Can I add a 100 amp subpanel to a 200 amp main panel in a house and how

Yes you can. I have asked to have this moved to Electrical where tkrussel will give you a good explanation of how. Might let him know how close it will be to the main panel.

Will you be able to answer Labman's question?



Might let him know how close it will be to the main panel.

Can you tell me how much knowledge you have of wiring?

Here is an example of a 200 amp main panel on the left and 100 amp sub panel on the right. Picture attached

Good Luck!