A retainer apparatus includes a post having a first end to be received by an opening of a wall plate cover of an outlet and a second end opposite the first end. At least a portion of the post has a plurality of grooves positioned between the first end and the second end. The plurality of grooves forming a retainer-receiving portion. A plug retainer is moveably coupled to the post. The plug retainer to slide along the retainer-receiving portion in a linear direction relative to the grooves when the plug retainer is moved relative to the retainer-receiving portion of the post.