MachineCalcs

Electrical Calculators

Check feeder, source and raceway work: voltage drop, ampacity derating, parallel conductor ampacity, motor full-load amps, motor overload heater/dial settings, equipment grounding conductor size formula screens, transformer kVA chart sizing, available fault current from transformer/source/downstream impedance, off-grid source sizing, PV string/MPPT voltage windows, access-control power, conduit fill, box fill, conduit bend offsets and pull tension with sidewall-pressure screening.

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Voltage drop wire size Voltage drop, percent drop and suggested conductor area from run length and load. Voltage drop by transformer kVA Derive load current from kVA, voltage and phase before checking feeder drop. Transformer kVA chart Load kVA, design margin, standard-size round-up and full-load current. Available fault current Transformer secondary short-circuit current from kVA, percent impedance, X/R and optional downstream impedance. Off-grid solar worksheet PV watts, battery amp-hours, autonomy days, controller current and inverter size. Solar string sizing Cold Voc, hot Vmp, MPPT window, max DC voltage and parallel-string current. Conduit fill worksheet Mixed conductor rows, raceway area, fill limit and remaining area. Conduit bend offset Worksheet for offset multiplier, bend marks, shrink and bend budget. Motor full-load amps Formula FLA from horsepower or kW, voltage, phase, efficiency and power factor. Box fill calculation NEC-style device box fill from conductors, devices, grounds and clamps. Motor overload heater chart Relay/heater target from nameplate FLA and entered multiplier. Grounding conductor size formula Equipment grounding conductor screen from upstream OCPD rating. Parallel conductor ampacity Total entered per-conductor ampacity across parallel paths after derating, terminal cap and sharing allowance.

Workflow suites using Electrical

Multi-tool paths for jobs that cross category boundaries.

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3 linked Fluid Power Manufacturing Size hydraulic and pneumatic actuators, pumps, receivers and hose runs, then screen drive motor amps, overloads and dosing rates for the same line.

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Voltage Drop Voltage drop, percent drop, load-end voltage and suggested conductor area from phase, wire size, current or transformer kVA and one-way length. Ampacity Derating Adjusted conductor ampacity from base ampacity, ambient correction, conductor-count adjustment, terminal cap and load multiplier. Parallel Conductor Ampacity Total usable ampacity for parallel conductors from user-entered per-conductor ampacity, derating factors, terminal cap and current-sharing allowance. Feeder Conductor Size Two-path conductor check: 125% continuous + noncontinuous at terminations, and corrected ampacity vs load after derating. Dwelling Service Load NEC 220.82 optional-method structure: 100%/40% general demand plus the largest heating/cooling option, amps and next standard size. Access Control Power Supply Low-voltage access-control supply amperage, wire voltage drop, recommended AWG and standby battery amp-hours from lock, reader, accessory and panel currents. Transformer kVA Single-phase or three-phase transformer kVA from volts and amps or kW and power factor, with standard-size chart rounding. Short-Circuit Current Transformer secondary short-circuit current and available fault current from kVA, impedance percent, X/R ratio, optional source and downstream impedance. Motor Full-Load Amps Formula motor full-load amps from horsepower or kW, voltage, phase, efficiency and power factor, with design-current and service-factor checks. Motor Inrush Current Locked-rotor amps from the nameplate code letter (NEC 430.7(B) kVA/hp bands), single or three phase, with the times-FLA multiple. Transformer Secondary Conductor NEC 240.21(C) rule paths (10 ft, 25 ft, industrial, outside, primary-protected): required ampacity with the governing rule named — table-free. Motor Feeder Sizing NEC 430.24 feeder ampacity for several motors (125% largest + the rest + non-motor loads) and the 430.62(A) max OCPD — table-free. Motor Overload Size Motor overload relay or heater target setting from nameplate FLA, entered multiplier, selected setting and running-current margin. Grounding Conductor Size Equipment grounding conductor size from upstream OCPD rating, copper/aluminum material, selected EGC size and voltage-drop upsizing ratio. Off-Grid Solar Off-grid PV array watts, battery bank amp-hours, installed battery kWh, charge-controller current and inverter size from daily load and peak sun hours. Solar String Sizing PV modules in series/parallel from module Voc/Vmp temperature coefficients, inverter MPPT window, max DC voltage and input current. Conduit Fill Raceway fill worksheet from conductor count, insulation area and conduit trade size, with NEC-style 53/31/40/60% limits. Electrical Box Fill Outlet, switch and junction box fill from conductor counts, AWG volume allowances, device yokes, grounds, clamps and support fittings. Conduit Bend Offset Two-bend conduit offset layout worksheet from offset height and bend angle, with multiplier, mark spacing, shrink, run margin and bend budget. Conduit Pull Tension Wire or cable pull tension, capstan bend multiplier, sidewall pressure and utilization from route length, friction, bend angle and manufacturer limits.

