Return to the Main form and the use the "Calculate |
Calculation Options..." menu command or the Calculate icon to proceed to the
Calculation Options form. Under Type of Calculation, select "Single" and under
Parameter to Calculate select "Ampacity". In this calculation, AmpCalc will
treat all six cables as parallel conductors of the same circuit. A single
ampacity will be calculated applicable to every cable in the system. This
ampacity will be based on limiting the temperature of the hottest cables in the
installation, (which are the two positions in the middle row), to the rated
operating temperature of 75 degrees C. This is the manner in which the NEC and
S-135 ampacities are calculated.

These cables have an ampacity rating of 271.6 amps, (which is
very close to the IEEE Standard S-135 and the NEC code value of 273 amps.)