1 Scope

1.1 This Standard applies to Class A, single- and three-phase, ground-fault circuit-interrupters intended for protection of personnel, for use only in grounded neutral systems in accordance with the National Electrical Code (NEC), ANSI/NFPA 70, the Canadian Electrical Code, Part I, and Electrical Installations (Use), NOM-001-SEDE. These devices are intended for use on alternating current (AC) circuits of 120 V, 208Y/120 V, 120/240 V, 127 V, or 220Y/127 V, 60 Hz circuits.

Note: In Canada, the text “intended for protection of personnel” is excluded.

1.2 These requirements do not cover ground-fault circuit-interrupters intended for use in circuits served by a transformer having windings wholly insulated from each other.

1.3 This Standard applies to all Class A ground-fault circuit-interrupters. These Class A GFCIs are permitted to be integrated into other devices, in which case, besides complying with this Standard, these devices are to comply with the corresponding applicable Standard for the device in question.

1.4 This Standard includes minimum requirements for the function, construction, performance, and markings of ground-fault circuit-interrupters included in the scope.

1.5 This Standard is intended to cover only Class A GFCI devices.

1.6 This Standard also covers GFCIs of the self contained type that are intended for installation in a counter, such as would be suitable for installation in a kitchen or bathroom counter top.

Summary of Topics

This revision of the Standard for Safety for Ground-Fault Circuit-Interrupters, ANSI/UL 943, includes the following changes in requirements:

Expansion of Auto-Monitoring and End of Life Requirements to All Types of GFCIs

Addition of Requirements for Programmable Components

Improving the Auto-Monitoring Function of Permanently Connected Ground-Fault Circuit Interrupters