I have just moved into my home and I replaced the two thermostats. The one in the basement had smaller wires than the one in the living room and was easy to install.

However the thermostat in the living room has thicker wires and when I installed it, it actually melted a part of the thermostat.

I am going to try again to install the thermostat in the livingroom but this time my wife is freaking out. She wants to call an electrician instead of just doing it ourselves. I am trying to reassure her that the thickness of the wire does not count and they all carry the same voltage.

Am I right?

Usually not since the amperage of the wire is so low.

Oops I have done it again. I have just installed a Hunter thermostat and as soon as I turned on the power, smoke started to come from the thermo!

I have added three photos.

One has the current wires. Notice how thick the wires are.

The second pic is my current thermo a Johnson and something.

And the third show the damage after turning the power on.

I need help!!

It looks like you are putting a 24 volt thermostat on a 240 volt, line voltage electric heater.