1. What is Maximum Demand Calculation?

Maximum Demand (MD) calculation is a method used in electrical installations to determine the maximum expected load. The UK standard method uses the formula: MD = Largest Circuit + 40% of Remaining Circuits.

2. How Does the Calculator Work?

The calculator uses the standard UK maximum demand formula:

Where:

• \( C_{\text{max}} \) — The largest circuit load (Amps)
• \( \sum_{i=1}^{n-1} C_i \) — Sum of all remaining circuit loads
• 0.4 — 40% diversity factor for remaining circuits

Explanation: This calculation assumes that while the largest circuit may be fully loaded, only 40% of the remaining circuits will be simultaneously active.

3. Importance of Maximum Demand Calculation

Details: Accurate maximum demand calculation is crucial for proper sizing of electrical cables, protective devices, and distribution equipment to ensure safety and prevent overload conditions.

4. Using the Calculator

Tips: Enter all circuit loads in Amps, separated by commas. The calculator will automatically identify the largest circuit and apply the 40% diversity factor to the remaining circuits.

5. Frequently Asked Questions (FAQ)

Q1: Why use 40% for remaining circuits?
A: The 40% factor is based on statistical analysis showing that not all circuits operate at full capacity simultaneously in typical installations.

Q2: Is this calculation method applicable to all installations?
A: This is a standard method but specific installations may require different diversity factors based on actual usage patterns.

Q3: What units should I use for circuit loads?
A: All circuit loads should be entered in Amperes (A) for consistent calculation.

Q4: How does this affect cable sizing?
A: The calculated maximum demand determines the current-carrying capacity required for main cables and protective devices.

Q5: Are there exceptions to this calculation method?
A: Special installations like industrial processes or buildings with unusual load patterns may require different calculation methods.