A switching assembly selectively routes power received from upstream power distribution systems over power transmission lines to a downstream electrical load using data signals communicated to the assembly from the power distribution systems over the power transmission lines. The switching assembly monitors information in the data signals to determine conditions in the upstream power distribution systems. The switching assembly can use the conditions in the power distribution systems and monitored power feed characteristics of power received at the switching assembly to determine whether to command a switching mechanism to switch the power feed routed to the load. Power system conditions can be used to adjust tolerance thresholds against which power feed characteristics are compared to determine whether to command a switch. The switching assembly can include an interposer device that controls the switching mechanism based on analysis of data signals received over the power transmission line.