It provides selective protection for all DC 24 V load circuits at a width of only 12.5 mm. This is achieved by a combination of active electronic current limitation in the event of a short circuit and overload disconnection at typically 1.25 times rated current. Plugged into an E-T-A socket, which is available with screw terminals or screwless terminals, the REF16-S provides ease of installation. The sockets allow power distribution and signalling via plug-in type jumpers. In addition the REF16-S latches on when plugged into the socket and by means of coding pins a clear assignment to current ratings or slots is possible. Dimensions are in compliance with the standard DIN 43880 for the installation of built-in units.