What this MCCB is and where it fits
The Siemens 3VA1150-3EF36-0AB0 is a 3-pole SENTRON molded case circuit breaker rated for 50 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release. It is a line-protection version — meaning it is intended for feeder and distribution duty rather than motor branch-circuit protection — and carries two built-in auxiliary switches (HP type) for status feedback to a PLC or panel indicator. The 76.2 mm width (roughly 3 inches) and 130 mm height let it drop into a standard panel footprint without surprises; the 70 mm depth keeps it clear of gland plates in shallow enclosures. IP40 on the front means it is protected against tools and small wires but not washdown — keep it inside a closed cabinet.
Breaking capacity — what the numbers mean for coordination
This breaker delivers 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 10.5 kA at 690 V. Those are the maximum fault currents it can safely interrupt at each voltage level without welding contacts or rupturing the case. For a 480 V panel (common in North American industrial distribution), the 415 V figure is the closest reference — 52.5 kA gives substantial headroom above a typical 25 kA or 42 kA available fault current. At 690 V the 10.5 kA rating still covers most European industrial grids.
Thermal derating — don't size by the nameplate alone
Rated continuous current holds at 50 A from 40 °C through 50 °C ambient. Above that it steps down: 48 A at 55 °C, 47 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. If the breaker lives in a crowded panel or near heat-generating gear, use the 55 °C or 60 °C row for sizing — the 50 A nameplate is only valid up to 50 °C.