What the 30 kA breaking capacity means for your panel
The G12F4F100 is a 4-pole GoPact MCCB 125 molded-case circuit breaker with a TM-D thermal-magnetic trip unit rated 100 A at 40 °C. Its headline rating is 30 kA breaking capacity at 380/415 V AC (performance level F), which means it can safely interrupt a fault current up to 30,000 A without welding contacts or rupturing the case — critical for panels with high available fault current from a transformer or generator feed. That 30 kA figure is the Icu (ultimate short-circuit breaking capacity) per EN/IEC 60947-2. For distribution duty (utilisation category A), the breaker is not intended for motor starting — it's a line feeder or sub-feed protector where the fault loop impedance is low enough to deliver that kind of fault energy.
Trip unit and protection coordination
The neutral protection setting is 1 x Ir (4D), meaning the neutral pole tracks the phase protection at the same Ir setting — no reduced neutral rating. This matters for 4-wire systems where neutral current can equal phase current, such as in IT or TN-S networks with non-linear loads. Power dissipation per pole is 18.7 W, so total heat load for the 4-pole breaker at full rated current is about 75 W. In a crowded panel, that heat needs to be vented or accounted for in the thermal budget — particularly if the breaker is mounted horizontally (which is allowed, per the mounting position spec).
Physical fit and installation
Dimensions are 130 mm high × 100 mm wide × 60 mm deep, with a 25 mm connection pitch. IP20 finger-safe terminals mean the live parts are protected against accidental contact with a finger (per IEC 60529), but the breaker is not water- or dust-sealed — it's for indoor panel installation only.
It is suitable for isolation per the standard, so it can be used as a disconnecting means where local codes accept IEC 60947-2 devices. The grey (RAL 7035) enclosure is the standard industrial colour.