J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Electrical ground

John - the DC return at the DC Switch panel should be a direct run back to the battery negative terminal. I suspect you have a bad crimp connection, lug, or connection, as it is uncommon for the wire to break unless it is right by a connection. If you have had other issues, you may see burnt insulation, but you would see signs of that and would have smelled it. Try checking the connections at both ends first with a meter.