1. What is Generator Sizing?

Generator sizing is the process of determining the appropriate wattage capacity for a generator based on the total electrical load it needs to support, plus a safety buffer. Proper sizing ensures reliable operation and prevents overloading.

2. How Does the Calculator Work?

The calculator uses the generator sizing formula:

Where:

• \( P_{total} \) — Required generator size in watts
• \( \Sigma P_{loads} \) — Sum of all electrical loads in watts
• \( 1.2 \text{ to } 1.5 \) — Safety factor (20% to 50% buffer)

Explanation: The safety factor accounts for startup surges, future additions, and ensures the generator isn't running at full capacity continuously.

3. Importance of Proper Generator Sizing

Details: Correct generator sizing prevents damage to both the generator and connected equipment, ensures reliable power during outages, and improves fuel efficiency by avoiding under/over-sizing.

4. Using the Calculator

Steps:

1. Calculate or estimate the total wattage of all devices you need to power (ΣP_loads)
2. Select an appropriate safety factor (1.2 for minimal buffer, 1.5 for more headroom)
3. The calculator will determine the minimum generator size needed

5. Frequently Asked Questions (FAQ)

Q1: Why is a safety factor needed?
A: Electrical devices often have startup surges (especially motors) that require 2-3 times their running wattage. The safety factor ensures the generator can handle these temporary loads.

Q2: How do I calculate total load wattage?
A: Sum the wattage of all devices you plan to run simultaneously. Check device labels or manuals for wattage specifications.

Q3: What's the difference between running and starting watts?
A: Running watts are what a device needs continuously. Starting watts are the extra power needed briefly to start motors (compressors, pumps, etc.).

Q4: Should I round up the generator size?
A: Yes, it's recommended to choose the next available standard generator size above your calculated requirement.

Q5: What about three-phase vs single-phase?
A: This calculator assumes single-phase residential applications. Commercial/industrial three-phase systems require additional considerations.