I was required to replace three regular breakers in my subpanel for a shed to GFCI breakers and now nothing works. What am I doing wrong. I put the white wires in the bus bar dedicated to neutral wires, the black wires were attached to the breakers, the ground wires to the ground bus bar. I have never worked with GFCI breakers, they have an additional white wire attached to them. I placed that white wire into the same bus bar for the white wires coming into the panel. Could this be the problem? If not, please help.