What it is and what the ratings mean
The Siemens 3VA1040-3ED36-0HH0 is a 3-pole IEC molded-case circuit breaker from the 3VA1 series, frame size 100, with a 40 A fixed thermal-magnetic trip unit (TM210, overload Ir fixed at 40 A, short-circuit Ii fixed at 10 × In). The breaking capacity class N gives it an Icu of 25 kA at 415 V AC — that is the maximum fault current it can safely interrupt without damage, making it suitable for distribution panels where the prospective short-circuit current at the breaker's line side is known to be 25 kA or less. The thermal-magnetic trip means no electronic adjustment; overload protection is fixed at 40 A and short-circuit pickup at 400 A (10 × 40 A). The breaker includes a shunt trip (STL) rated for 12–30 V DC and 24 V AC at 50/60 Hz, plus two auxiliary switches (HQ) and one trip alarm switch (HQ). The shunt trip allows remote tripping from a safety circuit or emergency-stop chain. The auxiliary contacts signal the breaker's open/closed state to a PLC or status lamp; the alarm switch changes state only when the breaker trips on fault, not on manual opening — useful for a remote fault annunciation.
Integration and deployment
Mounts on a DIN rail or panel-mount via the 3VA1 frame's integral latching mechanism — snaps onto a standard 35 mm DIN rail without tools. Clamp-type line and load terminals accept copper conductors up to the frame's rated cross-section (typically 35 mm² for this frame). The shunt trip and auxiliary switches are factory-installed; no field-assembly of internal accessories is required. The breaker occupies three modular width units (3 × 18 mm) on the DIN rail.