Wire Calculators

Choosing the right wire gauge is critical for safety and voltage stability. The Wire Size Calculator computes recommended conductor size (AWG or mm²) based on load current, circuit length, system voltage and acceptable voltage drop. It helps prevent overheating, saves on copper cost, and ensures equipment receives adequate voltage. Ideal for electricians, solar installers and DIYers, the tool also suggests conduit and insulation notes for practical installation.

Definition / Why it matters

Wire gauge affects voltage drop and thermal capacity. Long runs or high currents need larger conductors to keep voltage within acceptable limits and avoid excessive losses.

Formula(s)

• Voltage drop (Vdrop) = I × R × 2 × length (for 2-way)

• R (resistance per meter) depends on conductor size & material

• Required conductor area from allowed voltage drop: A ≈ (2 × ρ × I × L) / (Vdrop_allowed) — practical table mapping used.

(Implement standard AWG/mm² lookup rather than raw formula for accuracy.)

Inputs (UI)

• Load current (A) or load power + voltage (W & V)

• One-way length (m)

• System voltage (V)

• Acceptable voltage drop (%) (default 3% or 5%)

• Conductor material (copper/aluminum)

• Single-phase/three-phase toggle (affects factor)

How to use

1. Enter current and length. 2. Choose voltage & allowed drop. 3. Calculate → recommended AWG/mm² and expected Vdrop. 4. Show nearest standard conductor size and brief installation note.

Examples (5)

• 20 A, 30 m, 230 V, 3% → recommended 2.5 mm² (example)

• 50 A, 10 m, 400 V, 3% → recommended 16 mm²

Quick table (sample)

FAQs (6)

• What voltage drop is acceptable? (3% for branch circuits, 5% total)

• Why choose copper over aluminum? (conductivity & ampacity)

• How to calculate for three-phase? (use √3 factor)

• Can I use multiple smaller conductors in parallel? (yes but follow code)

• Do insulation and temperature affect sizing? (yes)