The 125 A rating holds flat from 40 °C up to 50 °C ambient; above that it derates to 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C, so in a warm enclosure you need to account for the reduced capacity rather than rely on the nominal number. Interrupting capacity is the headline differentiator here: 187 kA at 240 VAC, 121 kA at 415 VAC, 75.6 kA at 440 VAC, and 17 kA at both 500 VAC and 690 VAC. Those figures mean this breaker can be applied on high-fault panels where a standard 25 kA or 36 kA MCCB would fail to clear a bolted fault — think large transformer secondaries, busway feeds, or main disconnects in industrial switchboards. Dimensions are 101.6 mm wide (4 in), 130 mm high (5.12 in), 70 mm deep (2.76 in) — a 4-pole frame that fits standard SENTRON mounting patterns.
Integration and deployment context
The 4-pole configuration handles three-phase plus neutral switching, common for main or feeder breakers in 400 VAC distribution.