The 5SM3746-6KL: The 63 A rated current and 400 V AC rated voltage define the continuous load capacity — this RCCB handles a 63 A feed through a 4-pole block, which is common for a sub-distribution board or a large single-phase load group on a 3-phase system. The 500 mA residual trip threshold is not for personnel protection (that needs 30 mA or lower); it is for equipment protection or fire prevention on circuits with high natural leakage, such as long cable runs, VFD-fed motors, or industrial heaters. The Type A designation means it detects sinusoidal AC residual currents plus pulsating DC residual currents — the standard choice for most modern electronic loads that generate half-wave rectified leakage.
Snaps onto DIN rail and occupies 4 width units — 72 mm wide, 90 mm tall, 77 mm deep, with an installation depth of 70 mm. That 77 mm depth means it clears most 100 mm deep enclosures, but check your gland plate clearance if the cabinet is shallow. Wire range: 1.5 to 25 mm² solid or stranded. Mounting position is any, supply can come from top or bottom.