WIRES BETWEEN PANELS PROTECTED ON LINE SIDE ONLY, not by load side breaker?

[1capybara]

Is This is an America code [NEC] code thing only? Or does 17th edition or IEC
have the same thing?
A wire runs between 2 panels is rated to carry 400 amps.
Its fed from a 600A breaker on the line side, and has a 400 Amp
breaker on its load side [the panel being fed from the other one].
Under NEC, we would say thats a code violation because
"a wire is only protected by its line side [feed side] breaker."
Meaning the correct breaker on the wire's load side doesnt
count at protecting the wire.
does 17th edition or IEC say the same thing?

 

[KFH]

The 17th edition says “ a device for protection against overload shall be installed at the point where a reduction occurs in the value of the current carrying capacity of the conductors” It does however then allow exclusions “The device protecting the conductor against overload may be installed along the run of that conductor“ followed by a series of conditions one of which is the max length of 3metres. This, I believe, is to allow for the branching from a riser to be fused in a convenient position away from the riser with a reduction an CSA of the branch cable to that of the riser.
Not exactly the scenario you describe but as close as the regulations get.
Hope above is of help