Abstract: A safety construction of receptacle plugs mainly comprises a housing and an insertion piece; the housing having an inspection port provided on its top, and a cover plate that can be placed into the housing from the rear side of the housing and slides in and out to close the inspection port; the insertion piece having a plurality of troughs arranged thereon that can accommodate two sets of copper conductor plates and two fuses, each set of copper conductor plates including two separated parts connected to each other by way of a fuse that constitutes a safety device. Under the cover plate there is an overhanging separator formed to keep fuses apart to obtain a safety effect.