Australian phantom users?

[yesgrey]

Does that mean if I use a 10Amp cable I will only be getting 10A * 240 = 2400 Wattage (theoretically), despite the Silver phantoms able to produce sound as sleach says?

First, the current capacity of a cable is a thermal limit, which means that if you exceed it for too long the cable (conductor) will start heating and it might end up melting. Any cable can handle any current, the only difference is for how long until it melts. So, no, don't worry because the cable will not limit your Phantom output.

Second, the 3000w are peak power, not continuous, so, I guess the right formula would be 3000W / ( sqrt(2) * 240V ) = 8.83A, which is less than the specified 10.

Having said this, you should not worry, because you would rarely use all the 3000w peak power, and, in the unlikely few times you might use it, it would be for such a short period that the cable wouldn't even get warmer...