So you are generally correct, but that does not take the power factor into account (which Gene claimed to be 0.75 for a typical AVR). Try this calculator with sample 1,000 W loads of various non-continuous types, and a 120 V circuit single-phase AC, and see how that affects CB size. With the PF=0.75, the CB is 1.33x that with PF=1, all other things being equal. What do you think the safety factor (SF) should be for AVRs? Higher than the 75% for AC or even 100% for a welders (an even more non-continuous load)?
0.75 pf is very a very reasonable assumption, though a little on the conservative side imo (a good thing for safety). I would avoid using SF on things related to electrical safety codes because SF will typically mean service factor, not safety factor.
If you are asking about safety factor consideration for an AVR load, I don't have an answer. You can understand why if you consider some examples:
A) Someone using an AVR to power 5 speakers with 92 dB/W/m sensitivity, sitting 3 meters and listening to 10 dB below reference:
Power required = about 3.5 W, assuming eff at such low output level = 15%, power consumption = 3.5/.12 = 23.3 W, current = 23.3/120/.75 = 0.324 A, or 5X.324 = 1.62 A
B) Someone using the same AVR to power 5 speakers with 89 dB/W/m, same seating distance, same listening spl:
Power required = 7 W, assuming the same efficiency, Power consumption = 7 W/0.15 = 46.67 W, current = 46.67/120/.75 = 0.519 A, or 5X.519 = 2.6 A
C) Somone using the same AVR for the same conditions but listens to reference level (this means 105 dB peak with just one speaker):
Power required = 175 W, Power consumption would then be about 175/120/0.8/0.8 = 2.28 A, or 5X2.28 = 11.4 A
So if you consider scenario C) above, for some who always listen at reference level, at 3 meters distance using 89 dB/W/m speakers in 5 channel stereo mode, current draw will still be below 12 A (80% of 15 A).
But it depends so much on the individual's speakers and listening habit so it doesn't seem practical to consider "safety factor". Besides, it is an audio device that is protected by not only the circuit breaker, but also the device's protective system that nowadays almost always offer protection against short circuit current, overcurrent, thermal overall current, dc offset, and potentially more. Also, unlike baseboard heaters, fan, pump motors, audio devices naturally don't get as much attention from the regulatory authorities, and are not even mentioned specifically in electrical code books.
Think about his, we even have a thread on ASR named "FTC may drop the amplifier rules", that tells you how keen the regulatory authorities are on audio devices. I guess to them they are low risk, never resulted in much major accidents (may be the odd small fires), injuries etc..
https://www.stereophile.com/content/ftc-proposes-eliminating-its-amplifier-rule Seems strange and short sighted to drop the whole rule rather than modify it. Then again it appears there is pretty much zero enforcement. Still hard to see how this benefits the consumer. Heck they need a new rule...
www.audiosciencereview.com