This installation meets the NEC requirements because the cross-sectional area of all conductors is less than 20% of the cross-sectional area of the auxiliary gutter and there are no more than 30 are current carrying conductors.  In the above example, the signal circuit wires are not Class 2 or 3 circuits, but are Class 1 circuits that are functionally associated with the current carrying conductors.
 

In general, Class 2 circuit and Class 3 circuit conductors cannot be installed in an auxiliary gutter or wireway with Class 1 circuit or power and lighting conductors.  There are ways around  this rule by allowing the Class 2 or Class 3 circuit conductors to be installed in metal raceways within the enclosure or by installing a fixed barrier in the auxiliary wireway or auxiliary gutter.  Installing Class 1 or power conductors in a raceway that is installed inside a wireway that contains Class 2 circuit conductors is also used to maintain separation..