Idea for a project

[sparkz_alot]

Welcome, Rafael.  You did not mention your familiarity with Python. Are you new to the language, somewhat knowledgeable, or quite the expert?  The reason I ask, is the project you describe could and most likely would become quite daunting.  For instance, here in the U.S. the electrical requirements are different for residential than for commercial, which are different than industrial.  Conductor sizing is dependent on the material used (for example: copper or aluminum). Just taking copper, for instance, it is usually 'mixed' with another metal.  So pure copper will have a different ampacity than a blend. Don't forget, building codes will also play a big role.  There are charts available online that list all the values and conditions which Python has modules you can use to grab this information and save it to a file for you.  Python also has modules (whether built-in or third party) that allow you to work with Excel or actual databases.

Do you want to present your information as a web interface, a GUI application or a simple command line?  Again, Python has the tools you need to accomplish this.

My advise would be to pick the easiest part of your project and start with that. Even if it's a simple 'menu' driven script, for example:

1. Ask user for the number of light bulbs
   
2. Ask user for the wattage of the bulbs
   
3. Return the 'safest' minimum conductor size and material possibly even the cost.
   

This would lead to the proper sizing of the breaker for this particular circuit, and so on.

In the end, you should be able to fit all the 'little' pieces into one big project.

Finally, if you run into problems along the way, that's what we are here for 

Good luck!