also be considered. Thevaristors, however, do not draw anymains follow-on current.What are triggered spark gaps?These spark gaps have additionalelectronics. They “see” the interferencepulse and ignite the spark gap. Thismeans that the protection level is keptlow and the time to spark is reduced.This saves on decoupling coils.W1296380000 – 2012/2013W.35

The basics of lightning andsurge protectionQuestions and answers concerning surge protectionWhen should I use CL or SL circuitswith surge protection componentsfor measurement and controlsystems?The difference between the switching inthe CL (current loop) and SL (symmetricalloop) is the integration of the suppressordiodes. The CL circuit has a diodebetween the lines. This system is used forcurrent loops and offers direct protectionat the input or output of the analoguesensor.The SL circuit operates symmetrically toearth, i.e. two Transzorb diodes areconnected to earth. If this is used in acurrent loop instead of the CL circuit, theresidual voltage is twice as high becausethere are two diodes instead of just theone of the CL circuit.2 CL protective circuit1 45TS2 32 SL protective circuit1 45TS2 3WW.361296380000 – 2012/2013

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The basics of lightning andsurge protectionGlossaryGlossaryW3 +1 circuit Surge protection for TT-/TNS power networks with 3 varistors and an N-PE sparkgap. There are no parasitic voltages in the event of defective varistors.AgeingChange in the original power data caused by interference pulse due to operations orunfavourable environmental conditionsArrestorProtective device that the discharges the energy either symmetrically between theconductors or asymmetrically between the cables and the earth.Asymmetric interference voltage Voltage between the “electrical centre”, and common ground (earth)Voltage between conductor and signal ground (earth)Back-up fuseDependent on the connection cross-section and/or maximum longitudinal decouplingof the proposed fuseBinary signalsSwitching signals with on and off statesBurstFor a surge pulse that reoccurs during a specific time intervalCable lengthsWith a spur line connecting the lightning arrester, the length of the phase-side andearth-side cables should be kept as short as possible and should never be longerthan 0.5 metres / 20 inch. The earth-side connection should especially be as shortas possible. Installation site: At the feed point of the facility, for Class I and II. In theimmediate vicinity of the end device being protected for Class III.Capacitive couplingCoupling of the interference circuit and the useful circuit because of a potentialdifference with coupling capacitancesClass IFor the purpose of lightning protection equipotential bonding according toIEC 37A/44/CDV; also refer to requirement class BClass IIFor the purpose of surge protection in the fixed facility, preferably for use in impulsewithstand voltage category III, also see requirements class BClass IIIFor the purpose of surge protection in the fixed facility, preferably for use in impulsewithstand voltage category II, also see requirements class BCombination circuitProtective circuit (e.g. from gas discharge tube, varistor and/or suppressor diode)Combined pulseThe hybrid generator, when idle, creates a 1.2/50 µs pulse and, when in short circuit,a 8/20 μs pulse. The ratio of peak open-circuit voltage (U0c) to peak short-circuitcurrent (Isc) is 2 ohms.Common-mode interferenceThe interference source is between a signal wire and a reference conductor (e.g.capacitive coupling, or increase in potential of spatially dispersed earths).Continuous operating current I c Current per protective path for continuous voltage UcCut-off mechanismDevice which disconnects the arrester in case of a system malfunction and displaysthisDegree of protection for housing(IP code)Differential-mode interferenceEMCDegree of protection ensured by the housing against touch access to live parts andagainst the ingress of solid foreign objects or water. Testing in accordance withIEC 529 section 7.4.Interference source and useful source are in series (e.g. magnetic or galvaniccoupling).Electromagnetic compatibilityW.381296380000 – 2012/2013

