Underwriters' Laboratories: Testing for Public Safety

A brief review of the history of Underwriters' Laboratories in the electrical field is presented, including the reasons and importance for its existence, how standards are developed and submittals are handled, and what factory follow-up services means to the manufacturer and the user under the new advance program concept. There is special emphasis on the progress in the development of requirements for and the recognition of high-interrupting capacity overcurrent devices, as well as related power control equipment, including switches, industrial control devices, busways, and related assemblies, such as panelboards and switchboards.