There is obviously something setting it off. We recently had our power redone too and had a heap of safety switches installed and if we run too much at once, or if a light blows, it will throw the switch, but it sounds like you are shorting out somewhere. Are you sure it's not the fuse itself? have you checked the powerpoints for signs that something has shorted out (there will be black powdery like stuff around it and it may look a bit melted)