What this 40 A B-curve MCB does on the panel
The Schneider Electric A9F06140 is an Acti9 iC60H miniature circuit breaker — one pole, rated 40 A, with a B-curve magnetic trip that triggers at 4 x In (±20 %). Thermal-magnetic trip element inside; no earth-leakage protection built in. Breaking capacity is the headline number here: 42 kA Icu at 12…60 V AC, 30 kA at 100…133 V, 15 kA at 220…240 V AC, and 20 kA Icu at 12…60 V DC. That 42 kA rating at low voltage is unusual for a 1-module (18 mm wide) MCB — it handles high-fault-current scenarios near transformers or in industrial sub-distribution without needing a current-limiting upstream fuse. The 10 000 A Icn at 230 V per EN/IEC 60898-1 covers the domestic coordination side. Depth is 78.5 mm, height 91 mm — standard compact footprint for a single-pole MCB. That terminal capacity is generous for a 40 A breaker — lets you land a larger feed conductor without a reducer.
Standards and compliance — what they certify
Dual-certified to EN/IEC 60947-2 (industrial) and EN/IEC 60898-1 (household / similar). That means the A9F06140 carries both the utilisation category A rating for industrial isolation and the Icn rating for domestic coordination. Overvoltage category IV (equipment at the origin of the installation, before the main distribution board). Suitability for isolation confirmed under both standards — you can safely use the toggle as a visible-break disconnect. Relative humidity rating of 95 % at 55 °C confirms it handles condensation-prone enclosures without internal tracking.
Integration into the panel — what the DIN rail and terminals mean
At 18 mm wide (2 modules), it leaves room for adjacent breakers, RCDs, or auxiliaries in the same row. The toggle and trip indicator (local signalling) are front-facing — legible in a crowded enclosure. IP20 finger protection on the front; the busbar and terminals are live when the breaker is on, so the panel cover must be fitted before energising. Double terminals accept one incoming and one outgoing conductor per pole — useful for daisy-chaining or paralleling feeds without a separate terminal block. Torque to 3.5 N.m; use a torque screwdriver to avoid terminal damage or loose connections that generate heat. Rated insulation voltage (Ui) is 500 V AC — the internal clearance and creepage distances are designed for 400 V three-phase systems (phase-to-phase) plus a safety margin. That matches the overvoltage category IV rating.
That electrical endurance is typical for a distribution MCB — not designed for frequent switching (use a contactor for that), but it will handle routine isolation and fault clearing over the life of the panel.