Why Change a Good Thing?

摘要

Prior to and including the 1956 National Electrical Code (NEC) there was a limit of nine conductors in a raceway, except when used for control, stage lighting, elevators, and similar uses. In the 1959 NEC, a proposal submitted by a Technical Sub Committee on Raceway Fill and Heating of Conductors, and based on a UL Fact Finding Report, was accepted, and the limit of nine conductors in a raceway was removed.