ANSI E1.16 may be an inexpensive standard, but it's designed to eliminate expensive accidents. Manufacturers of ballasts for HMI-type lamps rated 6kW and above often use a common circular, three-pin connector for connecting the detachable power cable to the ballast. Most manufacturers use one particular pin of the three for the protective grounding connection, but until the publication of ANSI E1.16, there was no standard specifying which pin. Without such a standard, a manufacturer could easily decide to use a different pin for ground and the usual grounding pin for an ungrounded power conductor. This has happened, with the result that using one manufacturer's ballast with another's power cord led to an electrically hot ballast chassis. The use of a standard grounding connector assignment across the industry will help prevent this from happening.
(Ruth Rossington)
