What it is and what it does
The Siemens 3VA1080-4ED42-0AA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection — it sits at the feeder or subfeed in a distribution panel, not on a motor branch. Four poles, rated 80 A continuous at 40 °C, with a TM210 thermal-magnetic overcurrent release (the '210' means the thermal pickup is fixed at 80 A, magnetic trip at 10× In). Breaking capacity runs 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 500 V and 690 V — so it handles high-fault utility feeds in North American 240/480 V systems and European 400/415 V networks without cascading upstream.
Thermal derating — the real-world current
The 80 A rating holds all the way to 50 °C ambient — no derating needed in a typical ventilated panel. At 55 °C it drops to 78 A, at 60 °C to 77 A, at 65 °C to 75 A, and at 70 °C to 74 A. If the panel runs hot (sun-loaded roof install, adjacent drives), factor the actual ambient against this curve rather than oversizing the frame.
Panel fit and integration
The breaker measures 130 mm high, 101.6 mm wide, 70 mm deep — a 4-pole MCCB in a compact frame that fits standard distribution panelboards. IP40 on the front (finger-safe), no communication module, no undervoltage release, no ground-fault monitoring. It's a straight line-protection device: wire it in, set the torque on the terminals, and it protects the cable downstream.