[ARCHIVED THREAD] - Backfeeding a generator (Page 1 of 2)
Posted: 4/11/2008 6:27:51 AM EDT
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During the last power outage my neighbor who is an electrician did this. He took an extension cord with two male ends and plugged it into a non GFI outlet in his garage. He shut off the main breaker, plugged the other end of the cord into his generator and started it up. It powered his sump pump, fridge, heat and TV. He told me this is called backfeeding and is safe to do. I have done some research on the net and it seems most people are against this. Does anyone here do it? I bought this generator during the outage to pump the 1' of water from my basement. John Deere Generator |
So is that the only problem? I have been looking into a transfer switched setup, but it looks to be about 1k installed and after the french drains, new sump pump, and backup sump with battery plus the generator and 20amp 50ft cord I am out over $5000.00. |
There is the danger of not pulling the mains and sending power out over the lines, there is the danger of having a cord with 2 male cord caps, there is the danger of frying electronics in your house, there is danger of causing a fire in oyur house...... |
Bingo. You're better off just running some good heavy-duty extension cords for what you need until the time you decide to put in a transfer switch. |
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Lets see if I can make some sense of this. If you forget to disconnect your main AND any 220V circuits you will have voltage appearing in all the wrong places. A double ended male cord just aint natural. Plug the wrong end in first and you have hot prongs. Unplug the wrong end first and you have hot prongs. Other family memebers might try to use the cord and get hurt. Whats that worth? If your neutral and ground are bonded at the generator as most portables are than you will have parrallel neutral potential current carrying conductors. If there is a problem you will have odd voltages showing up in odd places. I have seen some of the new boilers with circuit boards fry because of this. Plus, what happens when you want to turn on your plasma TV (other TVs also, just using the cost angle) and it frys because of stray voltage on the ground? The same goes for computer electronics.... you will be bummed when your straight resistive loads are humming along and you want to get onto ARFCOM to brag and you end up frying your computer. Neutral-ground problems make for some very odd problems. If weird things are happening 90% of the time thats it.... the other 10% is houses wired in the 60s with aluminum wiring. When you jerry rig a generator into your house you are most of the time creating the perfect scenario for the neutral to ground problems.... if you only half know what you are doing you can get into trouble. If you manage to burn your house down you might find that the insurance will not pay for it because you did it yourself. They hate to pay out and will look for any excuse. There are two types of transfer switches.... (OK, more but I am dividing them in 2), one kind switches the hot legs only, the other kind switches the neutral and hots. Most residential transfer switches only switch the hots and leave the neutral bonded. Commercial and industrial switches are much more likely to switch the neutral as well.... sometimes as a result of the location of the panels being supplied by the standby power. A benifit to switching the neutral is it completely isolates the standby power utilization equipment from the grid. When the power goes out you will get line bumps as things are restored which can send surges down the line on the neutral.... normally the grounding connections will smooth this out, but not always. Transformers will trip and try to reset automatically and this will produce harmful surges. One thing you absolutly need to know is if the ground and neutral are bonded in oyur generator. It they are not you have one big hurdle out of the way, however, then you cannot use the gennie as a stand alone unit. If they are bonded as they would be for most 3-5K units then you need to seperate them at the generator... and reconnect them if using it as a stand alone unit. If you are just using the gennie to power a boiler or furnace its safer and easier to run an extension cord to the unit. Put a box beside the boiler with an outlet in it wired to the house system. Beside it mount a box with a strainrelief connector and a short piece of SO cord with a quality 20 male cord on it that then goes to the boiler. When the power goes out run the cord to the location and plug the boiler straight into the extension cord. Running a freezer or fridge is easy off cords also. You dont need to run the gennie 24/7 to keep things that are supposed to be cold, cold, or the house warm. Make sure you interupt the circuit before the Fire-matic so you can maintain that protection. OPS, work calls.... will add more later.... busy today so will add as I can. |
