Free Engineering Tool

Cable Size Calculator

Calculate the correct cable cross-section (mm²) for any electrical load — based on IS 1554 / IS 732 standards.

Enter Load Details

System Type

Load (kW)

Voltage (V)

Cable Length (m)

Power Factor

Conductor

Installation

Allowable Voltage Drop (%)

⚡

Enter load, voltage and cable length to get your result.

Formula Used

I = P / (√3 × V × PF) ← 3-phase FLC

I = P / (V × PF) ← 1-phase FLC

A = (√3 × L × I × ρ) / ΔV ← VD sizing

ρ(Cu) = 0.0175 Ω·mm²/m | ρ(Al) = 0.028 Ω·mm²/m

IS 1554 Current Carrying Capacity Reference

Ampere ratings at 30°C ambient, 90°C conductor temperature

Size (mm²)	Cu Underground	Al Underground	Cu In Air	Al In Air
1.5 mm²	27 A	21 A	18 A	14 A
2.5 mm²	36 A	28 A	25 A	19 A
4 mm²	48 A	37 A	33 A	26 A
6 mm²	62 A	48 A	43 A	33 A
10 mm²	85 A	65 A	58 A	45 A
16 mm²	112 A	87 A	78 A	60 A
25 mm²	141 A	109 A	100 A	77 A
35 mm²	173 A	133 A	122 A	94 A
50 mm²	210 A	162 A	149 A	115 A
70 mm²	258 A	199 A	189 A	146 A
95 mm²	310 A	239 A	229 A	177 A
120 mm²	358 A	276 A	263 A	203 A
150 mm²	407 A	314 A	302 A	233 A
185 mm²	464 A	358 A	345 A	266 A
240 mm²	541 A	416 A	407 A	314 A
300 mm²	621 A	479 A	468 A	361 A

Disclaimer: This calculator provides indicative cable sizing based on IS 1554 and IS 732 standards under standard conditions. Results must be verified by a licensed electrical engineer before use in actual installations. Derating factors for ambient temperature, grouping, and soil thermal resistivity may apply. KVP Electricals Pvt Ltd accepts no liability for decisions made solely on the basis of this tool.

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