Discussion on “lightning-arresters,” at Milwaukee, Wis., May 29, 1908

H. C. Wirt: Line to line discharges have not been admitted by some authorities, and for that reason I present additional data to that presented by me three or four years ago, in a paper before the Institute. In Fig. 21, the four papers represent the arrangement of the arresters; the lower one, the multiplex connection. You will notice the lower one is not punctured. The other punctures were made by voltage effects from line to line. As Mr. Osgood has said, the consensus of opinion expressed here to-day is that the very severe discharges are from line to ground; that wherever the record-pipers show a large hole, the voltage stress was between line and ground. Whether this was part of the actual lightning stroke going into the station and then to ground, we do not know. In order to limit the dynamic effect the gaps might be increased or the character of the metal improved, and therefore a great many tests were made on non-arcing metal.