Because of a faulty delivery, I had two of these RCDs in various versions (2- and 4-pole) in his hands. In both there was the symbol of the switch type "AC" means responds only to AC fault currents that switch. In Germany, this type is not allowed according to VDE (perhaps the switch is so cheap?). This requires at least the type A (the addition responds to pulsating DC residual currents) or Type B (all kinds of DC residual currents).
The installation of the "AC" type in private households is dangerous due to lack of protective effect.
The switches were therefore untested back to the dealer. This told me later, now of the type "A" switch had arrived.
So be sure to pay attention to the correct type before installing this switch.
