The electronics are designed to fit in a standard 5/8" PVC conduit. The sensor completely submerges in a 5/8" PVC Conduit, the electronics even fits in a 16mm flexible conduit. So it is easy to mount the sensor in a ceiling or wall because only a small hole is required, ca 11mm.

The smart mini motion sensor is "2-wire" connected to a 24V input type EN61132-2. Only two wires are required to power the sensor and also get the values off all measured environmental units. One wire connects 24V to the sensor, the other wire is the signal wire and is connected to the input of the controller as shown in the diagram.