80 A MCCB with TM120M release — thermal derating and breaking capacity across the voltage range
The Siemens SENTRON 3VM1180-5MH32-0AA0 is a 3-pole molded case circuit breaker rated 80 A at 40 °C, fitted with a TM120M thermal-magnetic overcurrent release. Per the datasheet, the breaker holds its full 80 A rating from 40 °C through 50 °C, then derates linearly to 74 A at 70 °C — a curve that matters when the breaker shares an enclosure with other heat sources. Breaking capacity is 187 kA at 240 V AC, 121 kA at 415 V, 76 kA at 440 V, and 17 kA at 500 V; these are the values for coordination studies, not the continuous load. The rated operational voltage is 690 V AC and 500 V DC, with an insulation voltage of 800 V. IP40 on the front means the breaker face is protected against solid objects over 1 mm but not against moisture — standard for a panel-mounted device.
Thermal derating — what the 40–70 °C curve means for panel placement
The 3VM1180-5MH32-0AA0 carries a published thermal derating table: 80 A continuous from 40 °C to 50 °C, 78 A at 55 °C, 77 A at 60 °C, 75 A at 65 °C, and 74 A at 70 °C. That 6 A drop between 50 °C and 70 °C is the margin you lose if this breaker sits above a VFD or in a tightly packed panel. The TM120M release is a fixed thermal-magnetic design — no interchangeable trip unit, so the derating curve is the only guide for ambient-adjusted loading. Maximum power loss is 14 W.
Breaking capacity — selectivity headroom at common fault levels
At 240 V the breaker interrupts 187 kA; at 415 V it handles 121 kA; at 440 V it drops to 76 kA; at 500 V it is 17 kA. These are the short-circuit current ratings (Icu) for the respective voltages. For a 480 V panel the relevant figure is the 440 V value (76 kA) or the 500 V value (17 kA) depending on the actual system voltage — the datasheet does not list a 480 V entry, so coordination studies should use the nearest bounding value. The 187 kA at 240 V is unusually high for a 80 A frame; this breaker is sized for high-fault installations where the available fault current exceeds typical MCCB ratings.
Lifecycle and sourcing posture
The lifecycle stage for the 3VM1180-5MH32-0AA0 is listed as current — the manufacturer has not flagged this order code for phase-out or end-of-life. It is sourced and quoted to order against an RFQ through independent distribution; availability and current pricing are confirmed at quote time. No official successor order code has been published for this MPN.