I'm before making my rear engine lid. As the lid got place for rear number plate I was thinking if I could insert wireing underneath the CF bonnet. 
I know normally heating in aerospace is installed inside the composite part and on the ends are plugs.
Is it possible just to use normal wires? But then it will have to come out through the bag to not being soaked with resin.
Distance I'm thinking of is with red line.

I wouldn't, you're making life very difficult for yourself, especially for infusion. Why do you want to do it?

I built race car parts with integrated electronics and cables in infusion and prepreg. It is certainly possible, but for your application i cannot see the advantage. I would rather integrate a cable channel so you have a neat solution to hide the cables, but everything remains independent so you can switch things out.

Lot of the f1 floors have silicone cable bonded in the laminate.
Pulled out after cure an the wiring/pressure taps then threaded through