What this MCCB does on the line side
The Siemens SENTRON 3VA1163-5EF36-0HH0 is a 3-pole molded case circuit breaker rated for 63 A continuous current at 40 °C, with a TM240 thermal-magnetic overcurrent release. It holds 187 kA interrupting capacity at 240 V and 121 kA at 415 V — enough to handle high-fault utility feeds or transformer secondaries without cascading upstream. The shunt trip (STL) allows remote tripping from a safety relay or E-stop string, and the integrated 2 aux + 1 alarm switch (HQ) gives the PLC a positive status signal on open/close and trip. No undervoltage release, no phase-failure detection, no communication module — this is a straight-ahead line-protection breaker for distribution panels where you need raw interrupting muscle and a clean aux contact set.
Thermal derating — what 63 A actually means at panel ambient
The 63 A rating holds flat from 40 °C to 50 °C, then drops to 60.48 A at 55 °C, 59.22 A at 60 °C, 57.96 A at 65 °C, and 56.7 A at 70 °C. If your panel ambient runs 55 °C — common in a sealed NEMA 12 enclosure with a transformer nearby — you lose about 2.5 A. At 70 °C, you're down to 56.7 A, a 10 % reduction. The breaker itself operates from -25 °C to 70 °C ambient and stores from -40 °C to 80 °C, so the thermal curve is the only limit. Mount it with 70 mm depth clearance on the DIN rail; the 76.2 mm width (roughly 3 inches) fits standard 3-pole MCCB panel cutouts. IP40 on the front means it's splash-protected from the panel door side but not sealed for washdown.