I once had the Personell director of a company composed of engineers say "what good is an English major?"
I think that the lable is using poor English. I believe that what they meant was "install on a dedicated circuit."
While this may not be a specific code requirement, the other requirements for overcurrent, wire sizing, disconnecting means, etc., are a lot easier to meet if you have a dedicated circuit!
One exception, that I am willing to entertain, is having associated equipment (filters, humidifiers, etc.) and the furnace blower on the same circuit. These are arguably part of the same system...
