My understanding for an ENT conduit (other than for future flexibility) was that it was fire-rated, to reduce the spread of fire/air-flow between floors. If the conduit went through fire-blocks or floors, holes would have to be sealed with fire-retardant sealant/caulking.
But I always come across images like this:
or this:
Note the low-voltage backless gang boxes.
Doesn't the backless gang box defeat the purpose of fire blocking? If a fire starts in that section, it has no obstruction to enter the ENT conduit (through the backless gang box) and go all the way wherever the conduit leads to? What was the point of sealing off the floor/fire-block hole then?
Best Answer
I'm not a fire expert, but I doubt fire will actually spread through the conduit. Toxic fumes, sure, but not fire (unless the conduit is really short). Flames will, however, quickly jump through a hole in a 1 1/2" - 3" thick barrier.
If you really want to take fireblocking to the extreme, you could seal the ends of the conduit around the cables with fireblocking material.