GlossaryThe basics of lightning andsurge protectionExternal lightning protectionFollow-on current I fFuse, back-up fuseGalvanic couplingGas discharge tubeHAKI&CIMAXInductive couplingInsertion loss (attenuation)INSTAInsulation coordination or ratedimpulse withstand voltageInternal lightning protectionIntrinsically safe circuitIpeak = I impI snIT power networkLeakage currentLEMPLightning protection equipotentialbondingLightning pulse current I impLimiting frequencyThe external lightning protection consists primarily of an air-termination device,arresters and an earthing system. It is responsible for protecting the facility buildingsfrom lightning strikes which could cause fire or mechanical destruction.Current that flows through the surge protection device immediately following adischarge and is delivered from the power gridA back-up fuse is required if the upstream fuse F1 is greater than the maximumvalue specified by the manufacturer. Remember to select the largest nominal valuein keeping with the ratio F1 to F2 (back-up fuse before SPD) = 1 : 1.6. Be sure totake the triggering characteristics into account if a circuit breaker is being usedin the surge protection equipment instead of the fuse specified in the installationinstructions.The interference circuit and the useful circuit have a common impedance.Voltage-dependent, encapsulated switch with high current-carrying capacityHouse junction boxMeasurement and control systemsMaximum current that can be switched by an arresterCoupling from two or more current-carrying conductor loopsAttenuation in decibels that is added by inserting a four-poleInstallation housing in accordance with DIN 43880, suitable for installation indistribution boardsStanding surge current strength of the insulation in parts of the facility, according toDIN VDE 0110 T.1Internal lightning protection refers to protecting electrical equipment from powersurges.Intrinsically safe circuits are especially vulnerable because even a small amount ofenergy is sufficient to nullify their intrinsic safety. During the installation of intrinsicallysafe circuits (including cables and wires), be sure that you do not exceed themaximum allowable inductance, capacitance, or the L/R ratio and the surfacetemperature.Current peak value of a test pulsePeak value of the nominal discharge currentPower system with three phase conductors, constructed with insulation to the earthpotential. The building's PE is not connected to the power gridCurrent that flows to PE at nominal voltageLightning electromagnetic pulse = electromagnetic interference pulseEquipotential bonding of separated metal parts with the LPS using a directconnection or connection via surge protection devices in order to reduce thelightning current caused by the potential differenceDefined by the peak value Ipeak and the charge Q, when tested in accordance withClass I with 10/350 µs pulseSpecifies the max. frequency at which a transfer will function. At higher frequencies,the protective circuit cushions so strongly that no transfer is possible.W1296380000 – 2012/2013W.39

The basics of lightning andsurge protectionGlossaryWLongitudinal voltageInterference voltage between the active conductor and the earthLPLLightning protection levelLPL I = 200 kA LPL II = 150 kA LPL III = 100 kAMaximum lightning current that can enter as a direct strike in the external lightningprotection. Various applications and buildings are categorised according to theselightning protection levels.10/350 µs: test current for lightning arrester (type or Class I products), for simulatingor reproducing a lightning bolt.8/20 µs: test current for lightning arrester (type or Class II products), for simulating orreproducing a surge voltage.LPSLightning protection system – a complete system that is used to reduce the physicaldamage to a building or facility that could be caused by direct lightning strikesLPZLightning protection zone = lightning protection zone The lightning protection zonesare divided into: external lightning protection LPZ 0 / 0A / 0B and internal lightningprotection LPZ 1, 2, 3Max. continuous voltage UcThe highest RMS value of the AC voltage or the highest value of the DC voltage thatis allowed continually on the protective path of the surge protection device. Continualvoltage = rated voltage.Maximum discharge surge current I max Peak value of the current 8/20 µs during duty test for Class II (type 40 kA)Measured limiting voltageMax. voltage level while loading with pulses of a specific form and amplitude duringthe testMOVSee varistor.Nominal discharge surge