It is important to understand the nature of a co-op situation. You actually do not own your apartment. You own shares in the entire building with rights to occupy your apartment. In essence, everyone owns the walls in your apartment and ergo have rights to decide what goes in those walls. Also they have the right to determine/approve any plans you have to remodel. As to the electrical work you want done, whether you agree or not, you have also legally contracted with this electrical company via your Co-op board. And when that Co-Op board decides to make a major infrastructure improvement like replacing the windows in your apartment, they have the rights to do that and charge you a surcharge in your maintenance fee regardless of your ability to pay. You can also be held financially liable for any law suits against your Co-op. Such as a trip and fall on the sidewalk outside.
I am surprised that your real estate agent did not at some point explain this to you. And if you have already purchased, somewhere you were handed a copy of the propectus on the Co-op which should include all the information you require on your co-op board.
Co-Ops can be less expensive to purchase, but once you add in the potential for liabilities, the fact that your neighbors have decision making power in your apartment, and the ever skyrocketing maintenance fees, in the long run they are probably not a good financial plan.