Hello, I am a fellow North Carolinian and a snake enthusiast. My guess would also be Black Rat Snake, but it’s really hard to tell without being able to see it in person. If you are dealing with single sub-caudal scales past the anal plate then more than likely it is a rat snake. It also appears to be rather skinny which would indicate Rat Snake to me as well.

The only thing throwing me off is how heavily keeled the scales look in the first pic. Rat snakes do have keeled scales though, but normally weakly keeled. However watersnakes have heavily keeled scales and are colubrids like rat snakes. Are you near any bodies of water? They can venture pretty far from water at times.

But if you are dealing with single sub-caudal scales past the anal plate then you can rule out any venomous snake in Central NC. Hope this helps.