current At peak value of the surge current 8/20 µs, during test for Class II (type 20 kA)PAS main earth railMetal rail which is connected with the foundation, and which can be used toconnect metal installations, external conductive parts, power supply cables,telecommunications cables, water pipes and gas pipes to the LPSPEProtective system and earth system to which energy is dischargedProtection level, U pSpecifies the residual voltage that can still be measured at the terminals during asurge voltage pulse (preferred value is greater than the largest measured limitingvoltage). Important parameter that characterises the performance of the SPD.Protective pathComponent circuity in a SPD: conductor to conductor, conductor to earth,conductor to neutral, neutral to earth are designated as protective paths.Pulse current 10/350 µs Pulse voltage with a front time of 10 µs and a half-value time of 350 µsPulse current 8/20 µs Pulse voltage with a front time of 8 µs and a half-value time of 20 µsPulse voltage 1.2/50 µs Pulse voltage with a front time of 1.2 µs and a half-value time of 50 µsRadiation couplingElectromagnetic field coupled to one or more conductive loops.Rated voltage UCThe maximum RMS value of the AC voltage which may continuously be applied toan arresterRCD circuit breakerIf a fault current exceeds a certain threshold, then the RCD switches off within0.2 seconds.Recommended fuseThe nominal value of the fuse recommended by the manufacturer and specified bythe technical data sheet.W.401296380000 – 2012/2013

GlossaryThe basics of lightning andsurge protectionRemote alert contact (FM)Requirement class B / T 1 / Cl.IRequirement class C / T 2 / Cl.IIRequirement class D / T 3 / Cl.IIIRSUShort-circuit withstand ratingSparkover timeSPDSuppressor diodeSurge protection (OVP/SPD)Surge protection device (SPD)Surge protection equipment (SPE)Surge voltageSurge voltage protection classesSymmetric interference voltageTAZTN power gridTransverse voltageTriggered sparkover gapTT power gridVaristorA volt free contact for the power products for signalling triggered/defective arresters.For the measurement/control-SPD-/VSPC products, this connection with the VSPCCONTROL UNIT is required to produce a signal. The Weidmüller diagrams show thiswith the letter R which stands for "remote signal contact".For the purpose of lightning protection equipotential bonding according to DIN VDE0185-1, also see Class IFor the purpose of surge protection in the fixed facility, preferably for use in impulsewithstand voltage category III, also see Class IIFor the purpose of surge protection in the fixed facility, preferably for use in impulsewithstand voltage category II, also see Class IIISurge protection on clip-on base with gas discharge tube, varistor and suppressordiode for 6-A and 10-A current loopsMaximum prospective short-circuit current that the surge protection device canwithstandResponse times can vary between a few µs to ps, depending on the type andconstruction of the protective components.Surge protection device (lightning and surge protection device)Voltage-dependent, fast-switching semiconductor diodeSwitching circuitry/wiring of a circuit used to limit the output voltage; and the sumof all lightning protection measures used to protect the technical equipment againstlightning currents and surge voltagesDevice with at least one non-linear component, used to limit the surge voltages andto discharge the surge currentsSurge protection devices and surge protection equipment for a facility, including thecables associated with the surge protectionUnwanted continuous or short-term differences in potential between the conductorsor between conductor and earth which create interference or destructionClassification of electrical equipment in accordance with their dielectric strengthrelative to the nominal voltage, EN 50178Voltage between the outward and return conductors (differential-mode voltage)See suppressor diode.Power grid as a 4 - or 5-wire system; 3 phases and the PEN come into the building.PE from the building and PE from power system are connected to each other.Interference voltage between two conductors in circuitA gas-filled sparkover gap which is ignited by a capacitive voltage divider with apre-set voltage valuePower system with 4 wires; 3 phase conductors and the neutral conductor comeinto the building. The building's PE is not connected to the power gridVoltage-dependent metal oxide resistor; the resistance decreases with increasingvoltage.W1296380000 – 2012/2013W.41

