I am planning on getting a generator incase of a long term loss of power. So far that has never happened to me, but I want to be prepared.
If such an event would occur, I would "open" the main breaker, then use the generator outside in back of my house to "back feed" through an outside GFI outlet. Note: I have no interest in whole house power, but power for the refrigerator and some low power devices.
I was planning on replacing the GFI outlet with a "regular" outlet, but a friend told me he once used his generator and "back feed" through a GFI outlet without a problem.
Does anyone know if "back feeding" through a GFI outlet is OK?
Whatever you do, *don't* try this without a proper transfer switch. You can burn down your house, and even worse, you can kill a utility lineman. (Those pole pig transformers work backwards too.)
A transfer switch doesn't have to be fancy--you can get ones that are just a sliding piece of metal that attaches to the breaker box and prevents the main breaker and the generator from being connected at the same time.
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Failing that, use heavy duty extension cords, connected point-to-point right to the loads.
But really, really don't try the male-to-male cheater cord approach.
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Cheers
Phil Hobbs
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Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510
hobbs at electrooptical dot net
http://electrooptical.net
It is NOT ok, GFI or regular outlet. The technique is often called a "suicide cord" where you have a power cord with a male power plug at both ends. One goes to the generator, the other into a wall outlet. Lots of problems.
If you forget to disconnect your house from the mains, you're going to either power the rest of the neighborhood, or electrocute the utility company employee trying to restore the power.
Your house is probably wired with two phases from the transformer on the pole. The neutral wire carried the difference between the two phases. If you backfeed one phase, the neutral is carrying the entire load. If you had a two phase generator, and try to backfeed both phases, you will to identify which wall jacks have each phase, and then build an even bigger suicide cord with plugs for both phases. If you do something really dumb, like parallel the phases, you'll overload the capacity of the neutral wire and possible start a fire.
Generators are rated by their TOTAL power. Most home generators supply two phases, each with HALF of the total power. If you try to run your house with a generator with only one phase loaded, you're going unbalance the generator and potentially cause a bearing failure. At the least, it's going to sound rather funny. If you try to load the generator to full capacity from one phase, it will likely shut down in protest from overload.
Powering the entire house is wasteful and messy. Do you really want to run around the house and turn off or unplug everything that doesn't need power during an emergency?
As Phil Hobbs suggested, get a transfer switch with a safety interlock. They come in various flavors and sizes, but all are far better than a suicide cord. If your generator is portable, get a transfer box with an appropriate connector rather than permanently connecting your generator.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Assuming the power rating of the generator was just enough power for when the fridge is on, would such a generator be able to start with the fridge compressor load in line and on, when powered up? How much of power headroom required to overcome such an initial load, should the owner not be aware of this , and wait and not power on the fridge when the gen is up and going.
I found a good deal on a generator at a garage sale. I found another good deal on a DIY transfer switch at another garage sale. These were both impulse purchases with no opportunity to research.
When I got around to setting it up, I discovered that the permit fees exceeded the cost of the hardware. There were other issues where the national electrical code seemed to specifically prohibit things that the inspector said would be ok. And since the electrical service doesn't meet current code, there's risk that messing around in the breaker box might require some other major COSTLY changes. Opinions vary.
I currently have two small generators, neither of which runs. At one time, there were four generators. I bring home obvious repair jobs in the hope that I would find the time to repair them. Somehow, it never happens.
There are two types of transfer boxes. The one that connects on the utility side requires utility company involvement and can be expensive. If your transfer box is designed to work with an autostart type generator and/or you plan to power the entire house, you need this type.
The type that installs on the load side of the breaker box, is much easier to deal with, does not require utility company involvement, and is treated by the county as a secondary breaker box. Any competent electrician can do the work. I don't recall the exact permit fees, but I think they were about $150 as of a few years ago. Something like this:
Welcome to the real world. One of my friends finished a custom home last year. Inspector 1 would show up and declare everything to be wrong. After changes were made according to Inspector 1's opinions, Inspector 2 would arrive and declare that it's all wrong and should be done yet another way. The process is endless and seems to be designed to keep general contractors and inspectors in business. Reciting NEC code chapter and verse to the inspector does nothing useful. We even have examples of the county breaking state law, and not caring because they know it's too expensive for a homeowner to run it through the courts.
Yeah, that's a problem. As soon as they find anything that's not to current code, they will sometimes make you bring the entire house up to specification. You could be doing a minor electrical modification, but the county will sometimes turn it into a major project. This tends to discourage homeowners from obtaining permits. The major incentive is that the homeowners insurance company will not use non-permitted construction as an excuse to not pay a claim.
Yep. Cheap, easy, and versatile.
Incidentally, one of the neighbors nearly had a fire trying to run his freezer, fridge, electronics, and who knows what else, from a series of cheap 16/3 extension cords. Make sure the extension cord can handle the load. Also, make an effort to balance the load between the two phases.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Probably not for auto-transfer. The generator would have to supply the total connected load.
