Section 240.4(B) applies only up to 1000V?


Senior Member
So the next size up rule, to the best of my understanding, applies to installations up to 1000 Volts.

This is due to Part IX "Overcurrent Protection over 1000 Volts, Nominal"

The interesting part is section 240.101(A) - "The long-time trip element setting of a breaker shall not exceed 6 times ampacity of conductor"

So the way I understand the above referenced sections is that in medium voltage applications (over 1kV) you really don't need the size of the conductor to match the OCPD rating (as long as it's not more than 6 times smaller)

Would you agree with the above?