Remove the power supply cord from the jack hammer.

As you remove the cord, note the position of the cord guard. During reassembly, make sure the collar of the cord guard fits back into its slot in the handle.

When reinserting the two exposed wire ends into the green terminal:

First, compress the wire ends so they are relatively flat.

Then, insert each wire end into the green terminal, noting the polarity of the cables: the black cable should go into the upper slot, and the white cable should go into the lower slot (as shown in the third photo of this step).

Finally, gently tighten the screws until the wires are secured.