Electrical calculators

Enter a straight-bend-straight-bend-straight conduit route to compare the pull from each end. The calculator reports the lower-utilization direction, section tensions, sidewall pressure, and headroom against your entered limits.

Enter one cable outside diameter, cable count, raceway type, and trade size. The calculator checks fill, three-cable clearance, and the IEEE 1185 jam-ratio avoidance range so a raceway that passes fill is not treated as automatically pullable.

Enter the copper AWG size and a resistance reading to estimate how much cable is on a reel. The calculation subtracts test-lead resistance, corrects copper resistance for temperature, and reports a likely range.

Enter the CT ratio, excitation-curve points, secondary circuit burden, fault current, X/R ratio, and remanence. The calculator estimates first-cycle composite error, time to a 10% peak-current error, and the primary fault current that reaches that reference.

Enter the usage, billed peak demand, rates, and billing days from a commercial electric bill. The calculator separates energy and demand charges, then estimates the savings from reducing the peak kW.

Enter the source, transformer, feeder, and locked-rotor motor data to estimate the starting voltage at the motor terminals. The calculator also reverse-solves the one-way feeder length that reaches your selected minimum starting voltage.

Enter the three line-to-line voltages measured at a running motor, then compare the actual load with the NEMA MG 1 voltage-unbalance derating curve. The result shows whether the motor is in the normal range, needs derating, is overloaded after derating, or is outside the encoded curve.

Measure a ringing frequency before and after adding a known test capacitor to estimate the loop parasitics. The calculator turns that estimate into a starting RC pair, nearby resistor values to test, and first-pass electrical stress figures.

Enter the vertical rise and sideways roll to turn them into one true offset. The result gives the bender clocking angle, mark spacing, shrink, and adjusted subtract-shrink reference for two equal bends.

Enter the three line-to-line voltage readings to calculate percent voltage unbalance, compare it with a NEMA-style limit, and estimate motor derating. The tool also solves the acceptable range for one selected third voltage while the other two readings stay fixed.

Enter the transformer, upstream source, feeder, and device rating. The calculator estimates symmetrical bolted-fault current at the transformer secondary and at the feeder end, then checks the entered interrupting rating.

Enter the three fundamental phase currents, the per-phase triplen harmonic percentages, and the adjusted neutral ampacity. The calculator reports true-RMS neutral current, harmonic contribution, largest phase true-RMS current, and whether the entered neutral ampacity is exceeded.

Enter the measured UPS load and battery-bank details to estimate available runtime, then reserve enough of it for an orderly shutdown. The calculation accounts for battery condition, usable discharge depth, inverter losses, idle draw, and the higher-current penalty described by Peukert’s law.