Looking for a ground wire

enblethen wrote:
You must not confuse what you are calling ground.
A ground for the AC system is a safety wire that is not a current carrying conductor.
A "ground" for a DC system is a negative current carrying conductor.
Some thermostats have an isolated DC "negative" conductor.

Yea, I see what you're saying. The Tstat "ground" may not be common to the converter negative return, which is what I'm looking for. I'll investigate this further in a few weeks and let you know what I determine, if interested.

As far as you other guys, stop with the derogatory comments and insults. It's annoying. It's the main reason I stay away from this forum most of the time. I came here to get advice from Doug and Old Biscuit, not to be insulted or have to read insulting gibberish.

Thanks for everyone's input.