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Generator Sizing

home-generator Summary: This generator sizing series describes the methods used to match your home electrical requirements to a generator system.
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Selecting the Right Size Generator for Your Home


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Install a Generator and Transfer Switch Panel

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It is Very Important to Size Your Generator.
Sizing for the essential existing loads and any future electrical loads that will be added to your home.

This series will help you understand how to size your new generator to serve your home electrical loads correctly.

The Importance of Generator Sizing

home-generator

Generator Guidelines

  • This helpful generator sizing and selection guideline will help you consider the generator size for the best value when selecting your home generator.
home-generator

Home Generator Ratings

  • This handy guide will help you understand generator ratings as it applies to your home generator project.
home-generator

7kw Generator

  • Lets take a look at generator kVA and why it is an important consideration when selection a home generator
.

Click to Download » Generator Sizing Guidelines

Comments and Questions about Generators




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One Generator for Multiple Electrical Services


Bob, from Lebec, California asks:
We have a 400 amp main panel with 3 meters so essentially we have 3 separate main electrical service panels that provide power to three separate sub panels- two separate structures and a water well pump. Is it possible to set this system up with a single backup generator and an automatic transfer switch (or three separate switches) that will power all three sub panels from the single generator when switched to Generator power, and then when switched back to main service power the three sub panels would be powered by the three separate Main electrical panels?
Thanks, Bob

Bob,
Yes, this can be done. Just as the power for all three of your existing services comes from one source, the generator power would be the one source of power for all three services as well, however you will need one transfer switch for each service, so for this type of installation the generator would need to be sized for the full potential load for all three services. Priority load shedding may be accomplished by installing current monitors that will shed one of the services if the load reached a critical point for the generator. Priority load shedding will require you to decide which of the service panels are essential and which ones are non-essential. Prioritizing the electrical load may also be accomplished at each service by connecting current monitors on larger non-essential circuits.

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Frequently Asked Questions


New and Updated about: Home Generator Sizes


Question:
What type of generator for a Clothes Dryer?
What type of generator would I need to run a clothes dryer?
This electrical wiring question came from George, a Homeowner in Thornburg, Virginia.

Answer:
A typical 240volt electric clothes dryer requires 5.5kw, or 5500 watts. Because all dryers are not exactly the same be sure to check the power requirements for your specific dryer as provided by the manufacturer.
More Generator Sizing information:
Generator Sizing Tables
Generator Sizing Calculator



Question:
Can the circuit breaker on a generator be changed to a larger amperage size?

Allen from Georgia asks:
I have a Power Boss 5500w portable generator, AC Volts-120/240, AC Amps-45.8/22.9. The 240v plug is a 30A and I need a 50A. Is there a way to change the amperage of the circuit breaker on this generator to a 50A. The equipment I need to use with this generator is 37.8A and I don’t want to risk it, or buy another generator.

Answer:
No. The circuit breaker size is set by the factory and should not be changed to a larger amperage. Installing a larger size breaker may cause the electrical components of the generator to over heat which could harm the equipment and become a hazardous condition.




More about: Generator sizing


Sizing a Generator Transfer Switch
Generator and Transfer Switch Sizing
Sizing a Home Generator Transfer Switch
Electrical Requirements for Generators and Welders
How to Prevent Generator Overload and a Tripped Circuit
How to Install a Generator Manual Transfer Switch
Home Generator and Transfer Switch Connection Video
Wire a Generator Transfer Switch Video