You might want to check out the Eletrigon object, found here
http://www.archicad.ca/
, for the electrical plan.
However, for the diagraming that you want to do you will either need to make some 2D objects for the various devices and switches or just make do with lines, arcs, fills, etc since ArchiCAD is not set up for this type of work out of the box.
If you draw your symbols in the floor plan you can then save them as simple 2D objects (see your Reference Manual found under the Help menu). While objects made that way are not intelligent and only have the pen/fill/material/etc. of the initial drawing you used to make the object. However, if you know some basic GDL (the object language used by ArchiCAD) then you can either code the objects from scratch or at least adjust the simple ones you make from the floor plan to give them some simple intelligence.
Erich
AC 19 6006 & AC 20
Mac OS 10.11.5
15" Retina MacBook Pro 2.6
27" iMac Retina 5K