As stated, the above approach is unsuited to industrial customers. A large number of tests using the mathematical model presented here give as reference points the values from Table 13 – which were calculated conservatively. Installation method A2 allows the smallest loads, and installation method C the largest. These benchmark figures were therefore included here. All other values are in between.
It will generally suffice to estimate the load profile of a specific consumer or part of an installation and then, if necessary, over-dimension the cable in accordance with Table 13. If a more accurate figure is required, Table 13 can be used to estimate whether a more precise calculation is worthwhile.
This assumes currents requiring, for thermal reasons, a conductor cross section of 4 mm² applying the respective installation method. Under these assumptions, the table looks somewhat “unobtrusive”, but the following remains to be considered viewing it:
- Within this range of the standardized conductor cross sections, an upgrade by 4 degrees already represents 6 times the cross section!
- Towards larger conductor cross sections the tiers become less coarse; expressed in standard sizes, the lifetime optimisation would comprise an upgrade by even more sizes.
- Anyhow, a single-case calculation will sooner be worthwhile towards larger cross sections. The generic approach presented here will be more adequate for smaller cross sections.