Wire Bending Space vs Conductor Bending Radius

[LPS]

I'm building a 125HP enclosed VFD panel with a high SCCR (meaning large power distribution), bypass contactors, 400A disconnect, line reactor, brake module, and other miscellaneous devices. On top of all that, I'm required to provide 20% spare space. Because I have to show all this on a layout, I need to squeeze everything together. I'm really looking close at the wire bending space. The 125A motor circuit will be using 3/0 conductors. UL 508A only seems to cover conductors entering or leaving the enclosure. The same appears to be true of 312.6. I can't find anything about the conductors that begin and end inside the enclosure. Can anyone comment on this? Over the decades, I have seen a lot of very tight internal wiring on large power control panels, so maybe that's the reason they can get away with it. Maybe there are no restrictions...?? Also, this section only seems to refer to "wire bending space". It doesn't say anything about the bending radius of a conductor. In other words, you just have to provide the space. You could bend the wire sharper (within reason) if you want. 300.34 does have conductor bending radius requirements, but that's for conductors greater than 1000V. I guess we would have to comply with conductor manufacturers instructions, but I haven't got that far... Thanks in advance.

 

[infinity]

From my experiin working on hundreds of them I'm guessing that there is no NEC guidance when it comes to sizing the wiring compartment on a VFD. They almost always seem to be too small and as I'm cursing up a storm during the wiring process I'm trying to understand how some of these junk products can actually be listed.

 

[jim dungar]

600V conductors with insulation like THHN and MTW bending radii would come from the manufacturer. As far as I have seen, these insulations can be bent at sharp 90° angles with effectively no radius.

It is only the field terminations areas that is subject to the NEC dimensions.