The Schneider Electric A9R26492 is a 4-pole residual current circuit breaker (RCCB) from the Acti9 family, rated 125 A with 500 mA earth-leakage sensitivity and Type A protection. The 125 A rating makes it a main-switch or heavy-feeder RCCB for commercial or industrial sub-distribution, not a final-circuit device. The 500 mA sensitivity is a selectivity threshold: it sits upstream of 30 mA RCCBs so that a downstream fault trips the local device first, keeping the main board live.
Rated breaking and making capacity is 1250 A at both 400 V and 230 V, per IEC/EN 61008-1 and -2-1. That is the short-circuit withstand of the RCCB itself — not a high-breaking MCB, but adequate for the fault levels typically seen downstream of a 125 A feeder in a commercial panel. The rated insulation voltage (Ui) and operational voltage (Ue) are both 400 V AC 50 Hz, confirming it is a 3-phase / 4-wire device (400 V line-to-line). Mechanical durability is 5000 cycles; electrical durability is 2000 cycles. That is a standard duty rating for a distribution RCCB — not intended for frequent switching, but fine for its role as a protective device that operates only on fault or during maintenance isolation. The toggle control and red/green trip indicator give clear local status; the padlock provision lets you lock it off for safe downstream work. Terminals accept up to 50 mm² rigid or 35 mm² flexible cable — enough for the 125 A feed. Tightening torque is 3 N·m; strip length is 11 mm. The tunnel-type terminals take two cables per pole up to 16 mm², useful for looping through to another device.
Mounting and enclosure fit
The 4-pole body takes 8 x 9 mm pitches (72 mm wide), 86 mm tall, 76 mm deep. IP20 on the terminals, IP40 inside a modular enclosure — standard for distribution boards.