This Electrical cluster covers the early feeder, raceway and low-voltage checks that usually happen before a panel, cabinet or equipment layout is final. The voltage drop calculator screens copper or aluminum conductors with the circular-mil shortcut VD = M×K×I×L/CM, where M is 2 for single-phase/DC or √3 for balanced three-phase. It reports volts lost, percent drop, load-end voltage, maximum one-way length and the first listed conductor area that meets your target drop. The ampacity derating calculator then applies user-entered ambient correction, current-carrying conductor adjustment and project derating factors to a base ampacity, compares the usable ampacity with a multiplied design load, and keeps terminal/equipment ampacity caps visible for branch or feeder screens. The parallel conductor ampacity calculator uses the entered per-conductor ampacity, the same derating-factor stack, terminal cap, current-sharing allowance and number of same-phase parallel paths to report total usable ampacity, per-path current, utilization and margin. These ampacity screens do not choose the governing code table for you; they audit the entered values and derates. For motor loads, the motor full-load amps calculator estimates formula running current from output power, voltage, efficiency and power factor, then reports design current, service-factor current and selected-current utilization without pretending to be a code table. The motor overload size calculator keeps the protection step explicit by multiplying nameplate FLA by a user-entered overload multiplier, showing the heater/dial chart workflow, comparing the selected relay or heater setting and reporting running-current headroom. The grounding conductor size calculator covers the equipment-grounding side: upstream OCPD rating, copper or aluminum EGC material, selected wire size, optional voltage-drop upsizing ratio and parallel-raceway count.

For low-voltage door hardware, the access control power supply calculator turns lock, reader, REX/accessory and controller current draws into total active load, design supply amperage, the next listed DC supply size, farthest-run voltage drop, recommended copper AWG and standby battery amp-hours. It is built for the access-control planning workflow where 12 V versus 24 V, maglock simultaneity and backup runtime matter before hardware is ordered.

For source capacity, the transformer kVA calculator uses kVA = V×I/1000 for single phase, kVA = √3×V_LL×I/1000 for three phase, or kVA = kW/PF when real power is known. It applies a sizing margin, uses a transformer kVA chart to round up to a common standard rating, and reports full-load current, utilization and spare capacity. The short-circuit current calculator starts from transformer kVA, voltage, percent impedance and X/R ratio, then adds optional source and downstream R/X impedance to estimate available fault current and interrupt-rating utilization. For standalone cabins, sheds, gates or remote equipment, the off-grid solar calculator turns daily kWh, peak sun hours, inverter efficiency, autonomy days and battery voltage into PV array watts, battery bank amp-hours, installed battery kWh, charge-controller current and inverter continuous/surge sizing. The solar string sizing calculator checks module Voc/Vmp temperature coefficients, cold and hot design temperatures, inverter max DC voltage, MPPT start/min/max voltage, input current and DC:AC ratio so PV series/parallel strings stay inside the entered datasheet window.

The conduit fill calculator then screens the raceway by summing conductor insulation areas and comparing the total with usable conduit area. It applies common NEC-style Chapter 9 fill percentages: 53% for one conductor, 31% for two, 40% for three or more, and 60% for short nipples when that condition applies. The electrical box fill calculator checks outlet, switch and junction box volume from conductor counts, #18 through #6 AWG volume allowances, equipment grounds, device yokes, internal clamps and support fittings. The conduit bend offset calculator covers layout: offset multiplier, distance between bend marks, shrink allowance, projected run and remaining 360-degree bend budget. The conduit pull tension calculator adds the pull-risk screen with cable weight, route length, friction coefficient, total bend angle, bend radius, final pulling tension, sidewall pressure and entered manufacturer limits. These tools are design and estimating screens only; final work still needs the adopted code edition, local amendments, motor nameplate data, overload relay/heater manufacturer instructions, conductor ampacity table selection, ampacity adjustment/correction factors, parallel conductor rules, PV module and inverter datasheets, PV string voltage/current limits, rapid shutdown, available fault-current study data, interrupting ratings/SCCR, box fill, bend radius, pulling tension, overcurrent protection, equipment grounding, listed low-voltage equipment instructions and the exact manufacturer dimensions.

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