confirmation time tc lt t 1 as described with respect to fig4 as such this case is common to the main generators and the auxiliary power generator in one embodiment agen power transfer can proceed with an absence of u201c handshake protocol u201d due to bpcu single failure with no other power sources present in this case a bus power transfer protocol will not issue request for a btc lockout due to the absence of the other power sources in this case regardless of btcs open closed status an agen will complete power transfer after ti time in one embodiment agen power transfer can proceed with an absence of a u201c handshake protocol u201d due to bpcu single failure with one or more ac power sources present in this case the different btc arrangements and ac bus power sources can create multiple configurations which can create a conflict in one group of configurations ac power from the main generators is present on either the lac bus or the rac bus see lac 155 and rac 160 in fig1 for example the status of all two btcs is arbitrary one out of four btcs combinations can cause conflict and in this.