Discussion of "1987 ampacity tables-demystifying the myths" (and reply)

J. Nasilowski observes that the above-titled paper (see ibid., vol.25, no.5, p.910-17, (1989)) shows clearly why electrical engineers do not calculate the ampacity of conductors (a very complicated job with uncertain results), preferring current heating tests with certain results. He points out that it is possible to derive from Newton´s heat dissipation law a new thermokinetic coefficient for the case of electric heating of power conductors in thermal balance. He shows that the theory is simple and is in agreement with experiments with the necessary accuracy. D.W. Zipse, the author of the paper under discussion, agrees that electrical engineers hesitate to undertake the Neher-McGrath calculations (for ampacity) by hand, since the calculations are complex, with over 80 variables, and extremely time consuming. He notes that the complexity and time-consuming factors involved have been reduced to a minimum with the availability of several computer programs, which are available at reasonable costs.<>