The following is a chapter from my book, Small Power Planning. I wrote the book to help guide readers through the ideas of planning a backup power plan for emergencies. In the book I cover discussions about both Fuel based generator systems and “Small” solar solutions that are both portable and much more affordable than whole-home power solutions. During an emergency you may find yourself in need of some sort of backup power solution to provide limited power for a few days or even weeks. Usually whole-home power solutions will run anywhere from $7,500 for whole-home fuel generators, up to tens of thousands for a whole-home solar system.

But – What if you need it for a short time only or need to take it with you when you relocate, either for an emergency or simply when moving. And – What about apartment and town home dwellers unable to use a whole-home solution?

I have provided this chapter for several folks who I have spoken to inquiring specifically about how to connect a portable power solution for use in the home.

Chapter 6: Getting it all Connected to the House

With the use of a Portable generator, you need to decide how you are going to use the electricity and get that electrical power indoors. You have multiple methods of connecting your home to a fuel generator, ranging from simply running extension cords from the generator to installation of a transfer switch mechanism that allows you to run power directly from the generator into your electrical panel for distribution.

Connecting the house – any way you look at it – is a task that must be planned out. If you go with the simpler extension cord method, realize that you first must have enough extension cords, and then realize that they must stretch into the house to provide power as needed.

To get the electrical power into your home you have several options:

1. Extension Cords
   This option is cheap – But it is also more difficult requiring multiple extension cords. That said, it may be your best option if your needs are rare. It does introduce hazards with energized cords running on the ground, but if your need is rare, this option does not require the installation of a permanent transfer mechanism to the home.

Automatic Transfer Switch
The Automatic Transfer switch is the easiest functionally – but it is also the add cost and will be more common with larger stand-by generators or large solar systems to allow power to immediately be restored during a blackout. This system allows power to come from the generator directly into the home’s electrical panel and then power only certain circuits within the house for emergency power. For most portable solutions, since the generators do not auto-start, an Automatic transfer switch is not necessary. Some generators however, if they have a battery start, can have automatic startup switches added allowing you to have a portable generator auto-start and provide power for the house through an automatic transfer switch. Note for this the generator needs to be housed outside in an enclosure where fumes will not get into the house.
This would be the best option for power to automatically restore if you would have kids or family unfamiliar with an automated switchover process.

Manual Transfer Switch
The manual transfer switch allows power also to run into the home and through the existing home circuits but is a manual process to get power back up and running. If your backup power generator system is a manually started portable generator, then this system will work well as restoring power but will require the homeowner to take some action to start the generator. This option is less expensive than the Automatic Transfer switch option above. This option requires intervention from the homeowner to cut over to backup power.

Interlock Switch
This is the least expensive option which allows us to isolate our existing home circuit breaker from the normal incoming power lines, and instead power our entire circuit breaker from our generator. This choice still requires a manual intervention to re-energize the home, and it will also mean that the homeowner, when switching over to the generator in the process, needs to manually shut off circuits that are not needed or risk overloading the generator.

For instance – If you are switching over to a 5,000-watt backup generator, in the process by turning all circuits not needed during this “Backup” mode such as you’re Air Conditioner breaker or guest rooms, you can reduce the chances of overloading your generator. A large home Air Conditioner alone may take most or all your generator power which usually will trigger a shut down by most generators when overloaded.

http://www.nooutage.com/interlock_kits.htm

There is another method which is NEVER recommended – And that is use of a Male-to-Male extension cord. These cords are also called “Suicide Cords”. There are multiple reasons for this to be a hazard:

1. Once plugged into the generator, you have an unsafe second end to the generator with open contacts that are energized and live – This is an extreme shock risk!
   
   
2. Using this to feed power into your home will also back feed power to the power lines and create an electrical hazard for linemen working to restore power to the area.
   
   
3. This is ILLEGAL in most communities, and you will open yourself up to criminal Negligence charges as well as liability if an accident occurs with one in use.

NEVER USE A DOUBLE-MALE EXTENSION PLUG TO BACK-FEED POWER INTO YOUR HOME. These are Dangerous and again – Illegal!

The installation of any of these transfer switch methods goes beyond the scope of this book and will be unique based on your specific needs as well as the switch method and manufacturer you are going to use. We strongly urge you to contact a licensed electrician only for proper installation based on your needs and your local electrical codes.

