Electro-coalescer systems herein may include a vessel, a base plate separating a process chamber and an electric enclosure, rod-shaped ceramic insulated electrodes, and a sealing assembly. An end of the electrodes is located within the electric enclosure. The electrodes traverse respective through-holes of the base plate into or through the process chamber, where a second portion is supported by a spacer, configured to maintain a position of the electrodes while allowing fluid passage. The sealing assembly forms a seal between the through-holes and the rod-shaped insulated electrodes, preventing fluid traversing from the process chamber into the electric enclosure. The sealing assembly may include: a metal fitting disposed around the rod-shaped insulated electrode; metal o-rings; metal seats; and a closing nut. The metal fitting has a coefficient of thermal expansion similar to that of the ceramic insulator, thereby preventing breakage of the electrodes during use.