what gauge is your power wire?? for a 1000 watt rms system, I'd recommend at least 1ga wiring. 4ga will be cutting it close. Just make sure you fuse 12" from the battery and fuse within 8" from your amp.
What's the total number of amperage of fuses on your amp?? I'd also recommend using an ANL fuse holder and an ANL fuse. AGU fuses only go to about 80a. I did find 100a AGU fuses online, but they're not that reliable. ANL or Midi fuses are more reliable but still suspectible to popping. A circuit breaker is the most reliable and saves you on having to buy more fuses.
I had an AGU fuse holder that melted from running my system at medium to high volumes for more than an hour. I switched to an ANL fuse holder with 150a fuse and so far no problems.
AGU fuse:
ANL Fuse:
AGU fuse holder:
ANL fuse holder: