Can an Electrical Engineer also study Accounting and Finance to work as an Accountant too to make extra money per year?Or you must gain?

Seriously? You can learn 100 professions if you want.

It depends on your goals. Some people take up accounting as a second career, but you need to decide which is your primary one. Accounting can be a difficult field to break into and tax season entails long hours.

If you're unsure and just looking for a second income, consider doing tax prep. It's a great way to get experience.

The most successful lawyers I worked with originally trained as engineers. The mental discipline of engineering was good training for law ... and they made a LOAD more money as lawyers. I am sure an engineer COULD train in accounting and finance and make a success of it but it would not be easy to try to run two careers side-by-side.  Once you get involved in management and accounting and law, the hours get very unpredictable and you have to be willing to suspend all other activities if the business needs you.