Abstract: A clamp for battery jumper cables includes a pair of pivoted terminal gripping members with a switch and linkage arrangement connected between a conductive jaw and the conductive jumper cable to facilitate electrical connection and disconnection of the jaw and jumper cable in a controlled, spark-free manner. The linkage includes first and second lever sections pivotally connected to one of the handle sections of the terminal clamp. A first lever is operated as the clamp is grasped in the user's hand. This lever causes the over-center linkage to shift to a first over-center position, opening the switch and breaking electrical contact between the clamp and jumper cable before the jaws are forcibly opened. The over-center linkage serves to hold the switch in an open, nonconductive state even though the clamp handles are released to secure the jaws against the terminal.