I am installing a new thermostat and there is no power to the c wire. The c wire seems to act as a ground. I get 28 volts between the c and r wires. Is this normal? I was looking at the transformer on my furnace and there are 2 leads coming out. A fused blue lead that connects to the c terminal and a yellow lead that connects to the r terminal. There is also a wire connected to the c terminal that is screwed into the box like a ground. Is this normal? I was under the impression that the c wire for the thermostat is supposed to be a 24 volt positive wire. Any help is greatly appreciated!!