The international electrical units: a failure in standardisation?

The ‘international’ electrical units, initially defined by the International Electrical Congress of Chicago in 1893, represented a major step forward in international electrical standardisation. Yet they were flawed both theoretically and technically, were adopted inconsistently in different countries and were soon subject to criticism and revision. This paper addresses the extent to which the international units—notwithstanding their flaws—were in fact adequate for the needs of engineering, commerce and science at the time, and concludes that the practical position was actually very satisfactory. It also addresses how the international electrical units came in to being, in the context of alternative philosophies of the nature of the standardisation process—that it can be essentially central or local. The central influence on the international units was the series of international electrical congresses of the late nineteenth century, which I conclude were a highly unsatisfactory mechanism, responsible for many of the weaknesses in the resulting standards. In contrast, I argue that it was local influences, the networks of scientists and standards laboratories that defined and maintained the standards, which gave them their strength.