The circuit arrangements for each of the installations, the final circuit cable selection, the maximum demand estimation, and the circuit protection arrangements should be designed.
For each installation, the electrical design process steps are:
- Select required electrical apparatus and place in building location
- Identify circuits, main switchboard(s), submains and subboards
- Determine cable run lengths, and determine switch arrangements
- Size cables according to current rating and voltage drop
- Determine maximum demand for circuits, submains, installation
- Determine protection equipment - CB's, fuses, apparatus control
Your design process should proceed by preparing a rough layout sketch of the installation to establish the required circuits and estimate the circuit cable lengths (add 50% to your estimated lineal distance). Then create a schematic diagram for the installation, and proceed to enter in circuit details (number of points, loads, cable lengths, etc). Once the schematic is established, the detail design can proceed in terms of cable sizing, maximum demand estimation and circuit protection arrangements.
Please note that the specifications given for the installations are not particularly accurate or complete, and are provided primarily to define the electrical requirements in concept. You should estimate any obvious missing information, and add additional load requirements if they seem necessary. In any case, a building electrical installation design should always have some spare capacity and leeway, to allow for future expansion of the premises and usage. Remember, there are no "right" answers for these designs - just make sensible decisions and proceed accordingly.