AC Cable Size Calculator Single & Three Phase

Calculate cable size based on load, voltage, length, material & installation

⚡ Load (kW)

⚡ System Voltage

🔌 Phase Type

⚡ Power Factor (cos φ)

📏 Cable Length (metres)

🔧 Cable Material

📐 Installation Type

🌡️ Cable Insulation Temp (°C)

📖 AC Cable Size Calculator

This AC cable size calculator helps you determine the correct cable size for single-phase and three-phase AC electrical systems. It considers load (kW), voltage, cable length, material (copper/aluminum), power factor, and installation method.

📐 Cable Sizing Formula

Single Phase: I = P × 1000 / (V × PF)
Three Phase: I = P × 1000 / (√3 × V × PF)
Voltage Drop: VD = (mV/A/m × I × L) / 1000
VD% = (VD ÷ V) × 100 ≤ 3% (lighting) or 5% (power)

📊 Standard Cable Sizes (mm²)

Size (mm²)	Copper (A)	Aluminum (A)	Common Use
1.0	11-15	8-12	Lighting
1.5	14-19	10-14	Lighting, Small loads
2.5	20-27	15-20	Socket circuits
4	30-37	22-28	Cookers, Showers
6	38-47	29-36	Large loads
10	52-65	40-50	Sub-mains
16	69-87	55-70	Sub-mains
25	90-115	75-95	Main tails
35	115-145	95-120	Main supplies
50	140-180	115-150	Large supplies

❓ Frequently Asked Questions

What cable size do I need for 10kW? ▼

For 10kW three-phase at 400V with PF 0.85: Current = 10,000 / (√3 × 400 × 0.85) = 17A. For 50m run, 4mm² copper cable is typically recommended.

Copper vs Aluminum cable? ▼

Copper has higher conductivity (carries more current for same size) and is more durable. Aluminum is cheaper and lighter but requires larger cable sizes for the same current.

What is voltage drop? ▼

Voltage drop is the reduction in voltage along the cable. In AC systems, voltage drop should not exceed 3% for lighting and 5% for power circuits.

Single phase vs three phase? ▼

Single phase uses 2 wires (live + neutral) at 230V. Three phase uses 4 wires (3 live + neutral) at 400V. For the same power, three phase current is √3 times lower.