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MD = Largest Circuit + 40% of Remaining Circuits
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Maximum Demand (MD) calculation for residential electrical installations determines the highest expected electrical load. It helps in proper sizing of electrical service equipment, circuit breakers, and wiring to ensure safe and efficient operation.
The calculator uses the standard formula:
Where:
Explanation: This formula accounts for the fact that not all electrical circuits operate at full capacity simultaneously in a residential setting.
Details: Accurate maximum demand calculation is essential for proper electrical system design, preventing circuit overloads, ensuring code compliance, and optimizing energy efficiency in residential buildings.
Tips: Enter all circuit loads in Amperes (A), separated by commas. The calculator will automatically identify the largest circuit and apply the 40% diversity factor to the remaining circuits.
Q1: Why use 40% for remaining circuits?
A: The 40% diversity factor accounts for the statistical probability that not all circuits will be used at full capacity simultaneously in a typical residential setting.
Q2: What types of circuits should be included?
A: Include all general lighting, power outlets, and fixed appliance circuits. Dedicated circuits for large appliances may require separate consideration.
Q3: How does this relate to electrical code requirements?
A: This calculation method aligns with standard electrical code practices for residential load calculations in many jurisdictions.
Q4: Should I include HVAC circuits?
A: HVAC circuits should be included but may have different diversity factors applied depending on local regulations and system characteristics.
Q5: How often should maximum demand be recalculated?
A: Recalculate when adding new circuits or major appliances, or if there are significant changes in electrical usage patterns.