Overvoltage Protection of Low Voltage Systems

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The book ‘Overvoltage Protection of Low Voltage Systems’ By Doctor Mr. Peter Hasse

I remember the book ‘Overvoltage Protection of Low Voltage Systems’ By Peter Hasse gave me fundamental knowledge when I was a young man who involved in the surge protection field in December 2006.

Have the honorto read this book, free download this book of English and Chinese edition.

Overvoltage Protection of Low Voltage Systems By Peter Hasse
低压系统防雷保护 (第二版)

Dr. Peter Hasse, ‘Mr. 10/350’ Godfather of the 10/350 waveform.
In the world of lightning protection, Peter Hasse is a living legend.

Born in 1940, he studied electrical and power engineering at Berlin Technical University, graduating in 1965. He then worked as a research assistant at the local Adolf Attias Institute for High Voltage Engineering until receiving his doctorate there in 1972. A few months later he joined the R&D department of DEHN + Sohne. There he was instrumental in developing a self-extinguishing air-gap of enormous capability and a new theory to justify its use in lightning protection. This was called at the time the “new” 10/350 waveform. In 1981, Dr. Hasse became Dehn’s Managing Director and remained so until his retirement in 2004. Since 2002 he’s been on the Board of Directors of a German test laboratory: GHMT AG Bexbach.

Shortly after retiring from Dehn, Dr. Hasse was awarded the prestigious Order of Merit of the Federal Republic of Germany.

At the 2005 awards ceremony Hasse was glorified for turning Dehn + Sohne (a small family-owned company manufacturing lightning rods) into a major international player in the lightning protection market. At the same time he was praised for the “significant role” he had played in influencing the national and international standards-making bodies that dealt with lightning protection.

The praise was not exaggerated. Every account of Hasse’s accomplishments contains the same line: “He has played a significant role in national and international standards-making bodies in the area of lightning protection.” Just exactly how “significant” had been difficult to determine because up to now the full extent of his actions in this arena had not been fully cataloged.

For over 20 years, while running Dehn, Hasse was concurrently promoting his new theories and devices to standards writers and getting them written into standards for mandatory use. In 1975, he became a founding member of the VDE (German standard organization) Committee on Lightning Protection (ABB) and shortly thereafter was running it (according to Prof. Dr. Kawamura, President of Japan’s I.E.I.E.) In 1977 Hasse joined the DKE (Germany’s representative to the IEC and CENELEC) providing him the springboard needed to become the German spokesperson to both IEC/SC37A “Low Voltage Surge Protective Devices” and IEC/TC81 “Lightning Protection” (which he joined at its inception.)

Move through the Hasse pages that follow (accessible through the links below) and you’ll find that it wasn’t Thor nor any other god of lightning who gave life to the 10/350 waveform. Neither was it CIGRE nor even the acclaimed Swiss researcher, Dr. Karl Berger.

Lift the veil and one finds the true source of the 10/350 waveform to be none other than our own Dr. Peter Hasse.

THE HASSE 10/350 CHART – Birth of the 10/350 waveform

Dr. Hasse unveiled his grandiloquent “10/350” idea on page 46 of the first German edition of his book “Overvoltage Protection of Low Voltage Systems: Using electronic equipment even in the face of direct lightning strikes” “Überspannungsschutz von Niederspannungsanlagen – Einsatz elektronischer Geräte auch bei direkten Blitzeinschlägen”, (Verlag TOV Rheinland GmbH, Koblenz,) published in 1987. The chart is shown below.

Roll your mouse over the above chart to activate links giving details of relevant aspects. A first look shows it features all 5 of IEC 62305’s 10/350 parameters (highlighted). A second look shows Hasse is attributing these parameters to a German standard “VG 96901.” A check with DIN (the German Standards Institute) disclosed that VG96901 was never a valid standard. It was a “prestandard” without authority or precedence.

