So the sections in 430 that let you size differently than what 240 states, do not apply to this situation?
imo it would apply since it is the feeder portion of the motor circuit and governed by 430 (the VFD is the controller)
so you could size the conductor at 1.25 x FLC
and the OCP at 250%
all 2011
Table 310.15(B)(16) lists #10 as 35 A at 75C
a ** footnote says to reference 240.4(D) for OCP limitations
it says 30 A OCP unless an exception exists for specific conductors
240.4(G) ref table 240.4(G) motor and motor control circuits are excepted and governed by 430 Parts II, IV, V, VI and VII
Part II conductor sizing
Part IV branch OCP
part V feeder OCP protection
it would seem the OCP can be sized per parts IV and V (IT CB basically 250% x flc
and the conductor per part II, basically 125% of the motor or vfd flc
without knowing the flc a 40 CB and #10 would seem fine for a flc <40/2.5 = 16 A
conductor 1.25 x 16 = 20 A < 35 A #10
so if flc <+ 16 A good to go