llinellau sy'n cynnwys 2 nod priflythrennau yn olynol

I have an Excel document which contains of several text lines (column A has the line number, column B is the text line)
I want to know which line (in column B) have more than 2 uppercase characters in a row, starting on each line at position 8

My name: Marianne (this line doesn't validate)
My name; MARIANNE (this line validates)

Each line which validates should be marked in column C.

I couldn't find to do this. Can anyone help me?

Cofion gorau,
Marianne