UL 943 covers ground-fault circuit-interrupters intended for use only in alternating-current circuits wherein one of the wires is grounded in accordance with the National Electrical Code. Devices complying to UL 943 are intended for use on 120 Vac or 120/240 Vac, 60 Hz circuits. 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. A ground-fault circuit-interrupter as covered by these requirements is a device whose function is to interrupt the electric circuit to the load when a fault current to ground exceeds some predetermined value that is less than that required to operate the overcurrent protective device of the supply circuit.
UL 943 provides requirements for ground-fault circuit-interrupters for use in accordance with the electrical installation codes of Canada, Mexico, and the United States. At present there is no IEC Standard for ground-fault circuit-interrupters for use in accordance with these codes. Therefore, this Standard does not employ any IEC Standard for base requirements.
Products Used in Testing:
Haefely
Haefely PIM 200 Current Impulse Module
The Haefely PIM 200 Current Impulse Module is used for testing overvoltage protection elements such as varistors, gas arrestors and avalanche breakdown diodes with clamping voltages up to 3 kV. Both impulse shapes 8/20μs and...