392.10(B)(1)(a) - Single conductor cables 1/0 or larger

[NAZ55]

What type of cables does this section applies to? Does it apply to instrumentation cables, which are covered under 727? What's the purpose of this limitation?
Any suggestions will be greatly appreciated.

 

[7anoter4]

Art. 392.10(B)(1)(a):
“Single-conductor cable shall be 1/0 AWG or larger
and shall be of a type listed and marked on the surface for
use in cable trays”.
This is not a new limitation but it was also in previous editions.
In my opinion- since the method of installation in cable tray requires a certain force to be applied on this cable if the power cable conductor will be less than 1/0 AWG it could be damaged.
IEEE 525/1992 limit the pulling tension to 1000 lbs[4.45 kN] -pulling a single-core cable with a basket-grip.
The required pulling force depends on many factors as the run length, the lubrication, the number, size and shape of the bends, and other.
Other standard as VDE 0298-1/3 for instance-limits the pulling force[basket grip pulling ] to:
P=3*d^2 [P in N, d overall diameter in mm] for single-core cable that means for 1/0 AWG approx. 500 lbs.
If there are other cables to be installed in the same cable tray pulling a larger diameter cable when the small cable is already laid it could damage the small cable. A rule of a thumb the diameter ratio has to be less than 3.