Rubber Electrical Tape. Pads, Helps Protect and Insulate up to 69kV.

You should use a minimum of two half-lapped layers of vinyl tape to insulate and jacket low-voltage components. A half-lap (see Figure above) consists of overlaying each turn by one-half the width of the tape. The general rule of thumb calls for a tape thickness of 1.5 times the thickness of existing wire or cable insulation. In every case, tension on the tape should be sufficient to conform the tape evenly to the surface. A slight reduction in tension is encouraged for the final wrap. Trim the tape end and allow it to return to shape before pressing down with the thumb to avoid lifting or flagging.