What this MCCB is and what it does
The Siemens SENTRON 3VA1110-3EF36-0AF0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection — the primary role is protecting cables and busbars from overloads and short circuits in distribution panels. It carries a continuous current rating of 100 A at 40 °C ambient, with a TM240 thermal-magnetic overcurrent release that provides fixed thermal and magnetic trip thresholds. The interrupting capacity reaches 75.6 kA at 240 V, dropping to 52.5 kA at 415 V and 32 kA at 440 V; at 500 V and 690 V it holds 11.9 kA. That spread tells you this breaker is sized for low-voltage main or feeder duty where high fault currents are possible at the lower end of the voltage range.
Thermal derating and panel fit
The 100 A rating holds flat from 40 °C through 50 °C, then begins a gentle slope: 98 A at 55 °C, 96 A at 60 °C, 94 A at 65 °C, 91 A at 70 °C. That means in a warm enclosure — say a non-ventilated panel near a process line — you lose about 9 % of the rated current at the upper operating limit. The dimensions are 130 mm tall, 76.2 mm wide, and 70 mm deep, which fits the standard SENTRON 3VA footprint; the 70 mm depth is shallow enough for most 200 mm deep enclosures without crowding the gland plate. Rated insulation voltage is 800 V, so it's comfortable on 480/277 V or 600 V systems with headroom.