Portable Generators are Excellent Tools—When Used Properly
Portable generators are popular in emergencies, and for good reason. They usually output between 3,000 and 7,000 watts, enough to power a refrigerator, small appliances, and communication devices. Users can plug into a handful of 120-volt (sometimes single 240-volt) outlets and weather a power-outage in relative comfort.
It should go without saying that only a professional electrician should connect portable generators to main electrical panels. Nonetheless, backfeeding these panels from portable generators is a popular trick among homeowners.
There are inherent risks to this, however. Today we’ll discuss some of those so you can keep yourself and your home safe.
What is Backfeeding, and Why is It Dangerous?
Electricity comes into your home from utility lines. Before entering your house, a transformer throttles power to 240 volts. In your home, electricity routes through a circuit breaker and travels to appliances, lighting, and outlets.
Simply put, backfeeding involves connecting your generator to an appliance outlet (like a dryer outlet) and allowing electrical power to flow in reverse. As a result, the energy moves backward to the electrical panel and throughout the house.
Even if you think this is a harmless shortcut, you might be asking yourself, “is backfeeding a generator illegal?” Unfortunately, the answer is yes; it is illegal in most jurisdictions. It’s also dangerous because it unbalances electrical loads and strains generators.
If you don’t shut the main breaker off, power feeds back to the utility lines outside your home, potentially shocking a maintenance worker. You are responsible for injury or death in these situations and could be criminally prosecuted.
Call Cooper For a Better Solution
When used as intended, portable generators are an excellent way to power essential appliances. However, people resort to backfeeding in hopes of a more thorough backup power solution.
If you want to power your whole home, a permanent residential generator from Cooper Electrical Services is your best option. These machines tie directly to liquid propane or natural gas lines, so they don’t require manual refueling. Instead, they safely (and legally) power your main electrical panel, restoring power to all circuits.
A residential generator restores power automatically and immediately, too. The system senses power disturbances and switches on within seconds.
Call Cooper Electrical Services today to learn more about your residential power generation solutions!
If a power outage occurs and a generator 120/240 output is plugged in to a dryer outlet can the back feeding occur if the main breaker at the entrance panel is in off position so the 2 hot wires from the utility company are disconnected from the circuit panel.?
Simply shutting off the main breaker is sufficient enough to ensure power is not routed outside of one’s home.
Whenever turning off the main breaker to back feed your panel should have a patlock put on the main breaker so nobody in your home can accidentally turn it back on while the generator’s running or the linesman is working on the line Lock out tag out 1st rule of working in electricity
A transfer switch or interlock kit is a safe way to connect a portable generator to your home. These both take away the risks to the linesmen and other risks.
A standby generator is the best, but far more expensive.
Oscar said it right – noting an INTERLOCK kit is a way to backfeeding a panel safely. Of course other things need to be considered.. like not using a suicide plug but rather using the proper generator receptical. And wire gauge has to be proper. This article fails when it says “Backfeeding is Dangerous”. Heck, you might as well say powering a home with electricity is dangerous. Of course it is all dangerous if you do it wrong. But NEC allows for backfeeding a panel.
As long as you cut the main breaker or pull the meter out of the housing you will not back feed to the utility lines. I usually hook them up through the outside HVAC disconnect so it’s protected and leave the whip going to the unit detached. You will not be using the HVAC anyway. I also turn off all of the double pole breakers except for the one feeding the outside HVAC unit so it can energize the bus. I will sometimes take a section of temporary light stringer with lamp and install on the line side in a way that is easily removed so that when the utility power comes back on the light will glow and notify you. Perfectly safe been doing it for years.
Using a 220V Breaker as your Disconnect to connect a Generator to your House is not only Dangerous by in some States violates the Electrical Code.
The proper way to connect a Generator to a home is by installing a TRANSFER SWITCH
If all mains are off and or completely un lugged (extreme caution) from main exterior disco then there is NOTHING wrong with back feeding a panel… Electricity does NOT care as to where its being introduced to on the buss bars.
This comment comes from a 15 year service electrician.
Who even begins to balance a generator load in an emergency situation? Load balance would require too much effort and is COMPLETELY unnecessary for a temporarily and even most permanent off the grid situation ( unless the majority is on only one leg). Yes an unbalanced load may make the generator lose 1-4% of its efficiency but that is minor potential effect. Overall back feeding is not dangerous as long as there is 100% certainty there is NO backfeed into the power companies grid.
I forgot to mention/ask what is the difference from a grid balanced panel to the same panel that is generator powered, if one is back feeding? Nothing changed except the power source. How would someone get electrocuted in a generator back fed home any differently vs a grid powered home?
I would add that all the comment are correct. I to back feed my house when i lose power. My first rule is turn the main off before you even think generator. So you don’t get hung up and forget. With that. I am sure the power company has a rule for their safety and that is treat every wire as its hot so they are not just standing around touching wires thinking they are dead. Remember they are connecting dead wires back to live wires. They are always SAFETY FIRST. Be sure to do everything in reverse when power comes back on. That means the Main breaker is the last thing that is turned back on.
