Calculate circuit load, breaker size, and wire sizing. Perfect for DIY projects and planning.

⚡ Enter Circuit Parameters:

Voltage (V)

Volts

Phase Type

Load Power (W)

Watts

Power Factor

Resistive: 1.0 | Motors: 0.8 | Electronics: 0.95

Wire Length (optional)

For voltage drop calculation (round-trip distance)

⚡ Electrical Safety & Standards

Formulas:

• Single-phase: I = P ÷ (V × PF)
• Three-phase: I = P ÷ (√3 × V × PF)
• Voltage drop: Vdrop = 2 × L × I × R

⚠️ Safety First!

• Always consult licensed electricians
• Follow NEC/IEC/BS 7671 codes
• Use proper circuit protection

Breaker Sizing

• Continuous loads: 125% rule
• Non-continuous: 100% rule
• Match wire ampacity

Pro Tips

• Calculate round-trip distance
• Factor in ambient temperature
• Consider future expansion
• Include derating factors

📋 Common Wire Sizes & Ampacities:

AWG	mm²	Max Ampacity*	Typical Use
14	2.08	15A	Lighting circuits
12	3.31	20A	General outlets
10	5.26	30A	Dryers, water heaters
8	8.37	40A	Ranges, HVAC
6	13.3	55A	Electric vehicle

* For 75°C copper wire in free air. Actual values vary by installation.

Disclaimer:

This tool provides educational estimates only. Always consult with a qualified electrician and follow local electrical codes for actual installations.

🔌 Circuit Calculator