But that is of but little import since Hasse states in the text introducing this chart that he personally created it. And, indeed, the sole citation (shown on the bottom of the chart as /42/) refers to a “guideline” authored by Hasse in 1982.

The accompanying text broadly announces (possibly for the first time) that this chart represented the parameters of direct lightning strikes, and that spark gap surge protectors were required “without exception” to be used to protect electrical and particularly electronic information technology systems. (p. 46-47)

Just months after the publication of his book Dr. Hasse brought his 10/350 Chart to the IEC TC 81 meeting in Japan (June 1988) to give structure to his lecture on the “true waveform of direct lightning.” Here the indoctrination included the parameters from the Hasse 10/350 chart (200kA, 100 C, 10 MJ per ohm) plus showed dozens of photos of his Dehn spark gap arrestors. Here’s the slide of the Hasse 10/350 Chart extracted from that presentation. You can see he proudly cites himself (and his 1987 book) as the source of the chart.

In those days Hasse hadn’t yet begun laying responsibility for the 10/350 waveform at the door of Berger & CIGRE. That was to come later.

His 1987 book (where the chart first appeared) contains 83 references and citations but there is no mention of either Berger or CIGRE.

That is because, as shown in the above data, the 10/350 waveform came from Dr. Peter Hasse.

IEC 62305 LIGHTNING PROTECTION ZONE CONCEPT (effective scientific tool or public relations hype?)
LPZ – Lightning Protection Zone Concept: What is it?

Lightning Protection Zones (or LPZs) are central to the IEC 62305 approach to lightning protection. The idea is to limit lightning-induced current and voltage surges entering a structure by dividing the structure into a succession of risk zones (nested inside each other.) Through careful use of shielding techniques and SPDs the effects of lightning hitting the outer zone are meant to be mitigated before they can reach the inner zones. At least that is the theory. According to IEC 62305-4 (Sect. 4.1) this LPZ concept is the basis of all lightning protection.

How effective is the IEC 62305 Lightning Protection Zone concept?

The IEC-branded LPZ concept has been in widespread continuous use for 20 years. Yet when Rakov and Uman searched, they were unable to find a single study containing statistical evidence confirming its effectiveness (“Lightning, Physics and Effects, Cambridge University Press” page 591). A further search in 2013 also turned up null. Apparently no study has ever vouchsafed the workability of the IEC 62305’s LPZ system.

On the face of it, the LPZ system seems a logical approach to surge protection. So why, in 20 years, have there not been studies documenting its success? That question led to a deeper look into its evolution and application.

E.F. Vance: Creator of the Lightning Protection Zone Concept

The original LPZ concept was created by an American, E.F. Vance, of the Stanford Research Institute in Menlo Park, California. Vance introduced it in 1977 in a paper entitled “Shielding and Grounding Topology for Interference Control.” On the left is a diagram extracted from that paper showing Vance’s risk zones. By “grounding” the outside of each shield to the inside of the adjacent shield, Vance sought to control the effect of external surges entering a facility. He also realized the need to limit the surges on the power and data lines entering the structure.

Zone 0 was the moniker Vance gave to the external environment subject to lightning strikes. Zones 1 & 2 he assigned to the areas inside the structure.

Vance LPZ system co-opted by Dr. Peter Hasse

 Dr. Hasse appropriated Vance’s idea and transformed it into a book he titled: “EMC-Lightning Protection Zone Concept” (co-authored by Peter Hasse & Johannes Wiesinger and published by Pflaum Verlag in 1993.)

On the right you can see Vance’s LPZ diagram as it appears, unchanged (except for the addition of the German translation) on p. 52 of Hasse’s book. Vance’s original structure and terminology were retained in the Hasse adaptation: Zone Zero continued to represent the area outside the structure; Zones 1 & 2, the areas inside the structure.

Unfortunately Dr. Hasse used the LPZ system to forward his 10/350 waveform idea by insinuating the idea that all lightning impulses in Zone Zero should be characterized by a 10/350 waveform. Click here to see how Hasse’s 1993 LPZ book injected the 10/350 waveform into the LPZ concept.

