Type B+ residual current detection covers smooth DC, pulsating DC, and high-frequency AC fault currents — meaning it handles the leakage profiles from VFDs, UPS systems, and EV chargers that a standard AC or A type would miss. The 125 A rating applies at 30 °C; derate to 115.62 A at 40 °C, 111.25 A at 45 °C, 106.25 A at 50 °C, 101.25 A at 55 °C, and 96.25 A at 60 °C — the thermal curve governs real-world loading in a warm enclosure.
Occupies 11 modular width units (MWU) on a DIN rail; the housing is 198 mm wide, 90 mm high, and 77 mm deep, with an installation depth of 70 mm behind the panel face. Mounting position is unrestricted, and the supply cord can enter from either the top or bottom — useful when retrofitting into an existing board with fixed busbar routing.