Class R fuse blocks connection terminal type screw, pressure plate, box and stud connectors fit a wide range of stranded or solid copper or aluminium conductors. Insulators are molded glass-filled polycarbonate (GFPC) with verified dielectric strength in excess of 2500 V. 30 A, 60 A and 100 A SJ fuse blocks feature a unique adder block configuration which can be snapped onto 1, 2 or 3-pole blocks to form multi-pole segmented blocks of as many poles as desired. All fuse clips are made of high conductivity tin-plated copper with spring reinforced clips. 4-14 AWG aluminium/copper wire range. Box type connector. Class R blocks used with A2D-R, A2K-R, TR-R.