The Schneider Electric A9Z64491 is a 4-pole residual current circuit breaker (RCCB) from the Acti9 iID family, rated 100 A at 400 V AC 50 Hz with a 300 mA earth-leakage sensitivity. The Type B-SI (Super Immunised) characteristic means it detects smooth DC fault currents and AC pulsating currents, and it's designed to ignore nuisance tripping from high-frequency harmonics — exactly the kind of load you get from variable-speed drives, photovoltaic inverters, and lift controllers. That's the application the spec sheet calls out: photovoltaic, 3-phase speed drive, lift.
The 100 A rated current (In) and 400 V rated operational voltage (Ue) tell you this RCCB handles the full incoming feed for a sub-distribution board or a large machine supply. The 300 mA sensitivity is a common choice for protection against fire risk from earth faults — it's less sensitive than 30 mA (which is for personal shock protection), so it won't trip on the normal leakage of a drive's EMC filter or a long cable run. That's why the Type B-SI matters: it stays stable where a standard AC-type RCCB would nuisance-trip. The insulation voltage (Ui) is 500 V, and the overvoltage category is IV — that's the highest category for mains distribution, meaning it's rated for the transient overvoltages you get at the service entrance or main panel. It's certified to IEC 61008-2-1 and IEC/EN 62423, which are the standards for RCCBs with immunity against unwanted tripping (the SI part). Quality labels from VDE, NF, IMQ, and KEMA mean it's accepted across European and international markets without additional testing.
Installation details for the panel builder
Terminals accept double conductors: front terminals take 1 to 35 mm² rigid or 1 to 25 mm² flexible (with or without ferrule); rear terminals take 1 to 25 mm² rigid or 1 to 16 mm² flexible. Wire stripping length is 14 mm. The 8/20 µs impulse withstand of 3 kA (per EN/IEC 61008-1) means it survives surge events from lightning or switching transients without damage.