The digital FI-protection switch Type B are suitable for all systems, machines and equipment in which DC fault currents can occur, e.g.:Dc applications such as photovoltaic or uninterruptible units- Medical devices such as x-ray devicesTest and experimental facilities in laboratory and training roomsFrequency converters for motor applicationsControls for lifts and cranesDrives with speed control for rolling machines, rotary benches, mills,â¦Workshops (for example, for the use of welding devices)- ConstructionCharging stations for electric cars.Type B: detects along with fault currents in alternating current and pulse current range also DC fault currents in the frequency converter controls, photovoltaic systems as well as in the use of various electronic devices in the budgetary area can occur, and thus increases the safety.This text is machine translated.