Finally got a generator for the house. Mostly, I’ll just run a cord inside should the need arise. But, would like the option of running the furnace and well and possibly water heater. I don’t really want to install a transfer switch. Breaker box is in a bedroom and the house is brick. Would be a lot of work for the couple days I need it every year. Its on a side of the house that’s very inconvenient for generator connection.
So, for permanently wired appliances, can I put them on a twist-lock plug? So I can unplug the well pump and furnace to run them off the generator? The other reasonable option is run a 60A subpanel to the basement and put a transfer switch on that. That would have easy access to run the generator cable and I could run the essential circuits from there. Well, furnace, fridge, sump pump and a couple outlets.
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For a situation where the need is but a day or two every three years corded appliances are probably easier, and safer, to run off of heavy duty extension cords and four way boxes.
this means that the fridge, and similar, will need to be pulled out enough to get to the cord. Fine if your able bodied. More of a problem if the inhabitant is small weak or infirm. Just a consideration.
Also permanently installed equipment, like the water heater and furnace don't normally come with a cord to get the power into them. The answer here, if you have some manual skills and knowledge otherwise get an electrician to set it up, is to install a wall-mounted male receptacle and a switch at each of these permanent installations.
The switch is a double throw unit, single pole for a 120v load and double pole for a 240v load, that allows the feed to be selected. The normal house wiring being used when you have utility power or, with a flick of the switch, power fed from the male receptacle that you feed with an extension cord from you generator.
The other issue, one I have seen people have problems with, is how to get the power from the generator into the house. You could crack a window or crack a door but I have seen people loose more heat than they gained through these added holes. I also saw one where the cord run through the door was severely damaged, blew a nice hole in the steel door, and could have caused a major fire if someone not been watching.
The answer here is to install a heavy duty, weatherproof, male receptacle outside near where you will be running the generator and a matching female receptacle on the inside. This allows the gen set to be plugged into the outside male receptacle and all the extension cords on the inside to be plugged into the female one on the interior. House stays toasty and there is no need to damage door seals or window screens. Saves wear and tear on the cords.
The key to this is to plan ahead and to have plenty of heavy duty extension cords, 10/2 or larger for main runs, like from the generator to the main receptacle to get power into the house, and 12/2 for branches, and splitters. These should have cord caps selected to work in the particular you decide. Note that some female cord caps won't fit certain makes of male wall receptacles. Coiled and bagged is best way to keep them. These should see no other use so they don't get damaged or wander.
I have seen this basic setup several times. Works well for limited times. When you can back the family into a interior room and rough it for a day or so. Tucked into your safe room you can get by with a few lights, a tiny space heater and a radio. The furnace would be run just long enough to keep the pipes from freezing. This will also make the gas last longer.
For the amount of time this will get used, I didn't want to do a lot of rewiring. Extension cords will mostly be fine. What I was not sure about was adding plugs to permanent units. Furnace and well primarily. Furnace is oil, so its just 120 volts. Well is 240 20 amp. I can wire twist locks in there somewhere but have never seen it done before. Can't use romex. Needs to be stranded wire. SJ cable or something like that? Will this meet code? Not that the rest of the house really does. Its an old house with a lot of "interesting" features. Had two events in the last couple years where I lost power for a week. A hurricane and a heavy snow. Having no water was probably the worst and no refrigerator the next worst. Most of the other stuff isn't as essential.
I'm in the same boat as Bob. I used to run cords from the generator, but an electrician told me I can backfeed my whole house through a line from the generator to a 220 outlet in my crawlspace. Flip off all the breakers including the main (so not to backfeed into the grid), then flip on what I need as I need it. Will that work? Don't worry, we can fix that later!
The "eletrician" who suggested doing that should be fired, have his license stripped and banished from the field forever.
It is absolutely wrong to suggest back feeding a house and depending on someone to remember to also flip off the main breaker. Maybe the homeowner gets the generator running and plugged in and then decides to turn off the main breaker. Meanwhile, his 120/220 volt output goes out to the utility pole and the transformer which transforms it to 45000 volts where it runs down the line to where the lineman is working on what he figures is a dead loadside line. The utility should permanently disconnect any household committing this reckless behavior.
