A clamp for electrically connecting a contact rail and a bus bar of a PV assembly includes a base having a first end and a second end positioned opposite the first end. Two fixing portions extend from both sides of the base and away from and perpendicular to the first surface, and adapted to detachably fix the clamp to the contact rail. An extending portion has a first bending extension extending and bent from the base, a parallel extension connected with the first bending extension and extending in parallel with and apart from the first surface, a second bending extension connected with the parallel extension and extending between the two fixing portions, and an actuating extension connected with the second bending extension and extending beyond the base. A locating protrusion is formed integrally with the base and adapted to engage within the first locating element and the second locating element.