This is a Vigi add-on module for ComPact NSX 100/160/250 that provides a residual current alarm. It is used for 3-pole circuit breakers. The operating voltage ranges from 200 to 440 VAC at 50/60 Hz. The differential current sensitivity is adjustable from 30 mA to 30 A. It is installed directly on the device connection terminals and issues an alarm in the event of a fault due to residual current without tripping. This Vigi add-on module is powered internally by the voltage of the distribution network, even when supplied by only 2 phases. It complies with the IEC 60947-2 standard, Annex B.