There is no electrical activity, nothing works?

My car recently had no power after running fine before being shut off. I had the battery replaced two days ago and this is the first time it has happened. I removed the negative cable to inspect it because it is bared near the metal partition and thought it was a short. After replacing it, it started and the electrical worked. Later in the evening it happened again, I wiggled the negative wire and lifted it off the bare part of the wire and it started. When there is no electrical activity, nothing works. No lights, music, or engine turning over. Any thoughts? The service engine soon light does not come on.