Personal car insurance cover a rental car?

Yes you can. On the rental contract there is a box you can check that states you want to use your own coverage. Some rental places won't point this out to you because they can charge you more to use their insurance, but you not required to take what they offer and can use your own.

OPCF 27 covers rental car insurance.. as long as you have that and physuical damage coverage on your policy then your covered.