In so doing, he nullified the potential success of what might have become a very workable approach to lightning protection. The complications caused to the LPZ system by the 10/350 waveform include the defects of the spark gaps, plus the quagmire of “SPD coordination” both of which are dealt with elsewhere on this web.

Accounts of some of the damage caused to equipment and installations being “protected” according to this 10/350-LPZ system can be found elsewhere on this web.

LPZ Migration – From Hasse’s book to IEC lightning protection standards

By the time his LPZ book was published in 1993, Dr. Hasse was a formidable presence in the IEC lightning protection committee, TC 81. It took him less than two years from the publication of that book to get his LPZ concept imported in its entirety into the IEC 61312-1 standard.

On the left is the LPZ diagram from IEC 61312-1. The 10/350 waveform was made an integral part of it. Click here to see the Hasse 10/350 lightning parameters as they appeared in the 61312-1 standard.

Thus can be seen, that in a single flash of lightning, Dr. Hasse succeeded in getting both his 10/350 waveform AND his LPZ concept imported into the IEC international lightning protection standard.

The next step was migrating them into the IEC 62305 standard. The story of how he managed that can be found here.

To summarize, Dr. Peter Hasse is not only to be credited with giving birth to the 10/350 waveform, but also to creating the LPZ system being used today in all IEC lightning protection standards.

LPZ In daily use: curtailing lightning or curtailing competition?

The most recent LPZ diagram from IEC 62305 is shown on the right. Its purpose is ostensibly to mitigate the impact of incoming lightning. But some believe the function of the IEC LPZ system has more to do with stipulating which structural and surge protective devices are to be deemed “proper” and thus regulating their use. For example, IEC 62305 insists that direct lightning must be characterized by a 10/350 test waveform, and therefore only spark gap “lightning arrestors” may be used in Zone Zero. Other types of SPDs are banned.

There are three major problems with this approach. The first two are technical and are documented throughout this web, namely: 1) the 10/350 waveform does not represent actual lightning, and 2) the spark gap “lightning arrestors” have many intrinsic flaws.

The third major problem could be a legal one. The way the LPZ system has been implemented in standards may constitute a violation of the European Union Competition Law. (See FAQ page.)


In case anyone is taking this “personally” please accept the fact that this website is not meant to be a rant on any particular person, company, or committee. Its entire object is to improve the state of lightning protection. And though it may take courage to stand up and speak, it takes just as much courage to sit down and listen.

THE HASSE 10/350 CAMPAIGN – A river of books, articles, and presentations: 10km wide / 350km long

During the 80s and 90s (according to a Dehn website) Hasse, his collaborator J. Wiesinger, and other Dehn staff and cohorts wrote or participated in literally hundreds of papers, books, presentations to international conferences, exhibitions, and seminars. One “old-timer” estimated that over ten million dollars were spent on this campaign. The underlying message in most of these issues and presentations echoed Hasse’s 1987 book: “direct lightning is represented by a 10/350 waveform; only spark gap surge protectors capable of passing a 10/350 waveform test should be used to protect against direct lightning.”

A partial list may be found here.

Hasse promoted his 10/350 Chart to TC-81 in his 1988 “History of Lightning Protection” presentation at the IEC TC-81 Memorial Meeting in Japan.  The chart also appeared in the later editions of his 1987 book.     It can be found in articles such as “Neues aus der Blitzschutztechnik,” etz, Vol. 108, pp. 612-618, also published in 1987 and EMV-Blitz-Schutzzonen-Konzept, co-written with J. Wiesinger and published by VDE Verlag in 1994.  It is featured in Hasse’s 1998 book “Overvoltage Protection of Low Voltage Systems” and its later editions.

