What the ratings mean for fit
The Siemens SENTRON 3VA1112-4ED36-0AC0 is a 3-pole molded case circuit breaker (MCCB) rated 125 A continuous at 40 °C, with the TM210 thermal-magnetic overcurrent release. That 125 A holds steady through 50 °C; above that it derates to 122 A at 55 °C and 114 A at 70 °C — so in a warm panel you lose about 9% of the headroom by the top of the operating range. The interrupting capacity is the real selector: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. If your fault current at the board is above 75 kA at 415 V, this breaker handles it without cascading upstream — that's the decision point for a high-capacity distribution panel.
Panel integration and footprint
At 70 mm deep, 76.2 mm wide, and 130 mm tall, this MCCB fits standard SENTRON mounting patterns — the 3-pole width matches the 76.2 mm (3-inch) module pitch common in Siemens switchboards. The 800 V rated insulation voltage (Ui) means it's rated for 690 V line-to-line systems without additional series isolation. Power loss is 28.1 W maximum at rated load, so factor that into enclosure thermal calculations if the panel is densely packed.
Auxiliary switch and accessories
Factory-fitted with 2 auxiliary switches (HQ design) — no separate add-on required for basic status feedback. No undervoltage release, no ground-fault monitoring, no trip indicator, and no communication function on this variant. The base switch part is 3VA11124ED360AA0, so if you need a bare breaker without auxiliaries, that's the order code to cross-check.