The transfer switch below is more likely to be auto-transfer. It only runs selected loads which a properly sized generator can supply.
A third approach is in Phil's post. You install a breaker in a top position in the service panel and backfeed it from the generator. A mechanical interlock on the door prevents the service disconnect and generator breaker being on at the same time. Phil gave a source for the interlocks. Some panel manufacturers also sell them.
I agree with others that a "suicide cord" is a real bad idea. For an easy to disconnect connection a proper method is to use an "inlet" with appropriate ratings:
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The cord from the generator to the inlet is a normal extension cord with the appropriate rating and ends. With a transfer switch or interlock, the prongs of the inlet will never be live.
I bought one of those for a buck. And a new 5KW generator for $100. Were those "Can'tPassItUp" deals that I later regretted. I have some really nice cable that can easily handle the generator interconnect, but it doesn't have the proper markings, so wouldn't be strictly code compliant either. An additional $150 for a permit and iffy approvals killed my ambition.
I asked about interlocks and was beat bloody in the newsgroups that those were NOT legal under any circumstances. Didn't really matter cuz...
My box has 5 primary breakers each supporting a set of secondary breakers. Since there's no single disconnect, I have no way to get from one branch to another using an interlock.
Next time we have a substantial power outage, I'll dump the whole lot on Craigslist.
the compressor in a fridge isn't too bad. Being able to shut off the defrost cycle coils might help a big during a power outage though. They waste lots of power.
sadly the only way to get a good extension cords these days is to make your own.
goto the hardware store or electric supply and get some good rubber cord and some real plugs and make a receptable box.
I'm terrified by the shit they sell as extension cords these days. The contact are always utter crap, the crips are usually corroded by the cheap plastic and they are going to burn up at more than a 3 amp load.
If you're a contractor doing work an a cord burns up running a chop saw, no big deal.
When the Y2K mania was in full swing, my wife let me buy a small generator. We had a really messy ice storm some years ago, and I knew power was going out when I could hear major branches falling at one second intervals. When the juice went off, I went to the basement and rewired our furnace to a power plug, brought in the extension cords and went to bed, About 6 AM, my wife woke me and said it was freezing. So, I started the generator next to our garage, plugged the extension cord in, and powered our fridge, freezer and furnace, and charged some batteries. Even before the generator ran out of gas, it was warm in the house, and the fridges were cycling normally, so I shut it down. I was just about to do it again when the power came back on. (There is an advantage being close to the substation with no HV fuses between, you get your distribution line up first.)
I was recently talking with a utility lineman who brought a TV in here for repair. We were discussing this very thing. I told him that I wouldn't want his job for any salary. He told me that back feeders who are not smart enough to kill the main are a constant problem. There was a case here a few years ago where a lineman was critically injured from a back fed secondary. I'm also told that if an electrocution should take place the AG might seek a manslaughter conviction. So "how" I asked do these poor guys protect themselves against these bozos? There are apparently a number of ways this is done. First, with utility power off on the primaries the guys ground the line, (phase) on each side of where they're working. This does two things. first it protects them against 240v induced into a pole pig's secondary and second, as long as Mr. Bozo's generator connects to house neutral at some point, which it would if he's using a suicide cord etc, it should trip out the breakers on the generator or smoke it. They also have inductive poles they can hold near a line that will light up and sing in the presence of primary voltage. I still wouldn't want the job. Lenny
I was recently talking with a utility lineman who brought a TV in here for repair. We were discussing this very thing. I told him that I wouldn't want his job for any salary. He told me that back feeders who are not smart enough to kill the main are a constant problem. There was a case here a few years ago where a lineman was critically injured from a back fed secondary. I'm also told that if an electrocution should take place the AG might seek a manslaughter conviction. So "how" I asked do these poor guys protect themselves against these bozos? There are apparently a number of ways this is done. First, with utility power off on the primaries the guys ground the line, (phase) on each side of where they're working. This does two things. first it protects them against 240v induced into a pole pig's secondary and second, as long as Mr. Bozo's generator connects to house neutral at some point, which it would if he's using a suicide cord etc, it should trip out the breakers on the generator or smoke it. They also have inductive poles they can hold near a line that will light up and sing in the presence of primary voltage. I still wouldn't want the job. Lenny
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I don't know about electricity supply but this is what they do on UK railways. At least like in our area with the third rail at ground level. When the ground crews have possession of a piece of track a shorting bar is clamped between the rails at either end of the possession. These bars are then tested regularly at Southampton University , that they will carry 5,000 amps or whatever the rated figure is.
I removed the GFI outlet and installed a "regular" 20A outlet. Note: Wire to that outlet is 12 gauge. Also, that outlet is on a 20A circuit breaker. The generator I am waiting for has 20A outlets.
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