What this 3VA1112-6EF36-0AG0 is and what it does
The Siemens 3VA1112-6EF36-0AG0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection — it's the main disconnect and fault interrupter for a feeder or large branch circuit in a distribution panel. Rated 125 A continuous at ambient temperatures up to 50 °C, it carries that full current without derating; above 50 °C it steps down to 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. The TM240 thermal-magnetic release gives it a fixed thermal pickup and magnetic trip characteristic suited to protecting cable and bus, not motor overloads — this is a distribution breaker, not a motor-circuit protector. Breaking capacity is 220 kA at 240 V, 154 kA at 415 V, 75.6 kA at 440 V, and 17 kA at both 500 V and 690 V — high enough for most industrial service-entrance and sub-distribution applications where fault current is substantial. Rated insulation voltage is 800 V, so it's rated for 690 V systems with margin. It's a 3-pole unit with a built-in auxiliary switch and a separate trip alarm switch (HP type), which gives you one set of contacts for status feedback and one for fault annunciation — that's another SKU I don't need to add for remote indication.
Mounting and panel fit
The 3VA1112-6EF36-0AG0 measures 70 mm deep, 76.2 mm wide, and 130 mm tall — it snaps onto DIN rail in a standard distribution panel, and the 76.2 mm width (3 inches) is the standard 3-pole MCCB footprint. Max power loss is 28.1 W, so factor that into enclosure thermal calculations if you're packing several breakers in a sealed box. Operating temperature range is -25 °C to 70 °C; storage from -40 °C to 80 °C.