Calculator Inputs
Example Data Table
| Case | System | Voltage | Current | Length | Area | Material | Approx. Loss | Approx. Drop |
|---|---|---|---|---|---|---|---|---|
| Workshop Pump Feed | Single-Phase AC | 230 V | 25 A | 40 m | 10 mm² | Copper | 21.6 W | 0.86 V |
| Factory Motor Run | Three-Phase AC | 415 V | 60 A | 75 m | 35 mm² | Aluminum | 261.7 W | 2.51 V |
| Battery Charger Line | DC | 120 V | 15 A | 20 m | 4 mm² | Copper | 38.8 W | 2.59 V |
These rows are illustrative sample cases for quick comparison.
Formula Used
1) Current from load power
DC: I = P / V
Single-phase AC: I = P / (V × pf)
Three-phase AC: I = P / (√3 × V × pf)
2) Temperature-corrected resistivity
ρT = ρ20 × [1 + α(T − 20)]
3) Resistance from material and geometry
Base relation: R = ρL / A
DC and single-phase: total loop length = 2 × one-way length
Three-phase: per-phase conductor resistance uses one-way length
4) Power loss
DC and single-phase: Ploss = I²R
Three-phase balanced: Ploss = 3I²R
5) Voltage drop
DC and single-phase: Vdrop = IR
Three-phase balanced: Vdrop = √3 × I × R
6) Efficiency and energy loss
Efficiency: η = Useful Power / (Useful Power + Loss Power)
Energy loss: kWh lost = (Ploss / 1000) × operating hours
This tool focuses on resistive conductor loss. It does not model reactance, harmonics, skin effect, or complex network behavior.
How to Use This Calculator
- Select the system type: DC, single-phase AC, or three-phase AC.
- Choose whether you will enter current directly or let the tool derive current from load power.
- Pick a resistance method. Use direct resistance when you already know conductor resistance. Use material mode when you know length, area, and material.
- Enter temperature, parallel runs, operating hours, and energy rate for more complete results.
- Press the calculate button. The results card will appear above the form with voltage drop, power loss, efficiency, cost impact, chart, and export options.
FAQs
1) What systems does this calculator support?
It supports DC, single-phase AC, and balanced three-phase AC circuits. That makes it useful for feeders, branch circuits, battery links, and many motor supply runs.
2) When should I use direct resistance mode?
Use direct mode when cable test data, datasheets, or previous calculations already give you conductor resistance. It is faster when geometry details are unavailable.
3) Why does temperature change the answer?
Most conductor materials increase in resistance as temperature rises. Higher resistance causes larger voltage drop and higher I²R losses for the same current.
4) Why is the three-phase loss formula different?
A balanced three-phase system has three energized conductors sharing load current. Total conductor loss is the sum of each phase loss, which becomes 3I²R.
5) Does this include reactance or harmonics?
No. This page estimates resistive losses and resistive voltage drop only. It does not model cable reactance, harmonic distortion, skin effect, or transient behavior.
6) What are parallel runs?
Parallel runs mean two or more identical conductors share the same current path. More parallel runs lower effective resistance and reduce heating and drop.
7) How is annual loss cost estimated?
The tool converts power loss into daily, monthly, and annual energy loss using operating hours. It then multiplies annual lost kilowatt-hours by your energy rate.
8) Can I use this for cable sizing decisions?
Yes, it is useful for early comparisons. Still, final cable sizing should also consider ampacity, insulation limits, installation method, fault duty, and code requirements.