Can you please tell me where I can find the diagram for the intertherm central electric furnace terminal box. I need to know where all the wires running from the therastat goes. I have a RC RH W C G on the tstat line. What wires go where?

If you can't find a diagram on the furnace or in an owners manual, I can only suggest their website. But you may not need it if it is a furnace and not a heat pump. Most furnaces have terminals similar to your thermostat. R comes from the transformer and connects to RH and RC too if you have A/C without a separate transformer for it. C is common, the other wire from the transformer.

There is a sticky note at the top of the main HVAC page that describes what t-stat wires do. Be warned installers use what wires they have available to them, not the standardized colors.