About the Electrical Load Calculator

The Electrical Load Calculator (Building) is a professional tool designed for electrical engineers, architects, contractors, and builders to estimate total electrical load for residential and commercial buildings. It calculates power consumption, current requirements, recommended breaker sizes, and cable specifications based on connected appliances and equipment.

⚡Key Features

•Dynamic appliance table with unlimited rows
•Pre-built appliance templates for quick entry
•Real-time load calculation
•Breaker and cable size recommendations
•Export to TXT and CSV formats

🎯Use Cases

•Electrical system design and planning
•Circuit breaker sizing
•Cable specification selection
•Building permit applications
•Energy consumption estimation

How to Use the Calculator

1.Configure Settings: Select voltage (110V or 220V), load type, and demand factor
2.Add Appliances: Enter appliance details or use quick templates
3.Input Details: Specify quantity, power rating, and category for each appliance
4.Review Results: See total load, current, breaker size, and cable recommendations
5.Export Data: Download results as TXT or CSV for documentation

Understanding the Calculations

Step 1: Calculate Total Connected Load

Total Load (W) = Σ (Quantity × Power Rating)

Sum the power consumption of all appliances considering their quantities.

Step 2: Apply Demand Factor

Demand Load (kW) = Total Load × Demand Factor

Apply diversity factor since not all appliances run simultaneously.

Step 3: Calculate Current

Current (A) = (Demand Load × 1000) / (Voltage × Power Factor)

Calculate the current draw based on voltage and power factor.

Step 4: Size Breaker

Breaker Size = Current × 1.25 (rounded up to standard size)

Add 25% safety margin and round to nearest standard breaker rating.

Example Calculation

Appliances:

• 3 Fans @ 75W = 225W

• 5 Lights @ 15W = 75W

• 1 AC @ 1500W = 1500W

Total: 1800W = 1.8 kW

Demand (80%): 1.44 kW

Current: (1440W) / (220V × 0.8) = 8.18 A

Breaker: 8.18 × 1.25 = 10.23 A → 16A breaker

Demand Factor Guidelines

100% - No Diversity

All loads running simultaneously (worst case)

100%

90% - Low Diversity

Critical facilities, data centers

90%

80% - Recommended

Typical residential and commercial buildings

80%

70% - High Diversity

Large buildings with varied usage patterns

70%

Standard Breaker Sizes

Common Breaker Ratings (Amps):

6A10A16A20A25A32A40A50A63A80A100A125A160A200A

Cable Size Reference

Current (A)	Cable Size (mm²)	Typical Use
Up to 6A	1.5 mm²	Lighting circuits
Up to 10A	2.5 mm²	Power outlets
Up to 16A	4 mm²	Heavy appliances
Up to 20A	6 mm²	Air conditioners
Up to 32A	16 mm²	Main distribution

Practical Applications

New Construction

Calculate total electrical load during design phase to properly size main service panel, feeders, and branch circuits.

Renovations

Assess existing capacity and determine if service upgrade is needed when adding new appliances or equipment.

Safety Planning

Prevent circuit overload by ensuring breakers and cables are properly sized for the connected load.

Cost Estimation

Estimate material costs for electrical installation by determining required breaker and cable specifications.

Why Use This Calculator?

✓Instant Results: Real-time calculation as you add appliances
✓Quick Templates: Pre-built appliance library for fast data entry
✓Professional Output: Export detailed reports in TXT or CSV format
✓Safety Recommendations: Automatic breaker and cable sizing with safety margins
✓Free & Accessible: No registration required, works entirely in your browser

⚠️Important Safety Note

This calculator provides estimates for planning purposes. Always consult with a licensed electrician and follow local electrical codes and regulations. Electrical work should only be performed by qualified professionals. The recommendations provided are general guidelines and may need adjustment based on specific installation conditions, cable routing, ambient temperature, and local code requirements.

Electrical Load Calculator (Building)