I simply adopted your own country philosopher Sir Bertrand Russeli's statement that some American millionaires think themselves as gods, implying that with their huge amount of money nothing is difficult to them.
More seriously, I am wondering. with high proliferation of single phase harmonic producing electronic loads in any building, how it could be possible to contain them within 10%.
I would think it more important to use mitigating measures to prevent the harmonics from polluting the supply network to the building rather than puting a limit on harmonic producing load within it.
However, there are ways and means to reduce the harmonics produced by any piece of kit. You mentioned a sine wave input SMPS in another thread. Use that technique in all electronic gizmos - job done. More expensive but done.
An alternative approach is to run things like computers from a UPS (we do our servers that way) with a sine wave input.
Any drives van be active front end.
Anything can have a passive harmonic filter included at its input.
And, I ought to ask you what the 10% refers to? Power rating? Current distortion? They're not the same thing.