Dealing with electricity is a difficult, complicated task. In comparison to other things, you can DIY, dealing with electrical systems can be quite dangerous and might even lead to death if you are not careful.
Of course, there are citizens that, although don’t have a license or studies to properly deal with electrical systems, ’ve managed to build enough experience and training to come by with some simple solutions. My father is a great example of this. Back when I was a kid he used to play around a lot, and self-taught himself how to deal with certain things.
From repairing electronic devices to fully installing or repairing some parts of the house’s electrical system, he was very capable, but he had years of experience and training, and it was possible only because he was a tough guy, and quite curious.
Most people, though, know anything about electricity, and doing stuff like installing, repairing, and maintaining an electrical system, can prove to be an incredible challenge. On those occasions, it would definitely be wise to hire a professional.