Equivalency factors

 In 1999, Dr. Hasse approached the Surge Protective Devices Committee of the IEEE and asked, as an eminent representative of TC 81, to be invited to the IEEE’s SPD Committee spring 2000 meeting for the purpose of giving a presentation on the “origin, relevance and validity of the 10/350 μs waveform.” On Sept. 29, 1999 the SPD Committee accepted his offer, and the following May the meeting was held in St. Petersberg, Florida. Dr. Hasse showed up hoping to impress upon the IEEE attendees the importance of using the 10/350 waveform to replicate the first stroke of direct lightning. In passing he mentioned a 10:1 scaling factor for converting the 10/350 waveform to 8/20, but placed little stress on it. Hasse met with little success in that meeting and the following year sent his Dehn VP (Richard Chadwick) to try again. Preaching the same message, using identical charts and the same claims concerning the parameters of positive lightning, this presentation gave more emphasis to the scaling factor: “Might there not exist a scaling factor by which Spark Gaps and MOV SPDs could be compared?”

As a first suggestion Chadwick threw out a factor of “30.” This meant for a MOV SPD tested with an 8/20 waveform to be considered in the same class as a Spark Gap tested with a 25kA 10/350 μs impulse, the MOV SPD would need to be rated at 750kA. Dr. Chadwick fully realized how unrealistic that was and at the end of his presentation concluded that “universal scaling factors must not be used” but that only spark gap protectors were suitable for installation at service entrances.

Strangely enough, notwithstanding Chadwick’s actual message, it started some IEEE folks thinking this approach might be a way to achieve a reconciliation with the IEC on this subject. Various figures were batted around and finally “10” was briefly adopted by the IEEE.

Hasse remained firm. A Chadwick presentation later that same year insisted on the equivalency multiplier of 25. See that slide here.

All this talk of “equivalencies” prompted Francois Martzloff, of the IEEE SPD committee, to commission a study to determine whether a “consensus-derived compromise ‘equivalency’ of the two waveforms” could be achieved “via a simple multiplying factor.” A check of the math and taking into account the various factors involved found the endeavor to be “unrealistic.” You can read the entire document here. By 2006 any serious talk about “equivalency” factors had ended. This is confirmed in IEEE Std C62.62 (2010) where no 10/350 waveform is allowed.

In Hasse’s articles and presentations one can imagine the struggle of conflicting urges: On the one hand, his genuine urge to engage in technical issues and on the other, the compulsion to commercially promote his spark gap products. One cannot help commenting that in his technical presentations and books he could rarely refrain from showing pictures of his Dehn spark gap protectors and bragging how well they protected against “direct lightning.”

This could also be seen as an artful use of the law of supply and demand: Hasse had the supply of spark gap devices. All that was needed was for the IEC to provide the “demand.” As a business plan, it was brilliant.

DR. HASSE, TC81 & THE IEC 62305 SERIES – the hijacking of a standard
10/350 Milestones and Zenith: The IEC 62305 lightning protection series

In 1993 the release of IEC 61024-1-1 marked a giant step forward in the international arena for the Hasse10/350 waveform. Its lightning parameters for impulse current, charge, and specific energy were lifted straight out of the Hasse chart. But it was in 1995 that Hasse finally saw his hard work come to fruition when TC 81 released IEC 61312-1 naming, legitimizing and giving authority to the Hasse10/350 waveform. From then on everybody would KNOW that direct lightning could only be characterized by a 10/350 waveform. The party in Neumarkt that night must have been gleeful.

The second milestone was getting the 10/350 waveform incorporated into IEC 61643-1.

But its zenith was unquestionably the day when the Hasse 10/350 waveform was inserted (in its entirety) into the IEC 62305 lightning protection series. And there’s an interesting story associated with that.

