CEI 11-35 AN ERROR IN THE GUIDE?
If I am correct identification of a section of 28 sq. mm, the guide CEI 11-35, Guide for the execution of the electrical boxes user page. 52 of the first edition, it offers enough to withstand the short circuit of the power cable of a transformer downstream of the main switch of a MV / LV, but may be inappropriate, so in a workmanlike manner and also dangerous.
We face a example of a system designed according to a rule derived from a standard IEC force, but not in a workmanlike manner. In fact it is not enough to design according to IEC, to define this activity in a workmanlike, if a trivial and almost due consideration of the working hypothesis does not permit application of the proposed rule, even though from an authoritative source.
The audit by the CEI 11-35 does not take into account the fact that energy dissipation should be calculated taking into account the transient fault current, whose contribution due to the small time to consider (100 ms) and the low value of power factor (0.1) of the network, which feeds the fault, is not negligible.
One wonders how it is possible that serious errors can find space in important legal documents. The answer is simple, but do not know why, all are afraid to give it.
