Saying that they can’t be supplied but multi-wire circuits is nonsense. The panel supplying these branch circuits is fed by a multi-wire circuit.
Nothing personal, but now I must rant:
We've beaten this dead horse extensively in many threads here. In addition to Gregtaylor's response, I'll repeat and expand on the same points I made in the multi-wire thread:
1: The impedance of the neutrals at feeders and panel buss are (electrically) significantly lower
than the #12 or #10 branch circuit wiring thus allowing any noise or harmonics to be "absorbed" (Not exactly the right word I'm wanting, but you get the idea);
2: ANY electronic load of ANY kind is far more sensitive to power quality issues than incandescant lighting or pure resistive loads like heating devices;
3: Electronic dimming controls of any make or style are VERY noisy (just take a portable AM radio near any of those things and you'll see what I mean.);
4: Most of these systems are extremely expensive
and sophisticated in their control schemes and do not take kindly to noise issues on incoming power (not to mention the risks of a lifted neutral frying everything); and
5: Candidly, and this is not directed at any specific person,
but I have a real problem with the attitude of trying to save a few bucks in copper on such high-end work!
Finally, if the manufacturer says don't do it, then don't do it! There are reasons for such instructions.
This issue really gets me going, and like I said, it's not personal but c'mon, how much does one really
save on these jobs by using multi-wire?
O.k., rant off.