As per as my knowledge it is difficult to get in Indian Navy after completing diploma in Electrical engineering. The minimum requirement for the Indian navy is as following:

Eligibility:
The applicant should hold B.tech/BE Degree; with 60% or above marks in any discipline including civil engineering/ B. Arch./
Graduate degree with Post graduate Diploma/ Degree in Material Management/ ICWA/ CA

I would suggest you to apply for following companies rather then Indian Navy:

ECIL
BHEL
CIL
NALCO
NTPC
Or complete the qualification first.