The basics of lightning andsurge protectionCountry-specific standards and directivesSurge protection forumConstruction standards/directives/legal basisThe availability of electrical and electronicequipment and systems is a decisivefactor for the operator, at times for theircontinued existence. It is thereforeimportant to prevent loss and faults thatare frequently caused by overvoltageevents.For this reason, the standards anddirectives relevant to this demandlightning and surge protection forbuildings, parts of buildings, structuraland technical installations (objects).The technical committee IEC TC 81 dealswith lightning protection issuesworldwide. The new IEC 62305 serieswas introduced following a decision inOctober 2001. Since January 2006 thereare four parts of the IEC 62305 series:• IEC 62305-1: General principles• IEC 62305-2: Risk management• IEC 62305-3: Physical damage tostructures and lifehazard• IEC 62305-4: Electrical and electronicsystems within structuresThe German committee responsible forGerman implementation decided tomaintain the VDE classification of thenew standard series DIN EN 62305 asVDE 0185-305 parts 1-4.Country-specific standards anddirectives• DIN EN 62305-1(VDE 0185-305-1):2006-11• DIN EN 62305-2(VDE 0185-305-2):2006-11• DIN EN 62305-3(VDE 0185-305-3):2006-11• DIN EN 62305-4(VDE 0185-305-4):2006-11Part 5 of the draft standard is nowpending in the advisory stage.It is known that lighting protectionequipotential bonding is not sufficient initself to protect electrical equipment fromvoltage surges.On account of that, standards such as:• DIN VDE 0100 part 410• DIN VDE 0100 part 540• DIN VDE 0100 part 443• DIN V VDE V 0100 part 534• DIN VDE 0800 part 1• DIN VDE 0800 part 2• DIN VDE 0800 part 10• DIN VDE 0845 part 1• DIN VDE 0845 part 2explicitly require measures for protectionagainst voltage surges.In DIN VDE 0100, the surge protectionmeasures for low-voltage installations and,in the DIN VDE 0800 series, thesurge protection measures forcommunication engineering as a whole aredescribed. Appendix A of DIN V VDE V0100-534 shows the selectively gradeduse of surge arresters of class I(B arresters) in the main power supply,class II (C arresters) in the sub-circuitdistribution board and class III (D arresters)in the area of the final circuit.Appendix A of DIN V VDE V 0100part 534.IEC 61643-5-53 has been available since2002. It is implemented in the VDE 0100-534 and describes the selection andinstallation of surge protection for electricalfacilities. This is intended as a replacementfor DIN VDE 0100-534. The internationalequivalent is the IEC 60364-5-53:2002-06.The chapter 534: “Devices for protectionagainst overvoltages” contains thedevices for protection againstovervoltages, the selecting of these andtheir use in the building installation. Therules that apply on the low voltage sideare adapted to communicationelectronics as a whole and are describedby the national series of standards 0800parts 1, 2 and 10 and 0845 parts 1 and2. DIN VDE 0800 describes generalissues such as earthing, equipotentialbonding, etc. and DIN VDE 0845the measures for protecting againstovervoltage events of all kinds.Guidelines of the loss insurersWThe guidelines apply to decisions onwhether lightning and surge protectionis to be provided for buildings, parts ofbuildings, structural and technicalinstallations. The guidelines become,on agreement, a binding part of theinsurance contract between insurer andpolicyholder.W.421296380000 – 2012/2013

Country-specific standards and directivesThe basics of lightning andsurge protectionHowever, their application does notexempt the insured party fromobservance of legislation, statutoryinstruments, official requirements andgenerally accepted codes of practicesuch as that described in the DIN VDEstandards.The building regulations ofdifferent countries and the relevantstatutory and official regulations andcodes of practice, call for lightningprotection systems to be installed incertain buildings for reasons of publicsafety, e.g. in shops, hospitals, schoolsand children‘s homes, etc.The generallyacknowledged code of practice, in thiscase DIN EN 62305 (VDE 0185-305):2006-11 or transitionally also DIN VVDE V 0185:2002-11, must be adheredto when installing