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Residential Panel Load Formula:
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The residential panel load calculation determines the total electrical demand on a home's service panel by summing all connected loads and applying appropriate demand factors. This helps ensure the electrical system is properly sized.
The calculator uses the residential panel load formula:
Where:
Explanation: The calculation sums all connected loads then applies a demand factor to account for the fact that not all loads operate simultaneously at full capacity.
Details: Accurate load calculations are essential for proper sizing of electrical service panels, circuit breakers, and conductors to ensure safety and prevent overloads.
Tips: Enter all loads in volt-amperes (VA). The demand factor should be between 0 and 1 (typical values range from 0.35 to 0.75 for residential applications).
Q1: What's the difference between VA and watts?
A: VA (volt-amperes) is apparent power, while watts is real power. For resistive loads they're equal, but for reactive loads VA will be higher.
Q2: How do I determine the demand factor?
A: Demand factors are specified in electrical codes (like NEC) based on load type and quantity. Consult code tables for specific values.
Q3: What are typical residential panel sizes?
A: Common residential panels are 100A, 150A, or 200A. The calculated load should not exceed 80% of panel rating for continuous loads.
Q4: Should I include HVAC in motor loads?
A: Yes, HVAC systems should typically be included in the motor loads calculation as they contain compressor motors.
Q5: How often should load calculations be updated?
A: Whenever significant electrical additions are made to the home, or at least every 10 years to account for new appliances and electrical demands.