So you want to know how to back feed your home with a portable generator during a hurricane or other power outage.
Backfeeding is very dangerous. It is also a code violation. The recommend way is to use a transfer switch and or a licensed electrician.
But I know that most people will wait until a hurricane has already come and they are without power. So they’ll try and do it themselves. In hope that this page may help save someone’s life when they need the power and cannot get a licensed electrician, like a hurricane, I am posting this page. If you still choose to backfeed be sure to read What To Do When the Power Comes On.
If you are going to backfeed your home, you must be very carefully and follow the directions below. If you fail to follow them you can kill a line worker, kill yourself or blow up your generator. Again I’ll say, get a licensed electrician.
Step One, the most important step of all is to turn off the main breakers.
Step two, turn off the main breakers.
Step three, turn off the main breakers. Do you get the idea?
Step four, remember to plug the generator end in last. If the generator is running and you are using two male ends the house end plug is live!
Step one, The first thing you will need to know if you refuse to get a licensed electrician is how many amps of continuous power your generator is capable of producing. 1000 Watts at 120 volts = about 8.3 amps. You also need to know what each appliance or electrical item you plan on running uses. You do not want to overload the generator, you’ll burn it out or worse, ruin your appliances, so get a licensed electrician.
Step two , find your circuit breaker panel box. Turn off the main breakers. They are normally at the top and are marked “Main”. They are normally 100, 150 or 200 amp breakers with a connect bar connecting the two of them together. The main breaker looks like a 240 volt breaker, but slightly larger. If you cannot determine which breakers are the main breakers, do not continue. There is no second guessing. Get a licensed electrician.
Once the mains are off, turn off all the other breakers in the panel box. DO NOT START THE GENERATOR until all connections are complete. Never turn on the main breakers when the generator is connected to your house.
Step three , determine the location you are going to operate your generator at. It cannot be in a garage, under or near a window, nor in your home. It must be outside and far away enough so that the exhaust fumes cannot enter the home. Once you determine the location the generator will be used, you need to determine how far away the source of back feeding will be.
Step four , you must calculate the amount of amps or watts that you plan on using with the generator. You cannot exceed the units total continuous power. Every 1000 watts is about 8 amps.
(watts / volts= amps or 1000 watts/ 120 volts= 8.3 amps). You cannot put more than 15 amps on any leg of the generator. Each wall outlet on the generator is a leg, even though it as two plugs inlets. A wall outlet has two inlets, it looks just like an outlet receptacle in your home. Each 240 plug on the generator has two legs, two 120 volt lines. Appliances that are rated at 110 volts will draw more amps but less watts (1000 / 110 = 9 amps). Each 120 volt wall outlet will produce 15 amps. That is 30 amps that can be drawn from two wall outlets on a generator. The 30 Amp 240 will produce 15 amps on each leg of the 240 line, that’s another 30 amps.
Note: some generators have a 30 amp 125 volt plug. This is equal to the two wall outlets, but not equal to a 30 amp 240 volt outlet. You cannot run any 220 volt appliances with a generator that has a 30 amp 125 volt plug.
Step four , now you need to know how you will backfeed from the generator. The first thing you must do is determine the method you can use with your generator.
- Does your generator have one wall outlet, enough outlets to plug two extension cord in? Use method 1
- Does your generator produce less than 3000 watts of continuous power? Use method 1
- Does your generator have 2 wall outlets, enough to plug 4 extension cords in and no 240 volt plug and produce at least 3000 watts? Use method 4
- Does your generator have 2 wall outlets and a 30 amp 125 volt plug? Use method 5
- Does your generator have both a 240 volt plug and two wall outlets, and produces less than 7000 watts but more than 4000 watts of continuous power? Use method 2
- Does your generator have both, a 240 volt plug and two 120 wall outlets and produces 7000 watts or more of continuous power? Use method 3
Method 1: I suggest that you use extension cords to power up your refrigerator and a few lights. Forget about backfeeding. You must use the correct size wire in your extension cords, and they should be as short as possible. The longer the extension cord the greater the voltage drop. A 16 gauge line should not carry more than 9 amps. A 14 gauge extension cord should not carry more than 15 amps, and 12 gauge can carry up to 20 amps. Do not attempt to back feed using any of these extension cords. Do not over load the generator by powering up more than the unit can handle.
Method 2: If your generator cannot produce at least 7000 watts of continuous power, your unit cannot produce 60 amps or more. If you have a 240 volt plug you can use the following method and the amount of amps your unit can produce over 60 can be placed on extension cords; see method 1. If your unit is less than 7000 watts you can only use method 2. Purchase some 10/2 or gauge wire long enough to reach from the generator to your dryer outlet, or other 220/240 appliance outlet. Ten gauge wire can carry up to 30 amps on the Black wire and 30 amps on the White wire. Wire the 10 gauge wire to the 240 volt plug; placing the Black wire on the brass colored screw, the White wire to the Silver colored screw, the bare wire to the Green screw. You will also need to purchase a 240 plug that can be plugged into your dryer outlet, or other 220/240 appliance outlet. If you do not have a 220/240 outlet appliance you will need to wire the line directly to a 220/240 circuit breaker.
