Discussion on “the grounded neutral,” at New York, October 11, 1907

In November, 1900, the Commonwealth Electric Company of Chicago in one portion of its territory put into commercial service the first extensive system of four-wire, three-phase distribution at 4000–2300 volts. This 60-cycle system was soon installed in all the company´s outlying and suburban territory, and has since grown to such an extent that the total length of three-phase or equivalent line of feeders to-day aggregates 525 miles, of which 55 miles is underground, the remainder overhead. The neutral of this 60-cycle system has always been connected solidly to ground.