What this MCCB is and what it does
The Siemens 3VA1140-5EF32-0CC0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection — meaning its primary job is guarding cables and busbars against overload and short-circuit, not switching motor loads on and off. It's a 3-pole unit rated 40 A continuous at 40 °C, and it carries an undervoltage release (UVR) so it can be tripped remotely if control voltage drops, plus two factory-fitted HQ auxiliary switches for status feedback to a PLC or indicator lamp.
Short-circuit ratings that matter for coordination
The interrupting capacity tells you where this breaker can sit in a distribution panel without needing a current-limiting upstream device. At 240 V it's rated 187 kA — that's a very high figure, typical for a main or large feeder breaker. At 415 V it's 121 kA, at 440 V it's 75.6 kA, and at 500 V and 690 V it drops to 17 kA. If your system voltage is 480 V or 600 V class, the 17 kA SCCR still covers most industrial service-entrance and sub-feed applications, but you'll want to verify coordination with the upstream transformer or generator breaker.
Thermal derating — don't ignore the fine print
This breaker holds its full 40 A rating up to 50 °C ambient. At 55 °C it derates to 39 A, at 65 °C to 38 A, and at 70 °C to 37 A. If your panel runs hot — say, a sealed enclosure next to a furnace line — you need to account for that derating. The rated insulation voltage is 800 V, so it's comfortable on 480 V and 600 V systems with margin.
Built-in auxiliaries and release
The 3VA1140-5EF32-0CC0 comes with an undervoltage release (UVR) as standard — that's the '0CC0' suffix code. It also has two HQ auxiliary switches, which are the high-quantity (2 x changeover) contacts for remote indication. No ground-fault monitoring is included, so if you need GF protection you'll need an external module or a different variant. The basic switch version is 3VA11405EF320AA0, meaning the trip unit is fixed thermal-magnetic, not electronic.
Physical fit and panel integration
Dimensions are 130 mm high, 76.2 mm wide, and 70 mm deep. That's a 3-inch wide footprint — standard for a 3-pole MCCB in this current class. It mounts on a DIN rail or directly to a backplate via the screw terminals. The 70 mm depth means it fits in shallow enclosures where a deeper breaker might hit the door or gland plate. Power loss is 13.3 W maximum, so heat dissipation inside a sealed cabinet is manageable but not trivial if you have several breakers ganged together.