What was arguably Hasse’s most ambitious and most audacious ploy in forwarding his 10/350 waveform is eloquently described by Ernst Landers in IEC Document 81/195/INF dated 2002.07.05 entitled TC 81 WG 3 Convenor’s Report? Ernst U. Landers, by then a long-time Hasse collaborator, was the actual TC81 WG3 Convenor in 2002. But Dr. Hasse was also present at the TC81 meeting being discussed (in Firenze, Italy October 17, 2001) and was assuming the role of “Deputizing Convener.” We don’t know exactly what a “deputizing convenor” is, but the document makes it clear that Hasse was the one running the meeting which was dealing with the subject of how to incorporate the “SPD requirements” and “Application guide” from IEC 61312-1 into the work-in-progress IEC 62305 series of standards. This would, ipso facto, have included both the Hasse 10/350 chart parameters & LPZ concept.

Under Hasse’s tutelage, TC 81 WG3 had already decided to fully integrate the IEC 61312-1 Hasse data into 62305. Quoting here from the convener’s report, because the technical content of 61312-1 had already been “discussed and accepted unanimously in WG3, the convenor offered, to integrate editorially these five parts (of IEC 61312-1) into the draft IEC 62305…” His offer was of course readily accepted. We have to agree this was a good move from Dr. Hasse’s viewpoint–getting the Hasse 10/350 waveform and LPZ concept written into the new 62305 series in an unadulterated form was far too important a task to be left to the vagaries of “committee action.” According to the report, the “editing work” was completed and the resultant document was sent to all members of WG 3 giving them 1 month to respond. When, after one month, NONE of them had responded, the actual convener, Dr. Landers, naturally, declared a “consensus” had been reached and sent the document to Dr. Lo Piparo (Secretary of TC 81) who got it published as a New Work Item proposal. This pushed it on its way to eventually becoming a full standard.

Introducing IEC 62305 to the world

Long before the 62305 Standard was completed, Hasse took it upon himself to introduce and gain acceptance for it. He was the first to bring it to the world’s attention with his paper “New Standards for Protection Against Lightning–New Series 62305” presented at the VII SIPDA in Curitiba, Brazil in 2003.

Broadcasting his theories and getting them accepted were tasks Hasse took very seriously. In 1994 at the 22nd International Conference on Lightning Protection in Budapest his article “Principle for an Advanced Coordination of Surge Protective Devices in Low Voltage Systems” for the first time used the catchphrase: “primary threat from lightning was the 10/350 waveform.” Guaranteed to attract attention, this was later incorporated into the 62305 Series. His article “A future-oriented principle for the coordination of arresters in low-voltage systems” (etz. magazine Issue 1, pp. 20-23, 1995) was aptly named. Dr. Hasse’s prescient vision had allowed him to exactly predict IEC 62305’s 10/350 lightning protection parameters more than 10 years before the fact.

THE 10/350 CAMPAIGN CONTINUES – with a new twist
The campaign continues – with a New Twist

Dr. Hasse’s personal 10/350 campaign is apparently not quite over. In 2010 he wrote Chapter 7 of a book entitled “Lightning” published by the Institute of Engineering and Technology, London, UK. In Hasse’s prose the 10/350 drum beat once more: “At the boundaries of LPZ 0… SPDs must be used, which are capable of discharging considerable partial lightning currents… These SPDs are called lightning current arresters (SPDs class I) and are tested with impulse currents, waveform 10/350μs.” As usual he included lots of photographs of Dehn spark gap protectors.

But this time he went one step further. He “recognized” the ability of a MOV surge protector to stand in place of a spark gap “if the specified nominal discharge current 8/20μs was at least 25 times the specified 10/350μs discharge current.” For example, for a MOV SPD to pass a test specified for 25kA 10/350μs, it would have to be subjected to an impulse current of “at least” 625kA 8/20μs. Does anyone have any idea where Dr. Hasse comes up with this stuff?

The Hasse politically correct equivalency factor has now gone from 10 to 30 to zero. Then up to 25 and now to “at least 25.” (see the earlier page in this series.) We suppose you could say that Dr. Hasse was in favor of an equivalency factor both before and after he was against it… He even created a new illustrative chart for inclusion in the 2010 book. You can see it here to the right. Who knows, if somebody doesn’t do something quick, it’s likely that the next time you see it will be in the next re-write of the IEC 62305 Series.

