Abstract: A pilfer proofing system for electric meter boxes having a meter base box which carries a plug-in terminal block set and a meter box cover having an opening through which a plug-in meter passes to engage contact female or socket terminals in a terminal block set. A contact terminal block adaptor carrying insulating cages frictionaly retained in the female socket terminal of the contact block set springs are included in the female socket terminals to assure continuous electrical contact and avoid hot spots. The meter box has a pair of lateral meter stops which are clamped between one end of an annular, cast aluminum ring and a pair of insulated, bifurcated clamp bars positioned behind the meter stops which, in turn, are secured to a common metal bar housed in a recess in the adaptor. The illustrate clamp bars have bifurcated ends which more evenly distributes the mechanical forces to the meter box by providing a plurality of distributed contact or load distribution points instead of one.