The Schneider Electric A9N21511 is an add-on residual current device from the Prodis range, designated Vigi TG60. It is a 4-pole (4P) unit rated at 40 A with a 30 mA earth-leakage sensitivity, Type AC (sensitive to sinusoidal AC residual currents only).
Rated at 400 V AC phase-to-phase at 50 Hz, this device is sized for standard three-phase distribution in European-style panels. The 30 mA sensitivity provides personnel protection against direct contact, while the Type AC classification means it trips on sinusoidal AC residual currents only — not suitable for pulsating DC or smooth DC fault currents (those require Type A or Type B). The instantaneous trip time means no intentional delay for selectivity; it clears faults as fast as the internal mechanism allows. Terminals accept cable from 0.75 to 16 mm² rigid or 0.33 to 10 mm² flexible, with a tightening torque of 2 N·m and a strip length of 13 mm. The 9 mm pitch occupies 6 pitches (54 mm width), fitting standard DIN-rail spacing.
The A9N21511 complies with IEC 60947-2 (low-voltage switchgear and controlgear) and EN 61009-1 / EN 61009-2-1 (residual current operated circuit-breakers with integral overcurrent protection for household and similar uses). Local ON/OFF indication is provided on the device.