Am I eligible for getting OBC Non creamy layer certificate?

-I am Kaviyarasan, 27 years old, Diploma Holder. I belongs to OBC category. Right now I am working in one multinational company. I get 27000 rs/- per month (Yearly 3.24 lacs). I want to apply BHEL supervisor training. my father don't have any employment because he is aged, mother is a house wife. We don't have own land & any other income. For applying BHEL central government job, Am I eligible for getting OBC Non Creamy Layer Certificate? Where(which office that means thasiltar office or other office etc.,) Can I get this Certificate? What are the documents can I submit for getting this certificate? Is it easy to get certificate or too tough? Kindly guide me to get this certificate. Is it normal to get central government job, If this certificate is not provided?