The Siemens 5SU1644-7RC63 is a 4-pole RCBO rated 63 A with C characteristic and Type A residual current detection at 300 mA, occupying 7 module widths on a DIN rail. The C characteristic means the magnetic trip operates at 5 to 10 times rated current — typical for motor and lighting circuits where moderate inrush is expected. Type A residual detection catches pulsating DC fault currents, not just sinusoidal AC, so it covers half-wave rectified loads like switching power supplies and variable-speed drives.
At 7 module widths (roughly 126 mm on a standard 18 mm/module DIN rail), it fits a standard distribution board or sub-panel. The C characteristic and 63 A rating make it suitable for final subcircuits supplying mixed resistive and inductive loads up to that current. The 300 mA Type A residual element provides earth-fault protection for equipment that generates pulsed DC fault currents — common in modern panels with electronic loads.