UL 1053

These requirements cover ground-fault current sensing devices, relaying equipment, or combinations of ground-fault current sensing devices and relaying equipment or equivalent protection equipment for use in ordinary locations that will operate to cause a disconnecting device to open all ungrounded conductors at predetermined values of ground-fault current, in accordance with the National Electrical Code, ANSI/NFPA 70.

These requirements cover equipment intended for use in circuits that are solidly grounded and that operate at 150 volts, or more, to ground, but not more than 600 volts phase-to-phase.1.2 revised and separated into 1.3 and 1.4 October 27, 1999

These requirements do not cover equipment intended to be powered from circuits operating at more than 600 volts.1.3 relocated from 1.2 October 27, 1999

These requirements do not cover ground-fault circuit-interrupters.1.4 relocated from 1.2 October 27, 1999

These devices are intended to operate with shunt-trip circuit breakers, electrically tripped bolted pressure contact switches and the like that constitute the disconnecting means.

A Class I ground-fault protection device is one that does not incorporate means to prevent opening of the disconnecting means at high levels of fault current and is intended for use with the following: