PT 60947-9-1 - TC 121/SC 121A/PT 60947-9-1

IEC 60947-9-1:2019 covers low-voltage arc quenching devices, hereinafter referred to as AQDs, which are intended to eliminate arc-faults in low-voltage assemblies (typically low-voltage switchgear and controlgear assemblies in accordance with the IEC 61439 series), by creating a lower impedance current path, to cause the arcing current to transfer to the new current path. This new current path is maintained until a short-circuit protection device (SCPD) interrupts the short-circuit current.
AQDs are installed in low-voltage assemblies, connected to the main circuit, preferably as close as possible to all primary power sources.
Their rated voltage does not exceed 1 000 V AC or 1 500 V DC.