Validation
Worked examples with published answers are run through the RokBench engine on every change and compared side by side. Failing cases are shown as known deviations, not hidden. Only input values are recorded from each source.
125 V switchgear battery, four-period duty cycle with an entered K curve battery/sizing · Hand calculation
PassSource: Hand calculation of the IEEE 485 section method with the K curve entered as points (linear between points) — Periods 120 A/1 min, 15 A/59 min, 40 A/120 min, 100 A/1 min. K points (min → h): 1 → 0.9, 15 → 1.6, 60 → 2.8, 180 → 5.0, 480 → 8. S1 = 120·0.9 = 108. S2 (60 min) = 120·2.8 − 105·K(59) = 336 − 291.2 = 44.8. S3 (180) = 120·5.0 − 105·K(179) + 25·K(120) = 600 − 523.1 + 97.5 = 174.4. S4 (181) = 120·K(181) − 105·5.0 + 25·K(121) + 60·0.9 = 601.2 − 525 + 97.96 + 54 = 228.2 → × 1.25 × 1.10 = 313.8 Ah. 125/2 = 62.5 → 63 cells, 105/63 = 1.667 V/cell.
| Quantity | Expected | RokBench | Error | Result |
|---|---|---|---|---|
| cells | 63 | 63 | 0% | Pass |
| endVoltagePerCell | 1.667 | 1.667 | 0% | Pass |
| uncorrectedAh | 228.2 | 228.2 | 0% | Pass |
| governingSection | 4 | 4 | 0% | Pass |
| requiredAh | 314 | 314 | 0% | Pass |
Galvanic anodes, high-potential magnesium, 1 A in 30 Ω·m soil cathodic/galvanic · Hand calculation
PassSource: Hand calculation from Dwight's single vertical electrode equation and the galvanic anode output and life equations — ΔV = 1.75 − 0.85 = 0.90 V; Ra = 30/(2π·1.5)·(ln(8·1.5/0.2) − 1) = 9.8496 Ω; Ia = 0.9/9.8496 = 0.09137 A; N = ⌈1/0.09137⌉ = 11; life = 14.5·0.85/(7.9·0.09137) = 17.07 years.
| Quantity | Expected | RokBench | Error | Result |
|---|---|---|---|---|
| anodeResistanceOhm | 9.8496 | 9.85 | 0.004% | Pass |
| outputPerAnodeA | 0.09137 | 0.0914 | 0.033% | Pass |
| anodes | 11 | 11 | 0% | Pass |
| lifeYears | 17.07 | 17.1 | 0.176% | Pass |
ICCP, 10 A, seven vertical anodes at 5 m in 30 Ω·m soil cathodic/iccp · Hand calculation
PassSource: Hand calculation from Sunde's multiple vertical anode equation and the anode life equation — I = 10000·10·0.1/1000 = 10 A; N = max(⌈10/2⌉, ⌈10·0.5·20/(20·0.8)⌉) = 7; R = 30/(2π·7·2.1)·(ln(8·2.1/0.25) − 1 + (4.2/5)·ln(0.656·7)) = 1.4578 Ω; V = 10·(1.4578 + 0.3) + 2 = 19.58 V.
| Quantity | Expected | RokBench | Error | Result |
|---|---|---|---|---|
| currentA | 10 | 10 | 0% | Pass |
| groundbedOhm | 1.4578 | 1.458 | 0.014% | Pass |
| lifeYears | 22.4 | 22.4 | 0% | Pass |
Emergency generator: pump (DOL), lighting, two fans (star-delta) generator/sizing · Hand calculation
PassSource: Hand calculation of the PG1–PG3 method (running load, voltage dip on largest start, instantaneous load) — PG2 = 717.7 kVA × 0.20 × 0.8 / 0.2 = 574.2 kVA governs.
| Quantity | Expected | RokBench | Error | Result |
|---|---|---|---|---|
| pg1Kva | 275.6 | 275.6 | 0% | Pass |
| pg2Kva | 574.16 | 574.2 | 0.007% | Pass |
| pg3Kva | 344.3 | 344.3 | 0% | Pass |
| requiredKw | 459.3 | 459.3 | 0% | Pass |
Buried horizontal wire, 100 m of 4/0 AWG at 0.8 m in 100 Ω·m soil ground/rod · Hand calculation
PassSource: Hand calculation from Dwight's buried horizontal wire formula (as given in IEEE Std 142) — 4/0 AWG = 211.6 kcmil = 107.22 mm² → a = √(107.22/π) = 5.842 mm; L = 50 m, s = 1.6 m. R = 100/(4π·50)·[ln(200/0.005842) + ln(200/1.6) − 2 + 1.6/100 − 1.6²/(16·50²) + 1.6⁴/(512·50⁴)] = 2.114 Ω.
