My theory for the fork in the electrical socket is that when Cooper originally appeared in the world via an electrical socket, the 'download' wasn't complete for some reason, resulting in Dougie Jones.

The Gordon Cole reference on the tv woke him up enough, just enough, to get him to the socket to complete the download and recover that part of himself that was still stuck in transmission.

So it's not so much that he just shocked himself awake, rather the electrical discharge allowed for the remaining part of his personality and faculties to download and reintegrate with him.