A surgical instrument, such as an electrical ablation device, including a first elongate body having an insert and a second elongate body having an electrically insulative sheath that defines a bore. A mating element mates the elongate bodies when at least a portion of the insert is received within the bore. The second elongate body is configured to receive electrical energy from the first elongate body and transmit the electrical energy to an electrode. In certain embodiments, the electrical ablation device may include first and second elongate bodies. The first includes an electrically conductive insert configured to electrically couple to an energy source and apply the electrical energy to tissue, and the second includes an electrically insulative sheath defining a bore configured to receive the insert therethrough and move proximally or distally relative to the insert.