How the tools are tested

IEEE 1584-2018

• Reproduces every printed value in Annex D.1 (4.16 kV) and D.2 (480 V), including the reduced arcing current cases.
• Cross-checked on 2,800 cases against an independent open-source IEEE 1584 package, itself verified against Annex D and the official IEEE spreadsheet: all 5 electrode configurations, 208 V to 15 kV. Agreement to about 0.0002%.
• Matches SKM within about 0.1% on two test cases.

Short circuit · voltage drop · IEEE 519

• Fault current at every bus matches an independent textbook calculation on 1,200 random networks, to rounding error: utility, transformer and generator sources, single and three phase, parallel sets.
• Motor contribution uses a full-network solve, checked against an independent impedance-matrix solution on 400 networks.
• Voltage drop checked against an independent calculation; harmonic limit tables checked cell by cell against IEEE 519-2022.
• The references were deliberately broken to prove the tests catch errors.

NEC 695.7 · NFPA 20

• Starting and running drop match an independent exact (phasor) solution on 3,000 random feeders, including parallel sets, MI cable and single phase.
• Never reads below a model of the motor as its locked-rotor impedance, over 12,240 realistic starting cases.
• Step-down transformer impedance is included in the starting check, verified by hand calculation.
• Motor currents checked against NEC Tables 430.250 / 430.248, code letters against 430.7(B); 17,000+ checks.

NEC Article 220

• Matches every NEC Annex D dwelling example it computes: D1(a) standard method, D2(a)/(b)/(c) optional method (heating, A/C, heat pump), D4(a)/(b) multifamily per unit and feeders, D5(b) at 208Y/120 V, and the D6 range demands.
• Service conductor sizes match D7 for all 11 ratings from 100 to 400 A.
• 56 Annex D checks plus 50 hand calculations.

Neher-McGrath · IEC 60287

• Matches an independent implementation (different solver) within 0.003 °C and 0.1% ampacity over 1,500 random banks.
• Compared with NEC Table 315.60(C)(11) over 120 cells; the grouping effect between 1, 3 and 6 ducts matches the table within about 4%.

NEC 310.15 · Chapter 9

• Table values checked against the printed NEC 2023: 310.16, Chapter 9 Tables 4, 5 and 8, and 250.122.
• Derating, conduit fill, breaker and EGC sizing checked against hand calculations; 622 checks.