The 800 V rated insulation voltage gives headroom for 690 V systems, though the 3.7 kA breaking capacity at 690 V is the limiting factor at that voltage class.
Breaking capacity across voltages — where it fits
Breaking capacity drops sharply above 500 V: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 3.7 kA at 690 V. That 690 V figure is low enough that for 690 V applications you'd typically step up to a higher-rated frame.
The 3VA2125-5HM36-0AA0 measures 86 mm deep, 105 mm wide, and 181 mm high — a standard 3-pole MCCB footprint that fits most DIN-rail or panel-mount enclosures.