I'm not so sure that installing a 'commercial' appliance in a residential setting (or the opposite) is, in and of itself, a violation of 110.3(B).
In my opinion it is one of the most basic violations of 110.3(B)
I also know many inspectors feel the same.
I only dwell on this because there is a fairly large group of folks out there who actively seek "commercial" appliances
Yes that is absolutely true, and I know for a fact that some of these people where very disappointed when they found out the expensive commercial unit would not pass inspection of either the electrical or gas.
That is why manufacturers have stepped up and now sell units that 'look' commercial but are listed for residential use.
I am at a total loss why anyone would think a unit with a UL label that says 'Commercial' would be OK for Residential.
To me that would be the same as saying a unit labeled "indoor use" is just a suggestion.
