Inspectors in my department tell me a sleeve is something to protect a wire when going through a wall or floor. A raceway is something that goes from j-box to j-box, typically. They also tell me that sleeves don't have to be grounded but raceways do (if they're metal).
well 300.4 mentions 'sleeve'
multiple times in regards to physical damage, ans 250.86 is where 'short sections'
niether are in definitions, or the index of the nec.
apparently this is where pipe fill and detrating take a hiatis, at least to some (and this particular some teaches code updates btw)
For instance, let's take a simple cellar romex job that incorporates 1/2" deep 4 square devicing boxes with 1/2" emt 'sleeves'
the romex is not
stripped, because it is not
captive at the upper end of the 1/2" emt. Note the type/style of connector here would make all the dif....
another example might be an underground service riser on a poco pole. These
being considered an 'open' entity that allows heat out.
I've noted the pocos are great on V-drop, yet somewhat fall short of the nec pipe fill doctrine