Abstract: A collecting electrode panel assembly (20) comprises a plurality of collecting electrode plates (22) disposed in successively aligned relationship beneath and suspended from an electrode support member (14) supported by the housing (12) of an electrostatic precipitator (10), such that the collecting electrode plates (22) making up the collecting electrode panel assembly (20) extend downwardly in a substantially vertical plane into the precipitation chamber (6) defined within the housing (12). Each of the plates (22) has a pair of spaced end members (24) and a central web portion (26) which extends between and interconnects the spaced end members (24). Coupling means (50) are disposed between the facing opposed end members (24) of successive plates (22) at least one location along the vertical interface of successive plates (22) to restrain bowing or warping of the assembled collecting electrode panel (20) and to keep the collecting electrode plates (22) in a common plane.