The storm has hit and the power is out. You need to get power into the house from your portable generator now to keep some lights on, and keep the refrigerator and freezer cold without spoiling your food. You already picked up the perfect size and model portable generator (We will assume gas) and now we need to get power into the house. What are your options?
First safety rule: The Generator must ALWAYS be run outdoors in open ventilation. The fumes from operation of a generator are poisonous and will kill and a very short time. Never run a Fuel-based generator indoors, though a battery based or solar generator are completely safe from fumes.
With the generator running several feet away from the house, we need to run the power into the house to power our appliances we need to operate. For the purposes of this article we will not discuss the selection of the type of generator, nor will we discuss the power sizing issues. Both of these topics along with selection, solar/battery options, portability and characteristics are discussed in my book titled Hurricane Ready: Emergency Backup Power. Our focus will solely be in this article on the running of power from the generator to the appliances in the house.
You basically have the following options:
- Running extension cords directly from the generator to the appliances.
- Running power from the generator to an “Interlock” switch which connects to the power panel and can power ANY circuit in the house.
- Running power from the generator to an isolated secondary patch panel that powers only identified circuits in the house.
Individual Power Cords
This is of course the cheapest and simplest option. Here you can run individual cords into areas of the house to provide power. The total amount of power will be limited to amount of power available from the generator and you have to take caution not to overload the generator which will shut off if overloaded. Here are some things to remember if using extension cords:
- Don’t overload the extension cord – Cords are rated based on the amount of AMPS they can carry.
- Use extreme caution when daisy chaining cords. It is best to use single cords of the proper length.
- Use caution when connecting power strips -a power strip may be rated for more amps than the extension cord and could create a fire hazard. They can be used safely – but use caution.
- Consider using extension cords which are designed with multiple outlets on the output end. Also use high-amperage power cords. (Thicker the better)
- Always use 3-prong cords with a grounding wire. These are often designed to carry more current.
Interlock Switch
An Interlock switch is a device which allows the house power panel to be disconnected from incoming line power, and to use an alternative input source for running power to the entire house. This performs the action of isolating the home from the grid power and protecting the local grid from any backfeeding that could occur if power were to go out from the home to the grid. Backfeeding can be dangerous to linemen working to restore power and can be caused by illegal connection of a generator to the home breaking safety rules.
The Interlock switch disconnects the home from the grid and connects to an input fed by a single high-current power line from your generator. It can then provide power to all circuits in the house. The probem with providing power to all circuits is the chance you will rapidly overpower the generator. Therefore to work properly, you need to flip all breakers to equipment that should not be powered in this situation. Items such as the Dryer, Electric Stove, Air Conditioner, Water Heater, and any room outlets that could easily overload the generator. Remember your daughter’s hair dryer that pulls 1500-watts and could over power a 2000-watt or 3000-watt generator already putting out power for the refrigerator, freezer, living room for lights and tv, etc. These switches are manual devices – This means that during a power outage, you must manually intervene and you must understand how to turn off breakers that you will not need. You also must manually connect the generator as your new power source instead of the grid, and you will need to restore the grid power yourself as well.
The Interlock switch is the cheapest of your options starting off at under $200, but does require an expert to install. You can find out more about these switches at the following website:
Manual or Automatic Transfer Switch
These switches will run from $500 and up and are connected to your main switch panel. With the transfer switch, only certain previously identified circuits in the house will have power, such as your kitchen, living room, or bathroom. These are easier to use because the circuits are pre-determined and a better solution if someone else will be connecting the power. For portable generators which require manual setup and startup anyway, the manual transfer switch is going to be the best option. If however you have a generator that can start up automatically upon power loss, then an automatic transfer switch is also available. Keep in mind that an automatic generator startup process is less common and would require a permanent location such as shed or location for the generator to reside that provides safe ventilation that would not flow into the home.
Again – these transfer switches should be installed by a qualified installer only.
My Setup
For myself, I have been renting a home for the past two years until my daughter leaves for college. Once she does, I will be purchasing out of the current area I am in, but I have kept along the time a 3500-watt generator that I also use for my RV Camper. On the occasion I have had power loss I have simply used extension cords to bring power to my refrigerator and freezer, and luckily have had no power loss longer than about 8 hours.
In my next home I will be installing an Interlock switch and will operate the generator outside the home. I will be in the new home myself and will use the manual process to start it up when needed. For me however, I also have 4000-watts of battery-generator power that I have inside the home that will kick in when the power goes out automatically to keep the refrigerator and freezer operating even if I am not home.
In summary
If you are in an area that is prone to power loss and you own your home, then the best and safest methods would be through the use of an Interlock switch or Transfer switch, but plan to spend, with an electrician. between $500 and $1000. If your power loss risk is low, or you are in a rental home, then the power cord option may fit as it has for me. Just make sure you are using safe power cords properly rated for the power running through them and avoid safety risks such as daisy chaining and overloading.