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I went back and forth on this one too... but at the end of the day... my budget prevented me from putting in a transfer switch for something that I may use once in a blue moon... and quite frankly hopefully never. If you can afford it... YES get a transfer switch... its the easiest, and safest way. If you can't afford it then use extreme caution and at your own risk. I marked clear instructions on my generator and on my fuse box of step by step instructions of connecting and especially disconnecting from start to finish the generator, main breaker, dual male plug... etc everything to do it safe... and everyone who would or potentially would be hooking the gen up, which is me and my wife... has practice and trained on doing so. As long as you take your time and follow the directions... use your head... you'll be fine. The problem tho with this set up is the minute you let your guard down... and take it for granted... you'll end up killing yourself or some poor lineman working to get the power back on. You have to be diligent in your practice like anything else. Just my 13 Cents... Camm |
 I have added to my post above..... sorry its rambling and erratic. I have been thinking of doing a long post on the good, the bad, and the ugly way to hook up generators, but never seem to find the time to do it up right. And I keep getting interupted at work today.... I really hate that! |
Could you elaborate on the above a little? I'm fairly capable at wiring and am familiar with most of what you said but I'm a little in the dark about the above. I have a brand new house. The neutral and ground are together in the breaker box. I have a manual transfer switch and it switches just the hot only. My generator is a diesel Titan 6500 watt unit but is really only good for about 5700 running. It connects outside my shop building via a proper plug. The plug runs a #8 4 wire power cord to the transfer switch and then the generator livens the entire breaker box. My generator can't handle the entire house load so I have to flip the breakers to all the 220 loads except for the water heater. Basically I want to be able to run all the basic 110 loads (staggered of course) and then run the hot water heater as needed. Thanks for the info and help. I want to make sure it's right...that why I used the transfer switch. Here is a pic of the generator panel. It's 4 wire plug so does that suggest that the generator's neutral and ground are not bonded....or do I not know what I'm talking about?  To the OP....backfeeding can be done and IF YOU KNOW WHAT YOU ARE DOING it can be relatively safe. However, I would never recommend anyone do it because there is too much of a chance to screw up in SO many ways. Save your money and do it right. My transfer switch only cost about $450 and the total cost to do it right was under $1000. Mine was a new construction so it was easy to set up right from the start. It would probably be a little cheaper to set up a small transfer switch for a few circuits. Mine switches my entire house. Hope I'm not hijacking your thread 
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Lets see how I do here..... The neutral and ground are only supposed to be together at one point in your system; the first means of disconnect. That is usually at your main panel. From there on the grounds and neutrals should be separated. Any neutral bars in sub panels should be isolated from the backbox and ground bars should be in contact with the enclosure. THe idea of the ground wire if to provide a low resistance path to ground for an electrical fault so the inrush of current will trip the breaker rather than just energize something. A toaster element uses a lot of electricity and gets hot, but it doesn't use enough to trip a breaker..... it is possible to energize something that is not grounded but not trip a breaker. That is what the little green or bare wire is for. Now, if the O terminal in the generator windings is also connected to ground at the generator suddenly the bare or green wire and the white neutral wire are run in parallel. Things under normal conditions will usually work OK. but in a fault condition now the ground wire becomes energized. Now you can end up with 190 volts phase to neutral on one leg and 50 volts phase to neutral on the other leg. Induced currents can be picked up and stray and static voltage can start appearing in really odd places. One smart guy in here in a post long gone installed a switch in the bonding jumper in his generator so he could alternate between using it as a stand alone with the ground and neutral bonded and a non-separately derived system for his house. I am running out of time here... let me know if you have more questions.... it sounds like your house is 100% and the only issue is if your gennie is bonded or not. |
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I am going to say you are good to go without looking at the owners manual for the unit. Where the problem usually comes up is with people trying to cobb a 120 volt 3 wire cord into the system. Just for chuckles and yuks look in the OM and see if it gives you any schematics. |
How can I test it to see if it's bonded at the generator? Baring anything bad happening, will things work ok if it's bonded at the generator and I liven the entire panel? Thanks a lot for the help!! 
