The Siemens 5SV8101-6KK is a SENTRON modular residual current device (RCD) with a digital, type A design. The unit is rated for a 230 V AC operating voltage (range 184 V to 276 V) and can be set to trip anywhere from 0.03 A to 3 A residual current, with an adjustable time delay from 0.02 s to 10 s. That wide trip-current range and the selectable delay make it useful for selective coordination in distribution boards where you need the downstream RCD to clear before the upstream one.
Depth is 68 mm, height 85 mm, so it fits the usual 18 mm pitch enclosure without sticking out past the front cover. Screw-type terminals accept AWG 26 to AWG 14 supply conductors; strip length is 10 mm. The front face carries IP41 protection (splash-proof, tool-resistant), while the connection terminals are IP20 (finger-safe). That split rating is common for panel-mount RCDs — the front can take a light splash during cleaning, but the wiring compartment stays protected inside the enclosure.
Auxiliary contacts and external CT support
This RCD includes two CO (changeover) auxiliary contacts rated at 6 A / 230 V AC, which can be wired for remote tripping indication or status feedback to a PLC. It also supports an external summation current transformer (CT) — compatible types are the 5SV8702-0KK through 5SV8706-0KK series — with a maximum wire length of 10 m between the CT and the device. That external CT capability means the 5SV8101-6KK can monitor circuits where the conductors don't all pass through the internal sensor, such as in retrofit or distributed-load situations.