| Quantity | Expected | RokBench | Error | Result |
|---|---|---|---|---|
| wireOhm | 2.114 | 2.11 | 0.189% | Pass |
| totalOhm | 2.114 | 2.11 | 0.189% | Pass |
Square grid without ground rods, 70 × 70 m grounding/grid · Standard example
PassSource: IEEE Std 80-2013, Annex B, Example 1 (square grid without ground rods) — Input values only. Published tolerable voltages use Cs rounded to 0.74 and Em uses Km rounded to 0.89; RokBench carries full precision, hence the small differences. For comparison the standard quotes EPRI TR-100622 at 2.67 Ω and 984.3 V.
| Quantity | Expected | RokBench | Error | Result |
|---|---|---|---|---|
| gridResistanceOhm | 2.78 | 2.7757 | 0.155% | Pass |
| meshVoltageV | 1002.1 | 1001.6 | 0.05% | Pass |
| tolerableTouchV | 838.2 | 840.5 | 0.274% | Pass |
| tolerableStepV | 2686.6 | 2696.1 | 0.354% | Pass |
| geometry.Km | 0.89 | 0.8896 | 0.045% | Pass |
| geometry.Ki | 2.272 | 2.272 | 0% | Pass |
| geometry.Ks | 0.406 | 0.4061 | 0.025% | Pass |
Square grid with 20 perimeter ground rods, 70 × 70 m grounding/grid · Standard example
PassSource: IEEE Std 80-2013, Annex B, Example 2 (square grid with ground rods) — Input values only. Published values use Km rounded to 0.77; Rg by Equation (52) (Sverak), Em with the perimeter-rod effective length (Equation (91)). For comparison the standard quotes EPRI TR-100622 at 2.52 Ω, 756.2 V and 459.1 V.
| Quantity | Expected | RokBench | Error | Result |
|---|---|---|---|---|
| gridResistanceOhm | 2.75 | 2.7526 | 0.095% | Pass |
| meshVoltageV | 747.4 | 749.1 | 0.227% | Pass |
| stepVoltageV | 548.9 | 549.1 | 0.036% | Pass |
| geometry.Km | 0.77 | 0.7717 | 0.221% | Pass |
| geometry.Ki | 2.272 | 2.272 | 0% | Pass |
| geometry.Ks | 0.406 | 0.4061 | 0.025% | Pass |
Rectangular grid with 38 ground rods, 63 × 84 m grounding/grid · Standard example
PassSource: IEEE Std 80-2013, Annex B, Example 3 (rectangular grid with ground rods) — Input values only. Kii = 1 (grid with ground rods). The published Em back-calculates to LM = 2292.1 m, the perimeter-rod effective length of Equation (91), so onPerimeter is set. Published Em uses Km rounded to 0.77. For comparison the standard quotes EPRI TR-100622 at 2.28 Ω, 519.4 V and 349.7 V.
| Quantity | Expected | RokBench | Error | Result |
|---|---|---|---|---|
| gridResistanceOhm | 2.62 | 2.6185 | 0.057% | Pass |
| meshVoltageV | 595.8 | 593.6 | 0.369% | Pass |
| geometry.conductorLengthM | 1659 | 1659 | 0% | Pass |
| geometry.n | 11.35 | 11.344 | 0.053% | Pass |
| geometry.Km | 0.77 | 0.7675 | 0.325% | Pass |
| geometry.Ki | 2.324 | 2.3229 | 0.047% | Pass |
Lumen method, 20 × 10 m room, 500 lux lighting/lumen · Hand calculation
PassSource: Hand calculation from the lumen method equations — hrc = 3 − 0.8 = 2.2 m; RCR = 5·2.2·30/200 = 1.65; N = 500·200/(5000·0.6·0.8) = 41.67 → 42; grid 9 × 5 = 45; E = 45·2400/200 = 540 lux.
| Quantity | Expected | RokBench | Error | Result |
|---|---|---|---|---|
| rcr | 1.65 | 1.65 | 0% | Pass |
| requiredCount | 42 | 42 | 0% | Pass |
| achievedLux | 540 | 540 | 0% | Pass |
Rectangular structure 30 × 20 m, 10 m high lightning/risk · Hand calculation
PassSource: Hand calculation from the published collection-area and frequency equations (NFPA 780 Annex L) — Ae = 30·20 + 6·10·(30+20) + 9π·10² = 6427.4 m²; Nd = 4 · 6427.4 · 1 · 1e-6 = 0.02571; Nc = 1.5e-3. E = 1 − 0.0015/0.025710 = 0.94166 → protection level II.
| Quantity | Expected | RokBench | Error | Result |
|---|---|---|---|---|
| collectionAreaM2 | 6427.4 | 6427.4 | 0% | Pass |
| expectedFrequency | 0.02571 | 0.02571 | 0% | Pass |
| tolerableFrequency | 0.0015 | 0.0015 | 0% | Pass |
| requiredEfficiency | 0.941656 | 0.9417 | 0.005% | Pass |
150 kW motor started across the line on a 1500 kVA, 5.75 % Z transformer motor/starting · Hand calculation
PassSource: Hand calculation from the constant-impedance equations on the Methods page — Zt = 0.0575 · 480² / 1.5 MVA = 8.832 mΩ at X/R 6 (R 1.452, X 8.712 mΩ). Running 150/(0.95·0.88) = 179.4 kVA, starting 6 × = 1076.6 kVA → Zm = 480²/1076.6 kVA = 0.21401 Ω at PF 0.3 (R 64.20, X 204.15 mΩ). V = |Zm|/|Zt + Zm| = 0.21401/0.22276 = 0.9607 → dip 3.93 %; torque ≈ 0.9607² = 92.3 % of locked-rotor.
