Audio Systems: Shorting out., rca connector, gauge wire

Question
I start my car and all my speakers work fine. About 10 minutes later my sub keeps kicking but my speakers turn off. NO SOUND comes from the speakers.  Is this a short problem or am I not getting enouhg power from my car?  I installed a second amp, 60X4 about 2 weeks ago.  Should I get a capacitor, or is this a problem w/ my wiring?  

Answer
first thought is you dont have large enough wire for power and ground. ground should be as short as possible with large gauge wire. secondly, check all connections, including how tight are the rca connector grounds? (mine kept cutting out untill i tightened these) third, and should've been first, does the amp have enough output so you dont have to crank it up and cause it to shutdown due to heat?    g....