Abstract :
E. Beck (Westinghouse Electric and Manufacturing Company, East Pittsburgh, Pa.): The growth of statistical data, as accumulated in the widespread investigation described by Mr. McCann, provides more and more reliable information on what we may expect of lightning strokes. In fact, it is now possible to make valid estimates of the probability of lighting damage. The interpretation of these stroke data in terms of the performance of protective devices such as lightning arresters will require some further clarification and relation to similar data on the lightning currents discharged by arresters in service. At the University of Pittsburgh, one of the stroke-current measuring stations, types of lightning arresters have been connected in the stroke circuit during the several years covered by the study.