Note: the Black wire will be circuit A and the White will be circuit B.
If you generator produces 5000 watts or more and has a 240 volt plug you can use this method plus method 1 up to the limit of your unit. A 5000 watt unit can produces about 42 amps. Do not attempt to run more items than your generator can handle.
Method 3: If your generator has at least 7000 watts of continuous power than you can use method 2 plus method 1. You unit produces at least 58 to 60 amps. Do not attempt to back feed using more than one method. Use a single method to back feed and power up other items using extension cords directly from the generator.
Method 4:You must remember that if you backfeed through an extension cord the total length of the line is the house wiring plus the length of the extension cord. The longer the line the more the voltage drop. Do not attempt to back feed using more than one method. Use the shortest extension cords possible.
Purchase two 12 gauge extensions cords no longer than needed. The first extension cord will need to be long enough to reach from the generator to the closest wall outlet in your home. The second extension cord length will be determined when we located Circuit A and Circuit B. Also purchase two male ends to be attached to these extension cords. Cut off the female ends and install a new male end to the cord you cut. You now have a cord with two male ends. The Black wire gets wired to the Brass colored screw, the White wire goes to the Silver screw and the Green wire goes to the Green screw. You will not be able to run any appliances that are 240 volt with this method.
Method 5:If you have a 30 amps 125 volt plug you can use either method 4 or the following, but not both. You can also use method 1 for appliances or lights if your generator produces more than 4000 watts. Do not exceed the units total wattage. This method will NOT make 220 power.
You will need to purchase 10/3 wire, long enough to reach from the generator to a 240 volt plug. You will also need to purchase a 220/240 plug that can be plugged into your dryer outlet, or other 220/240 appliance outlet. If you do not have a 220/240 outlet appliance you will need to wire the line directly to a 220/240 circuit breaker.
To wire 220 plug (the dryer), wire the Black wire to the Brass colored screw in the plug. The White goes to the Silver screw, the Green wire to the Green screw and the bare wire to the Black or ground screw. This will put 15 amps on each leg. To wire the 3 prong 125 Plug (generator plug), wire the Black and White wire to the Brass colored screw, the Green wire to the Green Screw and the Bare to the Ground. Click on the below image to enlarge.
Once you have determined which method you will be using, and plan on using extension cords to backfeed, you need to know how. You cannot not backfeed using both method 3 and method two, you will blow up the generator. With no cords plugged into the generator, and ALL circuit breakers of, INCLUDING THE MAINS, turn off or unplug all appliances, TVs, computers, lights and anything else that is electric. Place one extension cord into the 120 volt wall outlet that you plan on using to back feed your home and the other end into the generator’s 120 volt outlet. Start the generator let it warm up. Turn on all the single 15 or 20 amp circuit breakers. Do not urn on any 240 volt breakers(double breakers), or the main breaker. With a lamp or test light, go around the house plugging the lamp into each outlet, until you find all the outlet that works.
As you find ALL the outlets that work, write a list of the ones that work. This will be circuit A, label the list circuit A. The outlets that do not work will be labeled Circuit B.
Turn off the generator and than unplug the extension cord from both ends. Remember to turn off the generator before unplugging the extension cord you made! Now you will need an extension cord with the two male ends long enough to reach from the generator to the closest outlet that did not work, our Circuit B.
You are now ready to using your generator during a power outage or hurricane.
- Turn off the Main circuit breakers
- Turn off all circuit breakers
- Make sure the Main breakers are Off
- Plug one cord into Circuit A from one of the wall outlets on the generator.
- Plug the second cord into the other wall outlet on the generator and into Circuit B.
- Turn off or unplug all appliances that the generator cannot support
- Start the generator, let it warm up
- Turn on one single 15 or 20 amp circuit breaker at a time. Wait about 5 seconds before turning on the next breaker.
- If you back fed with 240 volts and have a 240 volt appliance to run turn it on last.
What To Do When the Power Comes On
When you are sure the power is available from the power company, you need to turn off the generator first. Unplug the extension cords from both the generator and house. Unplug any backfeed line you used. Now double check that all lines as disconnected form the house and generator. Now triple check the lines, are you sure they are disconnected?
Ok, they are disconnected. Turn off all breakers, than turn on the Main breakers and than turn the rest of the curcuit breakers back on on at a time. Allow several seconds between each breaker turn on.