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| Here is a long thread on the topic the last time it came up.www.ar15.com/forums/topic.html?b=10&f=17&t=607662 |
OK, now I am home with a beer in hand... I can think much better!  A quick Google came up with this.... I have not read it all the way thru, but it looks like what I am trying to say, only expressed more betterer. members.rennlist.org/warren/generator.html |
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I've done it a bunch of times. Worked great in Caribbean hurricanes for me. I went many MONTHS without "city" electricity or phone service after hurricane Marilyn destroyed the Virgin Islands in Sept of '95. They told us well ahead of time when they would be working on the lines in the area so there was no back feed since we were well informed. Not one WAPA worker got shocked and there are thousands of drunken idiots down there. FEMA radio kept everyone advised and entertained as well. They really preached the back feed issue constantly. I learned quite a bit during all those crisis. After going through that crap over and over, I told myself I'd be totally self sufficient and I'd never wait on an ice and water line ever again. Man, I'm prepped to the eyeballs now. Once you experience multiple disasters every year or so, you either leave or get with the program of serious prepping. I had a business so I chose to stick it out. If anyone is thinking of doing something like what OP describes, better to get an electrician friend to go through a dry run and write down the steps to safely carry it out after a prolonged outage. Then go through the steps yourself with him observing you for possible mis-steps or mistakes. I made a note of what breakers to throw and what outlets to power up and what is on each circuit. You want the main breaker off anyway from the get go so that when power is restored, the surge won't cook your fridge motor or other stuff. I made up a double male ended heavy extension cord for just the purpose. I would run the fridge for a couple hours in the beginning until the perishables were consumed and power up the cistern pump for shower times and a daily toilet flush or two on number two's. GROUND YOUR GENERATOR SET!!!!!! No one ever does it seems. Some folks run the piss out of the gennys or run too much load. This will overheat the windings (and compromise the insulation) and could lead to a short to the 'frame' of the set. They are not made to run for hours and hours, day after day. The cheapy sets will last a few days or a week before shitting the bed on you if you try that. The Honda's fared the best!!! |
I'm not trying to pick on you specifically - this a general response. I see this comment all the time about how dangerous a M-M cord is. It is all about procedure! You plug in the load side first and then the generator side second. End of discussion - no problems. It’s all about which way the energy is flowing. As far as family members electrocuting themselves: Everybody I live with is smart enough not to touch the bare ends of ANY electrical cord, wire, etc. at any time, little alone during a grid down situation. This is a gun site! If the average person here does not have enough common sense to follow the proper procedure or not touch bare electrical ends, then they should not have a gun either. BTW: The energy comes out of the barrel end…… |
It's perfectly safe if you know what you're doing. |
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If you're decent with wiring, it's fine if you follow the proper procedure. I have an outside disconnect, so I switch it and the i/s main breaker off (kind of a double safety). Then I plug the M-M cord (made from 10/3 with ground - works fine with my 30 amp output) in the generator and my dryer outlet. Crank the generator last. Powers up everything just fine. Of course, I'd rather have the transfer switch. Just haven't sprung for it yet. |
 Backfeeding your panel is fucked up. You risk OTHER peoples lives and not your own when you backfeed. Lets try this experiment... The power grid is down in your neighborhood. The local utility will not restore the power to the grid until you give the OK. You gear up and climb a utility pole near your house and start working on the transformer while a dozen guys who read about a cool, cheap and easy fix called "backfeeding" on the internet start plugging their gennys into the grid. How safe would you feel? You could trust these strangers, some of which know very little about electricity, to get the procedure right...right? Get a transfer switch or run a few extension cords. |
X a bazillion I'm a lineman.....my kids like me coming home at the end of a long shift. USE a transfer switch. You wouldn't go to the local gun store pick up a gun and pull the trigger without checking the chamber first. Sure you could do it and nothing might happen............. |
| The National Electric Code is revised every three years, it is the bible for electrical contractors, i dare anybody to show me in the NEC where it states it is OK to back feed a panel. If you cant afford a transfer switch than use the correct extension cords. Don't think that you can rig a system up and be perfectly safe, because if you do you are gambling not only with your life but with the lives of the guys who come in to restore power. |
I said this a few posts ago. And people continued saying it OK if ou knew what you're doing. GEt a transfer swich. ITs the best & the SAFEST way |
Dude! There is a reason they dont make them that way! People die! People forget! People are drunk and forget! People are in hurry and forget! If you make up a cord like that and someone dies you could be charged with negligent homicide! |
NO IT IS NOT! YOU CAN BURN YOUR DAMN HOUSE DOWN! |
