Apparatus for electrical installation

Installation system for controlling an electrical building installation has a programmable computer unit for switching electrical loads (70-73). The computer unit has a number of function groups (I1-I4, ZE, ZA, AW) for controlling standard and central functions and which have one or more inputs from the computer unit. Individual function groups have one or more computer outputs (C1-C4) for controlling the loads and the computer unit assigns central functions (ZE, ZA, AW) to the outputs as well as manual operating keys.