What About The Neutral?, Thanks.
If back-feeding after cutting the main breaker to the grid, the generator neutral should be floating (non-bonded), as the neutral will not be cut and you can only safely have the neutral grounded once. If using a transfer switch, it will depend on the type of switch, but the generator will still PROBABLY need a floating neutral.
I have a new 5,000 watt generator. I have 50′ 10 gauge cord that has the twist on plug into the 120v generator outlet. and the other side a 220v dryer plug that would go into the dryer outlet. My “expert” friend said that the the 120v twist on plug from my generator will not power both sides of my electrical panel. He said it should be 220v coming from my generator to power both sides. I think he is wrong. I think the 120v will back feed the whole box Note: I am aware of all shut down of panel box breakers and shutting power from my meter prior to anything. And only will use certain breakers to power fridge and oil burner and a light only as needed. I understand the safety factors. Please comment. Thanks
Your expert friend is correct. To power both sides of the panel, you need two hots and a neutral. The hots are out of phase by 180 deg. A 120 V outlet from a generator will only have one hot, a neutral, and a ground, and so will only power one half the panel.
If you have a small generator or inverter with only 120Vac output, and you use a cord as you describe and only feed one hot of the dryer receptacle, you will only feed half you panel. Only one buss. You want to feed both busses or hots. Both black and red. There is a 30Amp 120 rv to 120/240Vac twist lock adapter on Amazon that shorts the red to black lines which I use with my 3300W Firman Inverter, works fine. Since you only have 120 to your panel, all 240Vac circuits won’t work as it’s the same phase on both poles. So shut off all 240 breakers. Even any strapped 240vac breakers that feed two 120V kitchen plugs that share a neutral, as now the neutral could be overloaded as the 120 loads don’t cancel out now. So all 240VAC off except the back fed dryer breaker. And absolutely the main. If you don’t have this adapter cord, you could strap at your back feed breaker. But this is a pain, best to do with adapter plug imho. If you forget to remove the strap before returning to utility power you will quickly trip your breaker with a dead short ;).
120v feed, will only supply 1/2 of your buss. You would need a 2nd 120v lead to the other side of your buss to feed both sides.
If you look in your electrical panel, you will see that the buss alternates between breakers.
Can I use my range plug to back feed power from my generator using a pigtail? It is easier than connecting to my dryer, because it is upstairs.
I have the exact same set up. My only problem is this: I turn my main off first, then I plug in my 220v at the dryer receptacle. Being that my generator is a 110v Honda then I am only feeding 1 leg of my 220. Now the bad part about this is, my garage is on the other leg and that’s where my freezer is located. The only way I can think to get power to the other leg of my 220v would involve turning off my generator and requiring at the 220v male plug that goes into dryer receptacle. This would be a big PITA to do every time. I see a converter on Amazon. Since I do have 2 110v plugs at my generator, I may give this a try to see if it will then feed both legs of my 220V dryer breaker and solve my problem. This is a link to the adapter I found however I will need the male plug on the 220v end to plug into my dryer receptacle, so I plan to fabricate mine myself.
110/125V to 220/250V Power Adapter, Electric Converter, 10-30R Dryer Female Receptacle To 5-15P 3-Prong Male Plug. NEMA FX1455 https://www.amazon.com/dp/B084Q63WNV/ref=cm_sw_r_cp_api_glt_fabc_FTXNXWSFQ0CZ1DEZWJ2J
@Richard Dragani, your friend is correct. If you have a standard 220/240 single phase residential box, you have two 110/120 lines coming in, each out of phase to the other.
A standard 120 outlet has three prongs, hot, neutral and ground. Your four prong dryer outlet (240v) has ground, neutral, and one each of the two out-of-phase hots.
Assuming your cord is wired “properly”, you have ground-to-ground, neutral-to-neutral, and hot to only one of the two hot prongs at the dryer. That means that only one of the poles of your dryer’s breaker is powered.
If you have the two hots tied together at your generator’s plug, you are sending 120 to both of the poles of the dryer’s breaker, putting 120v to both hot busses. That would put power to all of your breakers, but any of the two-pole 240v breakers are getting the same-phase 120 to each side, so never achieving 240v. That could potentially damage 240 appliances if you accidentally turn their breakers on.
If you want to back feed your panel, get a generator with 240v out.
Your friend is correct. If you use 120 volt plug from your generator to the 220 volt dryer plug, you will only be energizing ONE hot leg (phase) in your panel. So ALL the “a phases” or ALL the “b phases” in the panel will be energized. No different then when the power company has a leg drop on their end. Only half your panel works. So any 2 pole breakers will only be hot on one leg.
