George, the exception in (A) of 310.15 was discussed in the IAEI news a while ago. The assumption is the thermal conductivity of the conductor will tend to average out the hot spot. In that regard I don't understand the new language of 336.80. I guess the CMP has the same issue you do with the exception but they won't address it.
Sometimes I think the guys who write new language do not rationalize it with old language they let stand.