The Corporate Campaign Continues

Dehn and Sohne’s 30-year corporate campaign to promote the 10/350 waveform continues to this day. The following quote from the Dehn website in August 2013 rejects any idea of an equivalency factor. It says: “DEHN believes it is necessary to test with the actual 10/350 μs waveform…only testing with the 10/350 μs waveform is truly representative of performance for protection against direct lightning strikes.”


In case anyone is taking this “personally” please accept the fact that this website is not meant to be a rant on any particular person or company. Its entire object is to improve the state of lightning protection. And though it may take courage to stand up and speak, it takes just as much courage to sit down and listen.

THE 10/350 WAVEFORM -The rest of the story
There’s more to 10/350 than the 10 and the 350

In the “Hasse 10/350 waveform Chart” shown elsewhere you can see the two parameters of the 10/350 signature highlighted in pink: T1 = 10μs and T2 = 350μs. But the “10/350 waveform” has always been a misnomer. Look again at Hasse’s Chart and you will see it includes three other parameters (highlighted in yellow): Peak current = 200 kA; Charge (Q) = 100 coulombs; and W/R = 10MJ / Ω.

For over 30 years the “10/350 waveform” was always a package deal. It always included those 5 parameters. And the value of peak current (kA) was always twice the value of the charge (coulombs). Why? Maybe because all 5 of those parameters were needed to lock-in the use of the spark gap surge protectors? The reader can decide. Meanwhile, the CIGRE 2013 report lends no credibility to these parameters or any such relationship between parameters.

Below you have Table from the most recent IEC International Lightning Standard (IEC 62305-1). This is the foundation on which the entire IEC lightning protection standard is built. Does anything look familiar? (Roll your mouse over it to see where the key parameters originate.)

The lamb and the wolf.

CIGRE’s 2013 Technical Brochure 549 has made it clear that CIGRE can no longer be blamed for the highlighted parameters in the above chart, including the 10/350 waveform itself. Do you recall the fable of the lamb and the wolf? Under the wool of the IEC 62305 lightning protection standards you will find only the hide and claws of Dr. Peter Hasse.

The time has come for the international lightning protection community to confront that fact and delete the mandatory use of those parameters from standards.

Conflicts of Interest and Accountability

We make no accusation of impropriety. We don’t need to. We only state what occurred. Even if there had been wrongdoing, it would have long since been forgiven by the relevant statutes of limitation. It is the future that is important, not the past.

Conflict of interest

It’s hard not to speculate about the potential conflict of interest inherent in this situation. Was it OK for the Managing Director of a commercial enterprise such as Dehn and Sohne, to be inventing devices by day while, by night, assuming such grand influence over international standards committees that they would specify mandatory use of those devices?

CIGRE’s US National Committee employs an Ethics Program with a no-nonsense approach to such behavior: “The US National Committee’s policy requires that all members avoid actual or apparent conflicts of interest. An actual conflict is a personal interest that is likely to cause an independent observer to conclude that an individual conducting the US National Committee business cannot make an unbiased decision, give…unbiased advice, exercise independent judgment, or be objective with respect to…technical results. An apparent conflict of interest occurs when personal interests are likely to cause an independent observer to question whether an individual conducting business on the US National Committee’s behalf can do so fairly.”

While recognizing that standards committees must often rely on the support of commercial enterprises to get their work done, it would seem that some kind of oversight or watchdog function was loudly missing in this case.


If you’ve ever read an IEC standard you’ll immediately see a practice which can all but guarantee to promote lack of responsibility and lack of accountability on the part of standards writers. We refer to the fact that IEC standards never show who authored them.

Whoever writes a standard, their names had better be on it so they can be held accountable if a problem turns up somewhere down the road. And not only a name. To that must be added the person’s affiliations and who’s paying him to attend the meetings. Any concealed connections should make a standard writer liable to civil and/or criminal prosecution.

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