What this MCCB is and where it fits
The Siemens 3VA2140-6HM36-0AA0 is a SENTRON 3VA2 series molded case circuit breaker (MCCB) rated for line protection in distribution panels and industrial switchboards. It carries a continuous current Iu of 40 A across the full ambient range from -25 °C to 70 °C — no derating needed up to that ceiling. The 3-pole design with an ETU330 electronic trip unit gives you adjustable overload and short-circuit protection curves, which is what you want when coordinating downstream feeders or motor branch circuits.
Breaking capacity — the number that decides selectivity
This MCCB delivers 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 3.7 kA at 690 V. Those are the maximum fault currents it can safely interrupt at each voltage level. For a 400 V panel, 187 kA gives you headroom to coordinate with a downstream 25 kA or 36 kA MCCB without the main tripping on a feeder fault — selectivity stays intact. The 800 V rated insulation voltage (Ui) confirms the internal clearances handle the higher potential without tracking.
Trip unit and protection features
The ETU330 electronic trip unit supports adjustable long-time pickup, short-time pickup, and instantaneous settings. It also includes ground-fault monitoring via summation current formation on the L-conductor — meaning it sums the phase currents to detect leakage to earth, which is useful on IT or TN-S systems where you want early warning before a bolted fault develops. The front face carries an IP40 rating, so it's protected against tools and wires during panel work but not against water ingress. No trip indicator, undervoltage release, or communication module is built in; those are external accessories if needed. The optional motor drive (product extension) allows remote charging for applications like generator paralleling or automatic transfer schemes.
What the ratings mean for your panel
The 40 A rating at 70 °C means this breaker doesn't force you to oversize the bus for a hot switchroom — it holds full rating up to that ambient. The 242 kA at 240 V is the interrupting capacity; if your available fault current at the service entrance is 200 kA, this breaker clears it without upstream fuses needing to operate. The 3.7 kA at 690 V is the low end — if you're on a 690 V industrial system, verify your fault current doesn't exceed that figure. The IP40 front protection is standard for enclosed panels; if the breaker is mounted in a washdown area, the enclosure itself handles the IP rating, not the breaker face.