An electric socket includes a socket housing defining prong slots therein. Conductive terminals are disposed in the socket housing. An electrically and thermally insulating protective plate is disposed in the socket housing. The protective plate is disposed between the conductive terminals and the side of the socket housing that forms the prong slots. The protective plate includes a substrate and ring protrusions extending into the prong slots and each having an outer profile matching an inner profile of a corresponding prong slot. A central portion of each ring protrusion defines a through hole aligning with a corresponding prong slot. By providing the electrically and thermally insulating protective plate between the conductive terminals and the socket housing, the electric socket can prevent the high temperature and sparks produced at the conductive terminals from igniting the socket housing to cause fire, thus having improved product reliability.