These requirements cover portable, stationary, and fixed uninterruptible power supplies (UPS) rated 600 volts or less ac or dc that are intended for installation in accordance with the National Electrical Code, NFPA 70.  During intended operation, the UPS allows the utility to deliver ac and dc power to the connected load through either the power conversion portion of the UPS or a bypass source. The power conversion portion of the UPS consists of a rectifier and an inverter.  During periods of power fluctuations, or power outage, or both, the connected load receives ac and dc power from the battery supply and power conversion portion of the UPS.

• Year of Declaration: 2003
• Reference: ANSI/UL 1778:1991
• Number of Pages: 139
• Code: GYS 218
• Version:
• ICS Number: 29.240.01