This will not make me very popular but it is the truth. Without a license, not very much. At The present time most states allow you to do whatever you want in your own home. But doing electrical work yourself is a gamble. How much are you willing to risk to save money. There is a reason why it takes so much training to become an electrician. Do not make a mistake by taking electricity lightly, even the smallest job could be a safety hazard. Why take a chance. Get a professional to do this work.
Also In some states the homeowner can pull his own Electrical permit for work in his single family home, what he does not know is that in case of damage or fire caused by his work, his homeowners insurance will not pay, they will only if the work is done by a licensed Electrical Contractor. You should check with your homeowners Insurance Co., and they should sign a document or something to this effect to acknowledge this when they pull a permit.
The most dangerous time is when you tell yourself. This is easy. I can do it myself. Why should i get an electrician? Than when you don’t remember where all those wires went, or your hair is standing straight up, you say to yourself. Well maybe we better call someone to straighten up this mess. Now it will cost you double what you thought you were going to save in the beginning.
It is a violation for a licensed electrician or systems technician to connect wiring from components that have been wired by an unlicensed person. Doing electrical work without a permit is illegal in most areas. It could also invalidate your homeowner’s insurance.
To get answers to more questions about your electrical system see: Master Electric FAQs