jpmst3 makes some good points
Originally Posted by jpmst3
I am running two pro amps AND a 5 x 200 main amp off of one circuit and it has never tripped despite hitting 120db+ all day long. The only way you would need more than a 20A circuit for each amp is if you were doing some kind of torture testing on the amps and or drivers.
Originally Posted by Looneybomber
Umm. That's impressive. What pro amps?
For obvious safety reason, I can't recommend it. However, it's truly fascinating knowing how much audio amplification one can get away with on a single circuit.
Looneybomber, I realize that you likely already know, but it may help others so it's worth repeating.
Due to motors requiring large amounts of current at start up, etc., breakers can pass mammoth amounts of current for brief periods of time, ... brief, yeah, but still entirely long enough to supply your gear without nuisance tripping.
I've experimented thusly, and powered everything I could find in my room on one circuit. All my front end gear, like my big Onkyo 5509 pre/pro, the rest of my stack, two high power, gaming PCs workstations, 65" plasma display, my entire active sound system comprised of (4)1kw surrounds, (3)2 kw LCRs, (2) 2kw EP4000 amplifiers, (2)2.4kw amps for subwoofers, all that ... no tripping.
For obvious safety reasons, I certainly don't recommend doing so, but the breaker will pass a great deal more than one thinks. Circuit breakers can pass extraordinary amounts of current for brief moments, ... similar to those encountered in audio playback. Having been professionally involved in both the electrical field, and in large event power/pro-audio, etc., I've seen the results of over-current scenarios of every conceivable type. Also, and most relevant to this discussion, I've performed experiments at home with my gear and residential circuits.
Again, no it's an unsafe practice, but one can utilize many times the rated ampacity of a circuit breaker for the short bursts that typically accompany audio usage.
Typical residential breakers, like a 20amp circuit breaker;
Can pass 7-8 times the rated 20amp trip amount, .. for up to a second or more.
It can pass up to 3x the rated amount for up to 10sec or so.
The same 20amp circuit, can allow up to 1.5-2times the rated amount for a period extending as long as 30 seconds.
~140-160amps for up to 1 sec
~60amps for about 10secs
~30-40amps for as long as 30secs
^ Those are extraordinarily high amounts. But it's primarily all about the deepest of the LF. Considering every octave lower the material plunges, the woofer(s) are required to move 4 times the amount of air to maintain the same playback SPL. That 400% extra displacement also requires huge current increases feeding the amplification.
From the huge numbers a breaker will allow seen above, we know the current is available, but only for short periods. So we can see that maybe the deepest sustained material, like test tones, will tax the entire system to the point where the breaker does it's job and opens up.
Now, there are performance issues. A circuit loaded up like that exhibits voltage drop, not good. For the best performance/optimal fidelity, headroom is good even with the circuit feeding your amplification.
For an experiment, I've placed everything I've got on one circuit ... and cranked it up to attempt to elicit a breaker trip. That's 6.8kw for subs, 10kw for all active mains/surrounds, 16.8kw, full tilt no problem w/breaker tripping. Actually, for that experiment there was a lot more on the circuit too ... all my remaining HT gear, plasma, multiple PC workstations (high power PCs).
Now I have multiple dedicated circuits, that was merely an experiment. Safety is a real issue, and voltage drop is a performance issue, best to be avoided (subtle yes, but a problem nonetheless). Upsized wire size on subwoofer amplification circuits is helpful.