Calculators

NEC® references are cited where a section applies. These are screening tools for preliminary design. Interim defaults, pending review.

• 3-phase currentLine current from kVA, or from kW and power factor.
• Fault current and rating checkScreening-level available fault current by the point-to-point method, compared with the rating you select.
• Generator step-load dipTransient voltage dip from a simplified reactance model, with a linear comparison.
• Feeder sizing and voltage dropConductor size from ampacity rules, plus Chapter 9 Table 9 effective impedance.
• Transformer sizingStandard kVA from the load, demand, growth, and a target loading you choose.
• Redundancy capacityUnit count and loading for N, N+1, N+2, 2N, 2(N+1), distributed xN/y, and block/catcher.