A safety arrangement of an elevator and a method for monitoring electrical safety in an elevator system is disclosed. The safety arrangement of an elevator includes a motor drive having a main circuit, an accessible conducting part, which is earthed, an insulator, which is adapted to electrically insulate the aforementioned conducting part from the aforementioned main circuit and also a monitoring circuit, which determines an earth fault of the aforementioned main circuit occurring via the conducting part. The monitoring circuit forms a signal indicating the danger of electric shock in the motor drive of the elevator, if the earth fault is diagnosed.