disclosed herein is an engagement system for bulk power assemblies . the system comprising , a first bulk power assembly and a second bulk power assembly having equal numbers of electrical terminals and guide bosses . the system also having a rigid interface member having a first end and a second end , both ends having an equal number of terminal blades as there are electrical terminals on the first bulk power assembly and an equal number of guide blades as there are guide bosses on the first bulk power assembly . the terminal blades being receptive to make an electrical connection with the electrical terminals and the guide blades being receptive to engage with the guide bosses , in response to the interface member being functionally engaged with both bulk power assemblies simultaneously .