It is critically important to properly install the DC rectifier output polarity before energizing the rectifier or power supply. The DC positive must always connect to the anode system. And the DC negative must always connect to the structure lead(s) connected to the structure. To repeat, the anode must always connect to the positive. The structure to the negative. If the anode and structure leads are tied to the opposite polarity, current will be driven off the structure and towards the anode system. This could be catastrophic, causing accelerated corrosion of the structure. For steel this would be at the rate of 20 lbs/amp year.