Hello not bad .... however I will make some questions ... Each of the sectional boards contains a main thermal and a differential. Since both devices exist on the main board, it only requires one of these devices as a header switch on each sectional board, not both, choose which one should be and the other discard The upstairs air conditioner has a 4 mm2 cable and 20 thermal cable, unless it is a large capacity equipment, it is an excess the 6 mm2 sectional circuit is branching into two branches, said connection must be made through suitable terminals or connections, conventional splices are not allowed I show you two options, the first one is using the same sectional for both boards with a terminal board where it is ratified, although this option is not clear since a sectional circuit must feed a board The best option would be the following option 2 in this option you will use 2 sectional circuits, both 6 mm2 to avoid having to place lower value thermals on the main board , since they are only 11 m, its assembly is not so problematic In both cases the thermal of the plant air conditioning will be 10A and the circuit armed with conductors 2.50 mm2. The distributions between thermal would be with connection combs due to the number of circuits avoid placing 2 differentials in series, in the second option I place both differentials on the main board if it is required in these sections differential protection, otherwise you can exchange its location with the header thermal of each sectional board any questions comment