An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. Electrical crosstalk between neighboring capillaries is attenuated using a protective tubing formed from an electrically insulative material. This crosstalk attenuation is provided in the form of sheathing, either around individual capillaries, or around bundles of spaced apart capillaries. Crosstalk attenuation may be enhanced by passing a nonconductive gas or liquid through lumens formed in the protective tubing, in which lumens the capillary tubes are present.