Modular shelving systems, magnetic electrical connectors, conductor assemblies, and mounting inserts are disclosed. A modular shelving system includes at least one shelving module, a power module coupled to the at least one shelving module, and a conductor assembly coupled to the at least one shelving module and electrically connected to the power module. The conductor assembly includes a board including a first column of apertures and a second column of apertures, a back plate formed from a ferromagnetic material or from a magnetic material, a first conductor electrically coupled to the power module and positioned between the back plate and the board, and a second conductor electrically coupled to the power module and positioned between the back plate and the board. The first conductor is aligned with the first column of apertures of the board. The second conductor is aligned with the second column of apertures of the board.