An electrical shunting switch assembly (12) for use with a high continuous D.C. current electrochemical cell system (10), for electrically shunting or by-passing a cell (10b) of the system to permit maintenance or replacement, and then permitting stepped or gradual current diversion back through the cell (10b). This shunting switch assembly (12) includes a plurality of electrically parallel switch modules (22) which comprises a vacuum switch (S), a series connected resistance value (R) and switch operating means for sequentially operating the switches (S) for current diversion. The switch modules (22) are disposed in a matrix arrangement connected between bus connectors (14,16) which are connectable across the cell (10b), with switch modules (22) having a low resistance value (Ra, Rc) in alternating adjacent relationship to switch modules having a high resistance value (Rb, Rd). The low resistance value modules (22a, 22c) permit high shunting efficiency. The higher resistance value modules (22b, 22d) provide the capability for stepped or gradual current diversion.