An edge grinding unit for machines for working the edges of plates in general and of glass sheets in particular comprising at least at one rim of a plate being worked, a grinding wheel which is accommodated in a carousel element provided with a rotatable cage formed by a plurality of circumferentially distributed rollers. This approach uses satellite imagery, GIS data, automatic image processing, and predictive modeling to determine the location of the hazards automatically, thus optimizing infrastructure management. In at least a part of a portion of the electrode bar embedded in the sealing portion, the entire outer peripheral surface thereof is covered tightly with a metal-foil sleeve 7a.