Your friend is correct. You need to use 220V from a generator, not 120V. The Generator should have a NEMA L14-30r Industrial Locking receptacle that has two hot connectors, each 120 phase to ground, a neutral, and a ground. If you use a generator with only 120V then you will only power one side of your breaker panel. Some outlets may have power and some may not with this connection. If the plug you are using is wired incorrectly and places 120V across the X,Y breaker panel connections, then you will have another problem of only supplying half voltage to all the outlets. If you dont understand this, then get a qualified electrician to help you. (You sound like you need the help from your question.)
Are we over thinking this a 120 volt generator has a 3 prong which has three wires power(120) neutral and ground. Wire a 4 plug 30 amp inlet plug directly to your panel with 10/3 wire to a 30 amp two pole breaker Go on Amazon buy a 3 to four wire adapter plug with a bridged x to y
Bingo both legs of your panel are now 120 of course any 240 breakers should be turned off but won’t be damaged if you forget.
This method should not be used if you have an multi wire circuit breakers because the neutral could be overloaded!
Some of these comments are concerning. First, the original post is wrong in regard to how much power is supplied/throttled. Utilities supply your main Central Load Center (CLC) with 2 lines at 120v each, not 240v, the way the post is worded, it sounds like he’s saying utilities throttles power to 240v, its not its throttled to 120v then you have two separate connections., it’s 240v in total among the 2 lines. Now in regard to MANY comments. Those two lines from the utility company are essentially connected to two seperate power distributers inside of the CLC. Connecting a generators output of 120v then using an “adapter” to turn that output to a 240v connection in the house would result in one of two circumstances, depending on the “adapter” used, 1, the power could be suppling both lines but in doing so there would be a drop in voltage, so each line in your house would not be supplied 120v from the generator but 60v, this can result in devices plugged in to fail and/or become damaged, especially electronic devices, and pumps or the 2nd possability is the “adapter” simply allows for the output of the generator to energize one of the two lines even though it’s plugged into a two line outlet in the house, this would result in one line inside of the house to have no power. The ONLY way to properly energize both lines of a household PROPERLY, is to connect to the 240v output of a generator and when doing so, you should not use any of the 120v connections when doing so, as the larger 240v output is designed to output the maximum amount of electricity the generator is designed to produce, connecting too much to your generator has the possibility of overloading the generator and causing damage. If you have a generator that doesn’t have a 240v output, DONT connect it to your house, use as it is intended to be used as it is not designed to output 240v, this is usually the case in smaller generators which shouldn’t be connected to power a house anyways, not enough power. Hope this is helpful for everyone, just glad to see everyone is well aware to turn OFF the main breaker (utility breaker) before even connecting a generator to a households electrical system.
How can back feeding be illegal when it’s perfectly legal to sell your excess wind or solar power to the utility. Last time I heard in my state the utility has to buy what ever surplus you provide to the grid. If you notice linemen shunt the upstream and downstream lines to insure they are protected. BTW back feeding your house which is isolated from the grid can’t be illegal or it would be illegal to power your tv with a generator and extenstion cord. Its the same difference.
i have another question for emergency preparedness. I have a solar powered inverter with A 110 DC outlet. If I connect that DC outlet into one of my 110 South sockets with an extension cord and a male to male adapter will I then have 110 power in my house?
( I get that I have to turn off the main breaker during the electrical outage).
Sorry I meant to say that I would be using an AC 110 outlet from my inverter, not DC.
I had that happen last winter.power out so 1st thing go to outside. Put diconnect in OFF and lock it .
Then plugged in reg xtension cord into wash mach socket. Then special
Plug 4 dryer now both busbars in panel are live and i could get gas furnace running as well as fridge, lites an puter. It workt very well.
If u have an outside disconnect it will be in a panel that can b locked.
U shut off that main breaker outside and lock the panel so no1 can mess with it as U will be responsible for anything bad if gen is running an mains is ON.
My family and I have been back feeding power every year since we live in Louisiana and hurricanes occur
Every year and as long as you turn your main breaker off linemen don’t have to worry about me. I could never run 80 cords in my house
LMAO! AC does not ‘flow in reverse.’ Backfeeding is only dangerous if the receptacle or wiring isn’t rated for the amperage draw or the main breaker isn’t opened first.
I have been backfeeding for 23 years now..sorry if it is wrong. When I SEPERATE my house from the power company (a switch)- then it is my business…..not the governments
thanks alot of information
So shutting off the main breaker isn’t going to stop backfeading from happening?
All these comments are great. I live in PA and I’m looking for a good inverter, dual fuel, 240 volt generator to power esential items in my house. We do not loose power all the time, but I want to be prepaired since it does happen from time-to-time. Honda is premier but their pricing is quite high. Any suggestions would be appreciated,
As a follow-up to my last question, I’m a little confused as to what size inverter generator to purchase. I’m looking to power my refrigerator, oil boiler, microwave, LED lights in kitchen and two bedroom, laptop, modem/router, and 10 or so recepticals. The 9000W are very heavy, but if thats whats needed, so be it.