H1B CAP EXEMPT guide lines


I am holding a H1B petition was having validity Oct 2016- Sep 2017 from Employer A. This is my first H1B petition.

My H1B is not stamped yet and have never travelled to USA.

My question is once my petition is expired that is after Sep 2017, If i apply for H1B again from employer A or B in future, Do i need to go thru the lottery system again or will that be a cap exempt petition?

Or is it advisible to join company B and approach Company B to transfer the H1B, in that case is there any time line to apply for transfer petition?

In both the cases am i eligible for CAP exempt petition?

Please advise. Its urgent.