I guess you prolly shouldn't be blowin' fuses eh? I used one in my formula b/c when I would go racing I would take all the stuff outta the back (the amp rack and sub box had handles and quick disconnects and lifted outta the car) but I guess you wouldn't really need one in a permanent installation.
Are circuit breakers acceptable in competition?

*Rides*
-1999 Ford Contour SE Sport
stock ATX, best time 16.66@81mph

Pioneer HU, door speakers
Pair Cadence Ultra Drive 12s
Sony 1000 watt Class D amp

Kills:
Rockford 12" HE2 (exploded.. blew out 3 in a row, gotta love best buy protection plan :P )