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.
Perfect for Homeowners, Students and Electricians Includes:
Generators and Transfer Switches
Electrical Codes for Generator Installations
Generator Transfer switch Wiring Diagram
Wiring Methods for Installing Electrical Panels
....and much more.
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.
What is the Basic Wiring Configuration for a Generator Transfer Switch: Each Wiring Termination must be correct for the Power Conductors of the Line or Load.
How should I install the wiring to connect a generator to my home? Planning and Installing a Generator with a Transfer Switch: How to Connect a Generator to a Home.
How to Connect a Generator to a Home: Safe Methods for Connecting a Home Generator, Approved Transfer Switch, Circuit Breaker Interlock Kit, Well Pumps and other 220 Volt Circuits, Sensitive Electronic Devices and Equipment, Connecting the Generator.
Here are the Steps for Sizing a Generator Transfer Switch: The rating and size of all the electrical components of the system should be sized properly.
How to Select the Right Generator Transfer Switch: How to Save Money on a Generator Transfer Switch - These two items actually work hand in hand, and the end result will actually be how large the generator will be and there are a few more options that may be much easier to install and much less costly that a large transfer switch.
Why you should never connect a generator in such a way as to back-feed your electrical system. This is extremely dangerous not only to your home but also the electrical utility crews who may be working on downed electrical wires.
Installing a Home Generator
Electrical Project Skill Level:
Licensed Electrical Contractor, Not Recommended for Homeowners.
Electrical Tools Required:
Electricians pouch of hand tools and the various power tools necessary for installing the generator and transfer switch. Estimated Time:
Depends on the type and size of the generator and transfer switch and the available access to the project area. Electrical Safety:
Any existing electrical wiring within the immediate area that may interfere with the installation of the transfer switch may need to be relocated if necessary.
Electrical Wiring Parts and Materials:
Electrical parts and materials for generator wiring projects should be approved for the specific project and compliant with local and national electrical codes.
Electrical Codes and Inspections:
Installing a generator and transfer switch must be well thought out and performed with a permit with all work being inspected.
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A wire stripping tool used to safely strip electrical wires.
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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.
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