1. What is Maximum Demand Calculation?

Maximum Demand (MD) calculation is a method used in electrical engineering to determine the maximum expected load on an electrical installation. The formula MD = Largest Circuit + 40% of Remaining Circuits is commonly used for wiring design to ensure proper sizing of conductors and protection devices.

2. How Does the Calculator Work?

The calculator uses the maximum demand formula:

Where:

• Largest Circuit — The circuit with the highest amperage rating
• Remaining Circuits — All other circuits in the installation
• 0.4 — The diversity factor (40%) applied to remaining circuits

Explanation: This calculation accounts for the fact that not all circuits will be operating at full capacity simultaneously, applying a diversity factor to the non-dominant circuits.

3. Importance of Maximum Demand Calculation

Details: Accurate maximum demand calculation is essential for proper electrical system design, ensuring conductors, protection devices, and transformers are appropriately sized for the expected load while maintaining safety margins.

4. Using the Calculator

Tips: Enter all circuit amperage values separated by commas. The calculator will automatically identify the largest circuit and apply the 40% diversity factor to the sum of remaining circuits.

5. Frequently Asked Questions (FAQ)

Q1: Why use 40% for remaining circuits?
A: The 40% diversity factor accounts for the statistical probability that not all circuits will be operating at maximum capacity simultaneously, based on typical usage patterns.

Q2: When should this calculation be used?
A: This calculation is typically used for residential and small commercial electrical installations to determine appropriate conductor sizing and protection device ratings.

Q3: Are there different diversity factors for different applications?
A: Yes, diversity factors can vary based on the type of installation, number of circuits, and specific electrical codes applicable in different regions.

Q4: What if I have motor circuits or other special loads?
A: Special loads like motors may require additional considerations such as starting currents. Consult relevant electrical codes for specific requirements.

Q5: How does this affect main breaker sizing?
A: The calculated maximum demand helps determine the appropriate rating for the main circuit breaker, ensuring it can handle peak loads without nuisance tripping.