Electrosurgical system that includes an electrosurgical instrument (12) and an electrosurgical generator (10), the electrosurgical instrument comprising at least the first, second and third electrodes (4, 6, 7) separated from each other by the insulating element (5, 8 ； 36) between them, the first electrode (4) having a characteristic such that it is adapted to constitute an active electrode, the second electrode (6) having a characteristic such that it is adapted to constitute a first return electrode, and having the third electrode (7) a characteristic such that it is adapted to constitute a second return electrode, the electrosurgical generator including a radiofrequency energy source (60) capable of producing a coagulation RF waveform or an RF waveform of cut, and first, second and third output connections (62A, 62B, 62C) connected to the first, second and third electrode respectively of the elec instrument In addition, the generator comprises a switching means (62) having said first, second and third electrodes (62A, 62B, 62C) as outputs, and a controller (72), the controller being such that when a form of RF cut-off wave, the switching means directs the cut-off RF waveform between the first and second output connections but not the third output connection, such that the RF cut-off waveform is supplied to the first and second electrode (4, 6) but not to the third electrode, and when a coagulation RF waveform is selected, the switching means directs the coagulation RF waveform between the first and third output connections and , therefore, to the first and third electrode (4, 7).Sistema electroquirúrgico que incluye un instrumento electroquirúrgico (12) y un generador electroquirúrgico (10), comprendiendo el instrumento electroquirúrgico por lo menos los electrodos primero, segundo y tercero (4, 6, 7) separados entre sí por el elemento aislante (5, 8； 36) entre ellos, teniendo el primer electrodo (4) una característica tal que está adaptada para constituir un el
