What is the grace period offered after expiry of a prepaid plan for bsnl 3g prepaid connection?
Grace period is 15 days. But your number will remain active for another 165 days when grace period expires. So, your number will remain active for 180 days after your validity expires. Ofcourse, incoming/outgoing will be barred during these 180 days.
Is the balance carried forward if renewed in this period?
Yes. 15 days - that's it. You lose all your balance on the 16th day.