ask the electrician
Electrician Training Electrical Certification wiring recessed light fixtures Electrical Wiring Electrical Troubleshooting and Electrical Repairs wire outdoor light fixture Home Electrical Wiring Diagrams
wiring home generator and transfer switch wiring a 220 volt range cord outlet Wiring for GFCI Outlets Wiring Outlets and a Switched Outlet Installing and Wire Ceiling Fans and Remote Controls wire dimmer switch wiring diagrams for switches wiring a dryer cord and 220 outlet circuit breaker panel
Electrical Wire and Cable

Generator Sizing

home-generator Summary: This generator sizing series describes the methods used to match your home electrical requirements to a generator system.
© By:

Selecting the Right Size Generator for Your Home


DIY Electrical Wiring Video

Install a Generator and Transfer Switch Panel

NOTE: A List of All my Helpful Videos

Will Display at the End of This Video

So Keep Watching So I Can Help You Wire it Right!


Check out my YouTube Channel:
» AskTheElectrician «
and Subscribe!


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




related

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.

Be sure to get your copy of my BIG Book:
  electrical wiring
 
Be sure to get your copy of my BIG Book:
Perfect for Homeowners, Students and Electricians
Includes:
Home Electrical Wiring - Room by Room
120 Volt Circuits
240 Volt Circuits
Multi-Wired Circuits
Wiring Methods for Installing Home Electrical Circuit Wiring
Electrical Codes for Home Electrical Wiring
....and much more.

related

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.




Electrical Tips to Help You Wire it Right

The Safest Way to Test Electrical Devices and Identify Electric Wires!

The Non-Contact Electrical Tester
This is a testing tool that I have had in my personal electrical tool pouch for years, and is the first test tool I grab to help identify electrical wiring. It is a Non-contact tester that I use to easily Detect Voltage in Cables, Cords, Circuit Breakers, Lighting Fixtures, Switches, Outlets and Wires. Simply insert the end of the tester into an outlet, lamp socket, or hold the end of the tester against the wire you wish to test. Very handy and easy to use.

The Quickest Way to Check for Faulty Electrical Wiring!

The Plug-In Outlet Tester
This is the first tool I grab to troubleshoot a problem with outlet circuit wiring. This popular tester is also used by most inspectors to test for power and check the polarity of circuit wiring.
It detects probable improper wiring conditions in standard 110-125 VAC outlets Provides 6 probable wiring conditions that are quick and easy to read for ultimate efficiency Lights indicate if wiring is correct and indicator light chart is included Tests standard 3-wire outlets UL Listed Light indicates if wiring is incorrect Very handy and easy to use.

Strip Off Wire Insulation without Nicking and Damaging the Electric Wire!

The Wire Stripper and Wire Cutter
My absolute favorite wire stripping tool that I have had in my personal electrical tool pouch for years, and this is the tool I use to safely strip electrical wires.
This handy tool has multiple uses:
The wire gauges are shown on the side of the tool so you know which slot to use for stripping insulation.
The end of the tool can be used to grip and bend wire which is handy for attaching wire onto the screw terminals of switches and outlets..

The wire stripper will work on both solid and stranded wire. This tool is Very Handy and Easy to Use.

portable-generator

Generator Parts and Accessories


Portable Generator Cords

Generator Interlock Kit

Generator Transfer Switch

Transfer Switch Kit - 30 Amp 10-Circuit

200 AMP Smart Transfer Switch - Single Phase Generator Controller

6000 Watt Portable Generator

12000 Watt Portable Generator



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