Rated for 125 A continuous — what that means for the panel
The 3VA1112-5EF32-0AA0 carries a 125 A continuous rating at 40 °C ambient, and it holds that same 125 A all the way up to 50 °C — no derating needed for a warm enclosure. Above 50 °C the curve steps down: 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, 114 A at 70 °C. That means if your panel ambient sits at 55 °C, you still get 122 A of headroom, not a forced downsizing. The TM240 overcurrent release is fixed thermal-magnetic, no electronic adjustment — set it once and it stays. No trip indicator, no undervoltage release, no ground-fault monitoring on this variant; it's a straight line-protection breaker for feeder or main applications where you don't need add-on accessories.
Interrupting capacity — 187 kA at 240 V, and the drop-off curve
This breaker's interrupting rating is not a single number — it's a voltage-dependent curve. At 240 V it clears 187 kA, which is high enough for most secondary-side transformer feeds or large bus risers. At 415 V it's still 121 kA; at 440 V it drops to 75.6 kA; at 500 V and 690 V it holds at 17 kA. If your system voltage is 480 V or 600 V class, the 17 kA at 500/690 V is the figure you coordinate against. The rated insulation voltage is 800 V, so the breaker is physically rated for the higher-voltage networks — the interrupting curve is the limit, not the insulation.
Panel fit — 3-pole, 76.2 mm wide, IP40 front
Three-pole construction, 76.2 mm wide (3 inches), 130 mm tall, 70 mm deep. The IP40 rating on the front means it's protected against tools and solid objects larger than 1 mm — standard for a panel-mounted breaker behind a closed door. No communication function, no voltage trigger, no auxiliary measurement. It's a standalone thermal-magnetic MCCB sized for a 3-pole DIN or base-mount footprint. The 28.1 W maximum power loss at full load should be factored into the enclosure thermal budget — not negligible if you're packing multiple frames in a small cabinet.