technical systems.Issues relating to the installation arise notonly in connection with officialrequirements but also when the insurerscall for lightning protection, e.g. for highrackingwarehouses or plants with a highrisk of explosion. Similar relationshipsapply to surge protection. For example,DIN VDE 0100 part 443 specifies riskfactors which determine the installation ofsurge protection measures.The Association of German PropertyInsurers (VdS) publishes a number ofdocuments covering particularapplications, e.g. electrical installations,IT systems, agricultural businesses andresidential buildings:• VdS 2192: Leaflet on surge protectionfor loss prevention• VdS 2014: Determining causes ofdamage due to lightning and surge• VdS 2258: Protection against surge• VdS 2006: Lightning protection bymeans of lightning arresters• VdS 2017: Lightning and surgeprotection for agricultural businesses• VdS 2031: Lightning and surgeprotection in electrical installations• VdS 2028: Foundation earth electrodesfor equipotential bonding and lightningprotection earth termination• VdS 2019: surge protection inresidential buildings• VdS 2569: surge protection forelectronic IT systems• VdS 2010: Risk-based lightning andsurge protection• VdS 2007: IT installations• VdS 3428: surge protection devicesFurthermore, in Germany lightningprotection is also covered in theconstruction law requirements of theindividual federal states and also innational regulations. In light of thissituation, the Association of GermanProperty Insurers has produced a table tosimplify the assignment of lightningprotection classes and surge protectionrequirements to buildings andinstallations (VdS guideline 2010, 2005-07). This takes into account theexperience and findings of lossprevention experts as well as legislation,official regulations and standards.Legal basisBasically, lightning and surge protection isnot a mandatory provision in the form oflegislation, even though lightning andsurge protection is covered in Germany‘sEMC Act.However, it is important to know thatthere is indeed a legal basis. This comesinto play when a loss event has occurredand, as a result, legal proceedingsbecome relevant.In Germany, the following legal aspectsmust be taken into account:Civil law:• BGB (German Civil Code)cl. 633 Contractor‘s duty of warranty;removal of defectscl. 276 Responsibility for one‘s ownconductcl. 278 Responsibility for personsemployed in performing anobligationcl. 459 Liability for defect of qualitycl. 823b Unlawful actions• Produkthaftungsgesetz (ProductLiability Act)cl. 3 Identification of a defect/Competence• Gerätesicherheit (Safety ofEquipment)cl. 3 Code of practice• AVBEltV (General Conditions forElectricity Supplies to StandardrateCustomers)Duty to observe the standardsStatutory instruments:• Gewerbeordnung (Trade andIndustry Act)cl. 24 Installations requiring monitoringcl. 120a Mortal danger and otherhealth risks• VOB (Contract Procedures forBuilding Works)cl. 3 Suspected defectscl. 4/2 Responsibility/Code of practicecl. 4/3 Written notification of concernsBasically, a person undertaking workis always liable for ensuring that hiswork is free from defects. Thedecisive starting point from which toestablish whether work is free fromdefects is adherence to the generallyaccepted codes of practice.W1296380000 – 2012/2013W.43

The basics of lightning andsurge protectionSummary of standards and regulationsSurge protectionstandards and regulationsIn the case of national and international standards and specifications on the same subject, the document with the widest scopetakes precedence (e.g. international “IEC”, European “CENELEC” or “CNC”, national (Germany) “DIN VDE” or Austria“ÖVE” (Similarto TÜV Germany, also valid in Austria.)).IEC EN VDE othersEN 60728-11 Cables distribution systems for television and sound signals –Part 11: Safety requirementsIEC 60364-5-53 HD 60364-5-53 VDE 0100-534Electrical installations of buildings – Part 5-53: Selection and erection of electrical equipment– Isolation, switching and control – Part: 534: Surge protection deviceIEC 60364-5-54 HD 60364-5-54 VDE 0100-540 Electrical installations of buildings – Part 5-54: Selection and erection of electrical equipment– Earthing arrangements, protective conductors and protective bonding conductorsIEC 60664-1 EN 60664-1 VDE 0110-1 Insulation coordination for equipment within low-voltage systems –Part 