| Quantity | Expected | RokBench | Error | Result |
|---|---|---|---|---|
| startingKva | 1076.6 | 1076.6 | 0% | Pass |
| busDuringPercent | 96.07 | 96.07 | 0% | Pass |
| busDipPercent | 3.93 | 3.93 | 0% | Pass |
| torquePercentOfLocked | 92.3 | 92.3 | 0% | Pass |
Electrical room: switchboards, panelboards, 75 kVA dry-type transformer, 100 kVA UPS room/heat · Hand calculation
PassSource: Hand calculation from the published loss equations; transformer efficiency 98.60% at 35% load from 10 CFR 431.196 (three-phase LV dry-type, 75 kVA) — Switchboards 0.6·2000·0.8²·2 = 1536 W; panelboards 0.4·225·0.64·4 = 230.4 W; transformer Pt = 75000·0.35·(1/0.986 − 1) = 372.7 W → 186.4 + 1521.3·0.64 = 1160.0 W; UPS 100·0.9·0.8·1000·(1/0.95 − 1) = 3789.5 W. (6715.9 + 500)·1.1 = 7937 W = 27,084 BTU/hr = 2.26 tons.
| Quantity | Expected | RokBench | Error | Result |
|---|---|---|---|---|
| equipmentW | 6716 | 6716 | 0% | Pass |
| totalW | 7937 | 7937 | 0% | Pass |
| btuPerHr | 27084 | 27084 | 0% | Pass |
| tons | 2.26 | 2.26 | 0% | Pass |
480 V bus behind 1500 kVA, 5.75 % Z, X/R 6 — ANSI and IEC shortcircuit/duty · Hand calculation
PassSource: Hand calculation from the ANSI (IEEE C37.13 practice) and IEC 60909-0 equations on the Methods page — Zt = 0.0575 · 480² / 1.5 MVA = 8.832 mΩ. ANSI: I = 480/(√3·Zt) = 31.38 kA; asym = I·√(1+2e^(−2π/6)) = 40.93 kA; peak = √2·I·(1+e^(−π/6)) = 70.66 kA; MCCB MF = 1.3046/1.2469 = 1.046. IEC: c = 1.05; xT = 0.0567; KT = 0.95·1.05/(1+0.6·0.0567) = 0.9647; Ik″ = 1.05·480/(√3·KT·Zt) = 34.15 kA; κ = 1.02+0.98e^(−0.5) = 1.614; ip = κ·√2·Ik″ = 77.98 kA.
| Quantity | Expected | RokBench | Error | Result |
|---|---|---|---|---|
| ansi.firstCycleKa | 31.38 | 31.38 | 0% | Pass |
| ansi.asymRmsKa | 40.93 | 40.93 | 0% | Pass |
| ansi.peakKa | 70.66 | 70.66 | 0% | Pass |
| ansi.multiplyingFactor | 1.046 | 1.046 | 0% | Pass |
| iec.kt | 0.9647 | 0.9647 | 0% | Pass |
| iec.ikssKa | 34.15 | 34.15 | 0% | Pass |
| iec.kappa | 1.614 | 1.614 | 0% | Pass |
| iec.ipKa | 77.98 | 77.98 | 0% | Pass |
Fixed-tilt array, 500 kWdc at 35° latitude, 30° tilt solar/pv · Hand calculation
PassSource: Hand calculation from the solar position equations (declination −23.45°, hour angle 15°/h) and row-shadow geometry — 09:00 solar time on the winter solstice: α = 17.646°, γ = 42.901°. Pitch = 2cos30° + 2sin30°·cos42.901°/tan17.646° = 4.0349 m; GCR = 2/4.0349 = 0.4957; land = 1250 · 2 / 0.4957 = 5043.6 m². Energy = 500 · 5.5 · 365 · 0.8 = 803,000 kWh.
| Quantity | Expected | RokBench | Error | Result |
|---|---|---|---|---|
| modules | 1250 | 1250 | 0% | Pass |
| pitchM | 4.0349 | 4.035 | 0.002% | Pass |
| gcr | 0.4957 | 0.496 | 0.061% | Pass |
| landAreaM2 | 5043.6 | 5043.6 | 0% | Pass |
| annualKwh | 803000 | 803000 | 0% | Pass |
Engine 0.48.0. Cases live in the repository under validation/ and run in CI. Corrections are logged in the Engineering Notes. Have a published example we should add? Use the Feedback link.