And lets not forget that code (at least in commercial situations) is that breakers should not be loaded to more than 80% of their capacity on a continuous basis.  So a 20 amp, 110V circuit (typically using 12 gauge wire) should not have more than 1760 watts of continuous load.  Basically one S4/s7/s9 per 20 amp circuit.  That limit is 1320 watts if your running with a 15 amp breaker (and typically 14 gauge wire).  E.g.  Your really pushing your circuits if your running an S9 at over 11.83THs.   Maybe that is why they came out with that box?  So it would, barely, fit on a typical US home circuit?