1: Principles, requirements and testsIEC 61241-14 EN 61241-14 VDE 0165 Teil 2 Electrical apparatus for use in the presence of combustible dust –Part 14: Selection and installationIEC 60079-11 EN 60079-11 VDE 0170 Teil 7 Explosive atmospheres – Part 11: Equipment protection by intrinsic safety “I”IEC 62305-1 EN 62305-1 VDE 0185-305-1 Protection against lightning – Part 1: General principlesIEC 62305-2 EN 62305-2 VDE 0185-305-2 Protection against lightning – Part 2: Risk managementIEC 62305-3 EN 62305-3 VDE 0185-305-3 Protection against lightning – Part 3: Physical damage to structures and life hazardIEC 62305-4 EN 62305-4 VDE 0185-305-4 Protection against lightning – Part 4: Electrical and electronic systems within structuresIEC 60529 EN 60 529 VDE 0470-1 Degrees of protection provided by enclosures (IP code)IEC 60099-1EN 60099-1 VDE 0675, Teil 1 Surge arresters – Part 1: non-linear resistor type gapped surge arresters for A.C. systemsDIN IEC 37-197-CDVIEC 60099-4 EN 60099-4 VDE 0675, Teil 4 Surge arresters – Part 4: Metal-oxide surge arresters without gaps for A.C. systemsIEC 60099-5 EN 60099-5 VDE 0675, Teil 5 Surge arresters – Part 5: Selection and application recommendationsIEC 61643-1 EN 61643-11 VDE 0675-6-11 ÖVE SN 60 Teil 1+4 Low-voltage surge protective devices – Part 11: Surge protective devices connectedto low-voltage power systems – Requirements and testsVDE 845, Teil 1Protection of telecommunication systems against lightning, electrostatic dischargesand over-voltages from electric power installations; Provisions against over-voltagesIEC 61643-21 EN 61643-21 VDE 845-3-1 Surge protection devices for low voltages – part 21: Surge protective devices for use intelecommunications and signal conditioning networks - Performance requirements andtesting methodsIEC 61643-22 TS 61643-22 VDE V 845-3-2 Surge protection devices for low voltages – part 22: Surge protective devices for use in telecommunicationsand signal conditioning networks - Selection and application strategiesIEC 60038 HD472 VDE 0175 IEC standard voltagesKTA 2206, 06.92Lightning protection standard for nuclear power plantsVDE publication 44Lightning protection systms, expanations to DIN 57185/VDF 01 85, published by VDEDIN-VDE publication Publication No. 519; Lightning protection systems 1,external lightning protection, published by VDELightning protection systems 1, external lightning protection, published by VDEDKE publicationNo 520ÖVE 8001 §18Publication No. 520; Lightning protection systems 2,internal lightning protection, published by VDEProtection against lightningWDIN IEC 88/117CD(VDE 0127 Part 24):2000-06IEC 61400-24VdS 2010:2005-07 (03)SPD for telecommunication selection u.application principlesWind power facilities - part 24: Lightning protection for wind turbinesWind turbine generator systems, Lightning protection for wind turbinesThe above list is not exhaustive.W.441296380000 – 2012/2013

Summary of standards and regulationsThe basics of lightning andsurge protectionRisk-based lightning and surge protection, guidelines for damage prevention; VdS damage prevention in the German General Association of Property Insurers Association (GDV)VdS 2031Lightning and surge protection for electrical facilitiesVdS 2019Surge protection in residential buildingsVdS 2258Protection against surge voltagesVdS 2569Surge protection for electronic data processing computers/equipmentDIN EN 61647-321(VDE 0845-5-2):2003-02DIN EN 61647-331(VDE 0845-5-3):2004-03DIN EN 61647-341(VDE 0845-5-4):2002-11VdS 3428: 2005-04Components for surge protection devices for low voltage, avalanche breakdown diodes(ABD) provisionComponents for surge protection devices for low voltage metal oxide varistors (MOV)provisionComponents for surge protection devices for low voltage suppressor diodes (TSS)provisionDirectives for electrical equipment – surge protection devices (arresters)UTE C 61-740-51French standard for testing SPDs in photovoltaic applicationsDIN CLC/TS 50539-12Surge protection for low voltage – Surge protection devices for special applicationsincluding DC – part 12: Selection and application strategies – Surge protection devices foruse in photovoltaic installationsprEN 50539-11Preliminary standard for testing SPDs in photovoltaic applicationsThe above list is not exhaustive.W1296380000 – 2012/2013W.45

The basics of lightning andsurge protectionWW.461296380000 – 2012/2013