An electronic device for the diagnosis of insulation loss of an energized electrical apparatus, with respect to a ground. The device includes a first resistance-switch group and a second resistance-switch group, connectable or disconnectable in a controlled manner, and also a first measurement circuit and a second measurement circuit, arranged in parallel to the first and second resistance-switch groups, respectively. The first and second measurement circuits include respective first and second detection circuits, first and second charge modulation circuits and first and second partition resistors (RBminus, RBplus). The first and second charge modulation circuits allow a dynamic “switching” measurement technique. Moreover, a method is described for measuring the insulation resistances (RIminus, RIplus) of an energized electrical apparatus with respect to ground, in which the method is carried out by a device according to the invention. Finally, a self-diagnosis method of device is described.