I know little about panel boxes. Garage light went out, bulb ok, seemed to be panel box. Box is round fuse type so I figured it should be replaced. Disconnected it and touched feed wires to circuit wires and the light didn't come on. Connect feed wires to and outlet circuit that has fluorescent light, and it hummed and was so bright. The circuit that has the light in it also has an outlet. I plugged a fan in and that sped fast but the light still wasn't on. The feed wires read 250 amps. Is it thpanel box that splits t he amp for a 120 circuit.