Unless your amp is 1000 wpc or more, if you use 30 amp circuit breakers, you run the risk of burning down the house before ever tripping the 30 amp circuit breakers.
On the other hand, I like to float most of my grounds, so I guess I really shouldn't talk.
You can still request 10 gauge and run a more reasonable 20 amp circuit suitable for the greatest dynamic current draws of 99% of the amps out there.
In addition, you should never need more than 15 amp circuits for each of your other components (except perhaps a subwoofer). Implying that you should reap greater benefits if each component is on it's own seperate 15 amp circuit (with the amplifier on it's own 20 amp circuit).
Digital sources inject a lot of digital noise back into the lines. Therefore, you definitely should put the digital source on it's own dedicated line. And you should not have anything sharing the line with your amplifier.
In summary, you should request, at a minimum, 3 dedicated lines. One 15 amp for your digital source, one 15 amp for your preamp, and one 20 amp for your amplifier.
And idealistically, since the electrician is already there, you might request a second 20 amp dedicated line for your subwoofer or second amplifier(or future growth) and another 15 amp dedicated for your tt, tv, or whatever.
And find the best 10 gauge and audio-grade outlets you can find for your electrician to use. Even very good 10gauge is pretty cheap and chances are your electrician's 10gauge won't be any better than Home Depot's run-of-the-mill 10gauge.
-IMO
