// FREE CALCULATORS

Electrical Engineering
Calculators

Free, browser-based tools for quick calculations — NEC and IEC methods, no download required. For full workflow automation, see the Tools & Products page.

CABLE AMPACITY

Cable Ampacity Derating

NEC Table 310.16 base ampacity with temperature correction and grouping factors. IEC 60364-5-52 reference.

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CABLE TRAY FILL

Cable Tray Fill Calculator

Area-fill method for ladder/ventilated trough (50%) and solid-bottom tray (40%) per NEC Article 392. Instant pass/fail.

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CONDUIT FILL

Conduit Fill Calculator

NEC Chapter 9 Table 1 fill limits. EMT, IMC, RMC, PVC, HDPE. Instant pass/fail and upsize recommendations.

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DEMAND LOAD

Demand Load Calculator

Add load groups with individual demand factors. Apply diversity factor and design margin. Outputs kW and kVA for equipment sizing.

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DUCT BANK SIZING

Duct Bank Sizing Calculator

Envelope dimensions, concrete volume, and burial depth reference from conduit rows/columns and spacing. NEC and IEC.

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GROUND GRID

Ground Grid Resistance Calculator

Grid resistance, ground potential rise, and touch/step voltage screening check — IEEE 80 simplified method.

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MOTOR POWER

Motor Power Calculator

Rated Output or Absorbed Load input mode. Full load current, LRA, kW/kVAR/kVA. NEC Art. 430 and IEC 60034.

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SHORT CIRCUIT

Short Circuit Current (MVA Method)

Three-phase, line-to-line, and line-to-ground fault currents at transformer secondary or end of cable run.

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VOLTAGE DROP

Voltage Drop Calculator

Single-phase and three-phase. Equipment rating → derived current. NEC Art. 210/215 and IEC 60364-5-52. Max length outputs.

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Disclaimer: These calculators are provided for reference and preliminary estimation only. Results should be verified by a qualified engineer against the applicable code, project specification, and equipment data before use in design, procurement, or construction documents.