Do you play with loaded guns? Electricity is just as dangerous, maybe more so because we are more complacent about it. The two male cord ends is dangerous.... what happens if your kid is helping a friend with something and they need a cord and your kid knows right where there is always one hanging (because it never gets used for anything else). There are inexpensive ways around the double ended male.... just do it. The grounding/bonding part of the toggled together system can burn up expensive electronics or burn your house down. It aint worth it. This is a gun site, you wouldnt have a firearm that you risked a detonation every time you dropped the bolt ("oh sure, its a good shooting gun, just be carefull when you drop the bolt cause it might go off"). Thats what you are doing whern you mess with electricity... you may not get bit this time, but every time you dont you are getting closer to the time you do! There are plenty of people that know more than me about firearms in here, but it looks like there are not that many people that get electricity.... you need to learn about it if you are going to handle it! |
I bought a 7kw generator marked as floating neutral, but it came with an extension cord for standalone use. Can you explain this? From what I understand a floating neutral should not work as a standalone. I plan to use this with a transfer switch but would also like to use it as a standalone. If I meter between ground and netural on the generator receptical I'm guessing I should see an open circuit on a floating neutral. |
Good question. Did it come with an extension cord or just a 120V receptacle? Is there a switch to go between 120 and the 240? I am going to make a guess here and say that the receptacle is GFI protected (maybe internally?) so that any difference seen between hot and neutral will trip the GFI so the bonding is not as important. I know some of the bigger Cats I have seen have 120v recepts on the insturment panel and they come as a floating neutral. I will have to check them out next time I see one. Yes, on a floating neutral you should not have continuity between neutral and ground on the 120v recptsacle. |
It came with a thick cord with a receptacle with 4 plugs on the end to connect ext cords to. I think it is GFCI but will have to check to be sure. I'll have to check on the 120/240 switch. I'm at work and can't remember. |
I bet the cordset is GFI'd. |
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This subject should be added to the "Stupid questions asked weekly on Arfcom" hall of fame. Every power company in the U.S. will tell you not to back feed. If you kill someone because you did it, you will likely be open to civil and criminal prosecution. I also don't understand the comment about being able to handle guns, therefore you should be able to handle electricity.  I've seen people handle guns at the range. That's even more reason why backfeeding should be discouraged. Handling nuclear material is safe too, as long as the proper precautions are followed. But that doesn't mean people don't make mistakes, and that accidents don't happen. |
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If you are using the generator stand alone, you should have a ground rod and attach the ground of the generator to it. I have not seen that mentioned in any of the recent threads about back feeding a generator. Not having a ground seems like a great way to BBQ the wife and kid under certain fault conditions too. |
I have an idea, would like to hear what the electricians have to say about it. First, you start off with a recessed male plug, something like this: This recessed plug would be placed on an outside wall in a weather resistant box. It would be connected to indoor receptacles that would be placed near refrigerators, furnaces, etc. This circuit would share no permanent wiring with any of the line energized household circuits. These indoor receptacles would be dead unless power was supplied to the outdoor receptacle. If the power went out, you would start the generator, run a regular extension cord from the generator to the special outdoor recessed plug receptacle, then simply unplug your appliances from the regular household receptacles, and into the generator supplied receptacles. |
That's nice. I'll stand by my statement. |
Please explain the risk of frying electronics or causing a fire? I hate to recomend "sucide cords" to any one, but they are a standard item in emergency response. Usually we use cords with tinned wires not a plug, but the idea is the same. If you don't know enough to work in a breaker panel, stay out. if you do, wiring up a generator is no more dangerious then changing a light switch (again, if you fail to turn the breaker off, you can be electrocuted. I dislike leaving cords with two male plugs arround, but there is little reason they are more dangerious then a pigtail. If you are scared someone will tamper with the setup when they see the neighbor's power come back on, for a few bucks you can buy a circuit breaker lockout to prevent the main breaker from being turned back on without removing a padlock. |
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Wow. A lot of doom and gloom in this thread. I do this (double male cord) as does all three of my relatives whom are professional electricians. My garage is on a 15A breaker, so at the absolute most we are only talking about 1650watts going into my panel. I'm not stupid, I don't load my guns before I clean them, I don't put plastic bags over my head, and I flip off my main breaker before I plug it in. I don't recommend doing it to everyone, but I also don't recommend gun ownership to everyone. Both my generators shut off when overloaded. Now, I've never tried this but I would assume that if you left your main breaker on, the load of powering all your neighbors houses would shut your generator off immediately. So I don't think backfeeding is even possible with a typical generator. |
WOW, JUST FRIGGEN WOW! Forget everything I have said..... In the future I promise I not click on threads with this subject because I obviously have no idea how to work with electricity! Darwinism at its best! Next thing ya know I will find out that its OK check firearm chambers by pulling the trigger.... after all, its so much easier than opening the action. |
Calm down. You must think you're the only one who has ever worked with electricity professionally.
Agree completely. Not for everyone, but again, if you know what you're doing, it's not too big a deal. |