If you install a manual cutover switch, then getting power back to your house would generally follow the following steps:

1. Get out your fuel generator and prepare it for use. (Set it up outside only, 15 feet away from the home, with exhaust pointing away from your home, windows, and doors.)
2. Connect your generator to a pre-installed outlet that connects via the transfer switch to the home.
3. Start the generator
4. Switch your transfer switch from normal line grid power to your secondary generator source.
5. Selected circuits should now be active with power running to them.

Keep in mind with most manual switches, only certain circuits will be energized in the home based on a pre-planned strategy you will work out with the electrician installing the switch.

For an Interlock Switch, the cutover steps will be similar however there will be some differences since the entire breaker box will be energized rather than just those pre-planned.

1. Get out your fuel generator and prepare it for use. (Set it up outside only, 15 feet away from the home, with exhaust pointing away from your home, windows and doors.)
2. Connect your generator based on switch installation to the home.
3. Start the generator
4. On your Breaker box – AND THIS IS IMPORTANT – Switch OFF all circuits not needed during this blackout. Most likely this will include your Air Conditioner, Water Heater, Electric Stove, and any rooms you determine not needed. FAILING THIS STEP MAY OVERLOAD YOUR GENERATOR.
5. Switch your interlock switch from normal line grid power to your secondary generator source.
6. Selected circuits should now be active with power running to them.

Specific circuits will now be energized based on your installation decisions. Only these rooms will have power available. Any lights and power outlets in these rooms will now work as normal using the power from the generator. When the power restores you will reverse these steps to switch back to the grid power.

Cost of a cutover switch generally will run from a couple hundred dollars to several hundred depending on what and how you are setting it up. Again, we emphasize, unless you have the training and experience, DO NOT DO THIS YOURSELF – Use a licensed electrician for all home electrical modifications. Electricity is deadly and you can easily make a mistake that could put your life or the life of another person at risk.

Transfer Switches – 120v and 240v

When planning a backup generator solution and planning to use a transfer switch or an Interlock, consider the voltage levels needed within your home. Many smaller generators will not provide 240-volt power for appliances requiring that much power, and likewise if you do need a generator and power for 240-volts, that needs to be planned also for your switch over installation. Several newer and larger inverter generators will now produce useful 240-volts if needed, though these may be limiting in current.

An RV 50-Amp system can be plugged into many 240-volt generators which can provide the split service that the RV is looking for, however usually you will NOT get the 50-Amps on each leg that the RV may be looking for. This does not mean it will not work – just that you won’t get the full 50-amp service.

Using a Cutover switch with a Portable Fuel Generator, or a Solar Generator system

The installation of a cutover switch or use of extension cords as we have talked about in the pages in this section serves the purpose of handling the power distribution into your home from an alternate power generation point. But what about the power source itself?

If you are installing a whole-home power generator solution, either solar or fuel based, then your power system will be wired into the home, and in most cases an automatic switch will be used to make your cutover automated. But – If you are using a portable generator or a solar generator you will need a point to plug into. In these cases, your electrician will install an outlet box similar to the outlet box shown here to the right that will supply power when the cutover is made from the commercial power to the home. You would then simply run a connecting cable from your power generating source (Gas/Propane/Diesel Generator or Solar Generator) to the newly installed outlet box.

In the image both to the right and left we see a 4-prong connector for a 30-amp connector. The exact connection you will use may vary based on the power source you are using, and if you are supplying 30-amps, 50-amps, or other types of power into the home from your generator. The point is though – properly set up, all you would need to do to power your home with the right connection switches installed would be to literally “Plug” your home into your generator. For me – I have a 3000-watt portable generator that I can plug into my home system to power only a few needed circuits in the house – Kitchen, Refrigerator, Freezer, Bedroom and one bathroom. Using an Interlock switch, I would manually shut off all other circuits to avoid overloading the generator. At night when I want to secure my generator, I would plug my refrigerator and freezer into my solar generator which has 2500-wh of stored energy, then use a smaller portable solar generator for use as needed elsewhere in the house.

My Gas generator has a recommendation to run for between 12-16 hours and then a two to four hour rest period which gives me the day to power the house and use rechargers for the solar generator batteries, and then I operate quietly at night on the Solar/Battery power generators. Alternatively, I can use up to 800-watts of solar, provided power