An adapter for a clamping device for the electrical connection of a cable or line is disclosed. The clamping device includes an electrical contact point and a height-adjustable clamping plate, and the clamping plate is designed to press the cable or line mechanically against the electrical contact point of the clamping device. In at least one embodiment, the adapter is designed to be able to be fastened to the clamping plate of the clamping device, so that using the adapter it is possible to carry out an adaptation to the cross-section of the cable or line to be clamped, to carry out an adaptation to the elevation of the height-adjustable clamping plate of the clamping device or to adjust the width of the clamping plate.