Ok, 300.34 reads,
300.34 Conductor Bending Radius.
The conductor shall not be bent to a radius less than 8 times the overall diameter for nonshielded conductors or 12 times the overall diameter for shielded or lead-covered conductors during or after installation. For multiconductor or multiplexed single-conductor cables having individually shielded conductors, the minimum bending radius is 12 times the diameter of the individually shielded conductors or 7 times the overall diameter, whichever is greater.
The top potion is discussing single conductors and the potion discussing the multiconductors or multiplexed shielded is what we are dealing with.
As strange as it my seem the contractor, believes that the calculation refers to one cable, but I contend that it is refering to all 3 cables in the multipex (triplexed is what the cables are configured). The difference is great when you speak of all three cable diameter, instead of one of course. In this case the single conductor 500kcmil EPR Shielded Cable diameter is 1.38 by the manufacturer detail, that would mean that the bend radius would be somewhere near 49" inches. I just wanted to know the correct interpretation of the code. Is it the one single conductor or all three in the multiplex configuration? My calculation would look like this:
MV cable diameter = 1.38" X 3 (number of MV cables in the multiplex) = 4.14"
12X4.14" = 49.68" bending radius
The code is definitely concern with maintaining the protection of the MV cable, by stating of the two calculation take the one that has the greater bend radius. So it is clear they are not trying to give any allowances on the bending of the cable and I am talking about a 4160V cranking motor.
The bend radius may not come into play today or even a year from know, but maybe a few years down the line, my company would be absorbing the cost of replacing the cable and a shut down of the Units, if the MV cable is damaged because of a bad install.