The Siemens SENTRON 5SV8101-4KK is a modular residual current device (RCD) of Type B, meaning it detects AC, pulsating DC, and smooth DC fault currents — the full spectrum needed for drives, UPS systems, and PV inverters where pure AC-only RCDs can blind. Rated 230 V AC, 50/60 Hz, with an IDN of 30 mA and a frequency range from 0 to 2000 Hz, it covers both line-frequency and variable-frequency drive leakage. The LCD residual current display and error memory help a maintenance tech see what tripped and when, without needing a scope.
Snaps onto DIN rail (fastening method: DIN rail), 36 mm wide — three modular width units — and 64 mm deep. Screw-type terminals accept AWG 24 to AWG 14, with 8 mm strip length. Compatible with summation current transformers, max wire length 10 m.
Operates from -25 °C to 55 °C, with up to 95% humidity. Supply voltage range is 184–276 V AC, with a maximum power loss of 6.5 VA. Two CO auxiliary relay contacts rated 5 A / 250 V AC are built in. Password protection prevents unauthorized changes to the trip settings.