Weird shared nuetral w/ double breaker
I was in the process of installing a transfer switch that switches both hot a neutral wires on the circuit when I ran into a strange configuration. The circuit in question has a double pole 15 amp breaker with the white wire from the circuit going into one breaker and the black going into the other. My assumption was that these were two circuits with a shared neutral running back to box fron another circuit somewhere in the house. However, when I disconnect the black wire from the breaker and leave the white wire connected the circuit seems fine. When I disconnect the white wire leaving the black connected the circuit appears dead. I'm not sure what is going on and I'm not sure what the black wire is supplying when connected to the breaker as I can't find any outlets, lights, or appliances down when the black is connected. This begs the question, where is the power in the black wire going? Any help would be appreciated.