Ampacity Calculator — Calculate Wire Current Capacity

Ampacity Calculator

Calculate the ampacity (current-carrying capacity) of electrical wires. Determine safe current limits based on wire size, insulation type, and installation conditions.

Step 1: Wire Specifications

Understanding Ampacity

Ampacity is the maximum current a wire can carry without exceeding its temperature rating. It depends on wire size, material, insulation type, and installation conditions.

Step 2: Environmental Factors

30°C
3

Temperature & Derating Factors

Higher ambient temperatures reduce ampacity. Multiple conductors in close proximity also require derating due to reduced heat dissipation.

Ampacity Calculation Results

Summary
Wire Comparison
Breakdown

Maximum Safe Current

30A
Based on 10 AWG copper wire with 90°C insulation
Base Ampacity
35A
Temperature Derating
0.94
Conductor Derating
0.90
Safety Margin
15%

Wire Size Comparison

Wire Size Copper Ampacity Aluminum Ampacity Voltage Drop/100ft

Ampacity Derating Factors

Ampacity Formula

Adjusted Ampacity = Base Ampacity × Temperature Factor × Conductor Factor × Safety Factor

Base ampacity depends on wire size and material. Temperature and conductor count factors are applied based on NEC tables. Always consult local electrical codes for final values.

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