An in-floor electrical floor-box assembly includes a rectangular or nearly square metallic housing and a non-metallic riser with integral flange assembly having a rectangular flange that mates with the rectangular housing and an integral cylindrical riser for providing access to the electrical components through a round cover and finish flange. A low-voltage divider assembly separates cables carrying different voltages within the riser to reduce interference between the cables and any one of a variety of sub-plates having different configurations for accommodating a variety of multi-service or single service electrical functionality can be incorporated with the box.