I think we need to focuson the WHAT we're trying toaccomplish, and the WHY, and not get bogged down in the details.
Let's first ask: what is a 'sleeve" supposed to do? As best I can tell, it's there primarily to protect the wires from damage, and perhaps secondarily to ease the installation of those wires.
If that's the case, then the sleeve has, as it's first priority, to be able to withstand whatever it is we want to protect against. An errent staple is one thing; a backing up semi-trailer is another. Or, the sleeve may be there to keep the wires from getting in harms way; an example might be the tubes used to keep wires around your car's engine from getting caught in belts, etc.
I would like to observe here that UL does NOT have a listing classification for 'sleeving.' Let's not make the leap and assume that 'conduit' is always a good material for a sleeve.
However the sleeveis made, two other criteria need to be met.First, the wires need to be protected from abrasion where they enter the sleeve. Second, they need to be secured.
