Abstract: Each of a pair of electronic semi-conductor switching devices is disposed between a corresponding pair of conductor plates. The semi-conductor devices are aligned with each other, and the complete assemblage is held together by means of a clamp which applies a clamping force to tightly hold each semi-conductor device between its corresponding pair of conductor plates. A spacer arrangement separates the two pairs of plates and includes a spherical pivot bearing seated between a pair of individual spacer plates which are in turn separated from the immediately adjacent conductor plates by means of annual insulating spacers. The pivot bearing permits limited pivotal movement of one pair of plates relative to the other so that excellent surface contact between each semi-conductor device and its corresponding pair of conductor plates is maintained when one plate of each pair is attached to a corresponding electrical terminal fixedly mounted on a control panel into which the assemblage mounts.