80 A MCCB with high breaking capacity for line protection
The Siemens 3VA1180-5EF36-0DC0 is a SENTRON 3-pole molded case circuit breaker (MCCB) rated for 80 A continuous at 40-50 °C ambient, derating to 74 A at 70 °C. It carries a 187 kA breaking capacity at 240 V AC — that's the short-circuit current it can safely interrupt without welding contacts or rupturing the case, sized for high-fault panels near transformers or large motor banks. The 800 V rated insulation voltage means it's comfortable on 480/600 V systems as well.
Breaking capacity across voltages
Breaking capacity drops as voltage rises: 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at both 500 V and 690 V. That 17 kA floor at 690 V is still respectable for most industrial distribution, but if your fault current at 690 V exceeds that, you need a different frame. The 187 kA at 240 V is the headline number — common for panelboard mains on the secondary of a 500 kVA transformer.
Built-in undervoltage release and auxiliary switches
This variant ships with an undervoltage release (UVR) factory-fitted — it trips the breaker when supply voltage drops below a threshold, standard for motor starters or emergency-stop circuits that need a guaranteed drop-out. Also included: two HQ auxiliary switches for remote status indication (open/closed/tripped). No communication function or ground-fault monitoring on this version — it's a straight line-protection breaker.
Thermal derating and power loss
Rated current holds flat at 80 A from 40 °C up to 50 °C, then steps down: 78 A at 55 °C, 77 A at 60 °C, 75 A at 65 °C, 74 A at 70 °C. Maximum power loss at rated load is 21.7 W — that's the heat the panel must vent. Operating range is -25 °C to 70 °C, storage from -40 °C to 80 °C.