kW to Cable Size Calculator

How to Use the kW to Cable Size Calculator

1. Enter your load power in kW.
2. Select System Type (voltage + single/three-phase).
3. Enter Power Factor (PF) and cable length.
4. Choose the Voltage Drop Limit (%) and Installation Method.
5. Set the Ambient Temperature. Results update automatically.

What This Tool Calculates

• Load current (A) from kW, voltage and PF
• Cable size recommendation using a practical ampacity table (mm² + AWG label)
• Voltage drop (%) from current, length and cable resistance
• Safety margin (%) showing how much ampacity remains above the load

Formulas Used

3-Phase Current

I = (kW × 1000) / (√3 × V × PF)

Single-Phase Current

I = (kW × 1000) / (V × PF)

Voltage Drop (Quick Check)

3Φ: Vd = (√3 × I × L × R) / 1000

1Φ: Vd = (2 × I × L × R) / 1000

FAQ

Why does the cable size change with installation method?

Different installation environments affect heat dissipation. This tool applies a practical installation factor for quick sizing.

Why is PF required?

Because kW is real power. Lower PF means higher current for the same kW, which increases cable size requirement.

Is the voltage drop calculation exact?

It’s a fast check using typical copper resistance values. For final design, verify using your project standard and manufacturer data.

About This Tool

MEPBase kW to Cable Size Calculator is designed for fast, practical sizing during concept, shop drawing, and estimation stages. It’s especially useful for quick checks for motors, lighting feeders, panels, and equipment connections.