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 factor to account for startup surges and future expansion.

2. How Does the Calculator Work?

The calculator uses the generator sizing formula:

Where:

• \( P_{total} \) — Recommended generator size in watts
• \( \sum P_{loads} \) — Sum of all electrical loads in watts
• \( 1.2 \text{ to } 1.5 \) — Safety factor multiplier

Explanation: The safety factor accounts for startup current surges (especially for motors) and provides capacity for future additions.

3. Importance of Proper Generator Sizing

Details: Proper generator sizing ensures reliable operation of all connected equipment while preventing overload conditions that could damage the generator or connected devices.

4. Using the Calculator

Tips:

1. Calculate the sum of all electrical loads you plan to power (in watts)
2. Select an appropriate safety factor (1.2 for minimal headroom, 1.5 for heavy motor loads or future expansion)
3. The calculator will recommend the minimum generator size

5. Frequently Asked Questions (FAQ)

Q1: Why is a safety factor needed?
A: Electrical devices (especially motors) often require 3-7 times their running wattage during startup. The safety factor ensures the generator can handle these temporary surges.

Q2: What safety factor should I choose?
A: Use 1.2 for resistive loads (lights, heaters), 1.3 for mixed loads, and 1.5 if you have many motor-driven devices (AC units, refrigerators, power tools).

Q3: Should I consider future expansion?
A: Yes, it's recommended to add 20-30% capacity beyond your current needs if you anticipate adding more equipment later.

Q4: What about three-phase vs single-phase?
A: This calculator provides total wattage. For three-phase systems, you'll also need to consider voltage and phase balance.

Q5: How do I find my appliance wattages?
A: Check nameplates on devices, owner's manuals, or use a wattmeter. Many appliances list both running and starting watts.