A crash prevention device for a machine tool for preventing the collision of a moving part of the machine tool with other machine tool parts or with a workpiece in a working area of the machine tool includes an isolation mechanism that electrically isolates the moving part from the other machine tool parts or the workpiece. The device includes a detection system with a high voltage generator having a first positive connector electrically connected to the moving part and a negative connector electrically connected to the workpiece or to the other machine tool parts. The high voltage generator generates DC, AC, or pulsating voltage. The detection system includes a discharge detection device that detects an electrical discharge between the moving part and the workpiece or between the moving part and the other machine tool parts, then sends a signal to stop or adapt further relative movement of the moving part.