TEN350 The waveform that hijacked the IEC lightning standards

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 was 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 an 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.

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