Consider an RCBO "upright" in a domestic CU. Its base would be be connected to a bus bar and with the load terminals at the top.. Rotate the bus bar and the RCBO 90 degrees clockwise and you get what's in the photo.
Consider an RCBO "upright" in a domestic CU. Its base would be be connected to a bus bar and with the load terminals at the top.. Rotate the bus bar and the RCBO 90 degrees clockwise and you get what's in the photo.