What it is and what it does
The Siemens 3VA1080-4ED36-0BA0 is a SENTRON molded case circuit breaker (MCCB) sized for line protection in distribution panels. It's a 3-pole unit rated 80 A at 40 °C with a TM210 thermal-magnetic overcurrent release — that's a fixed thermal element and a magnetic trip that handles short-circuit and overload protection in one device. The built-in undervoltage release (UVR) lets you drop the breaker remotely when control voltage falls below a set threshold, which is standard for emergency-stop or interlock circuits. Breaking capacity is the headline here: 121 kA at 240 V AC, 75.6 kA at 415 V AC, and still 11.9 kA at 690 V AC. That's high-interrupting capability for a 3-pole frame this size — it's meant for installations where fault current is substantial, like a main breaker in an industrial sub-distribution board or a feeder protecting a high-capacity busway.
Ratings and what they mean for fit
The 80 A rating holds from 40 °C through 50 °C ambient — no derating needed in a typical ventilated panel. At 55 °C it's 78 A, at 60 °C it's 77 A, and at 70 °C it's 74 A. If your panel runs hot, you still have headroom; you don't need to oversize the frame for a warm enclosure. Insulation voltage is rated at 800 V, so the breaker is comfortable on 690 V systems. Power loss maxes at 21.7 W — that's the heat it dumps into the enclosure, relevant for thermal calculations in a sealed or high-density panel. Dimensions: 130 mm high, 76.2 mm wide, 70 mm deep. That's a standard 3-pole MCCB footprint — it fits existing SENTRON 3VA mounting rails and busbar systems without adapters.