Abstract: In a sidewall-enclosed electrolytic cell, such as for the electrolysis of brine to form chloralkali product, the cell can have at least one cathode sidewall. There is now provided an at least substantially wall-sized, planar busbar that is interface bonded to the cathode sidewall. The interface bonded, wall-sized busbar plus sidewall thereby at least substantially serve as a wall unit for the electrolytic cell. The wall-sized busbar has at least one internal passageway therethrough for the circulation of cooling fluid. Where the bonded busbar is connected by a jumper switch for current connection, the cooling passageway of the busbar may connect at the location of the jumper switch.