~Peter
"I'm in the same boat as Bob. I used to run cords from the generator, but an electrician told me I can backfeed my whole house through a line from the generator to a 220 outlet in my crawlspace. Flip off all the breakers including the main (so not to backfeed into the grid), then flip on what I need as I need it. Will that work?"
This isn't a very good idea...a lot of people do it and get away with it, but it's against Code. You really need to have a foolproof way to absolutely prevent backfeeding power from the generator out on the grid, by using a transfer switch, mechanically interlocked main and standby breakers, or other similar method.
For home installations, really the best way to do it is to move the circuits you want to run with the genset into a small subpanel mounted right next to the main panel, and put a manual transfer switch between the two. With the switch in one position the subpanel gets power from the main panel, and in the other position it gets power from your generator.
As far as the idea of putting flexible cords on the furnace, etc., the way I read the Code book it's not permitted. It says flexible cords are not permitted "as a substitute for the fixed wiring of the structure." It does allow flexible cords for "connection of stationary equipment to facilitate their frequent interchange," but this generally applies to situations like machine tools in a factory, where they may be replaced or rearranged as required.
I suppose you could wire in small transfer switches at each appliance with one leg hooked to a male connector, and then run extension cords, but that may be as much fooling around as going with a subpanel.
I'm not sure I understand the philosophy behind some of this. I can permanently wire to a transfer switch. Then the transfer switch connects by flex cable to the generator. If I unplug a "permanent" appliance it won't run, but if somebody flips the transfer switch and the generator is off it won't run either. Seems to me it doesn't make a lot of difference either way. Either way there is some flex cable in the circuit. A plug is a good failsafe interlock. Can't accidentally cross connect the generator to the main. Well, some day I'll put in a small transfer switch if I can find one on sale someplace. Got plenty of subpanels laying around and possibly some 6/3 cable if I can find it. Just a big hassle to do all that for the day a year that I need it.
Personally, I understand your reasoning behind wanting to use flexible cords and plugs on the furnace and water heater so you can easily unplug them and connect them to the generator, and I agree that it would prevent inadvertently connecting the generator to the main, it's just that as an engineer I can't recommend doing anything against Code.
That said, hypothetically I don't know why it would be unsafe to have short pigtails off the furnace and water heater plugged into twistlock outlets right next to them...I believe their intent is to prevent people from trying to wire up their houses with extension cords.
The big message is to not backfeed the system through a welder outlet or something like that.
By the way, I checked into that Generlink device that was suggested, and it's a pretty slick device. It simply mounts in between the meter and the meter socket, so it can probably be installed in less than 20 minutes, but its use has to be approved by your local utility. It has a connector on it where you plug in the generator, and when the generator is plugged in it automatically disconnects your whole service from the utility. The connector is apparently some special design, but they provide you with the matching plug and a 20' length of cable you install on your generator. It does cost $650 including the cord, but installation labor is going to be pretty minimal. If you compare it to the total cost plus labor of installing a transfer switch and a subpanel, it's probably not too bad.
I've seen those generlink things. Nice. Also more $ than my generator. My local utility will install a propane-powered 200 Amp whole house backup system using one of the generlinks. Add the price onto the electric bill in nice monthly payments. Around $20K. I can install a small transfer switch myself. Still not convinced it will be better than cords, but if I ever sell the house and there is some really strange wiring that doesn't meet code I'd have to remove it. The small manual transfer switches have a 220 and 4 120 circuits. Plenty for the well, furnace, sump pump, refrigerator, and one string of outlets. Would not let me run the water heater for a while, then switch back and run the other stuff for a while.
I wondered how much that generlink was , pricey but not anymore than some of the other options.
Square D makes an interlock for their panels, others may also, that mounts on the cover of the panel. You back feed the generator through a double pole breaker and the interlock won't let you turn it on unless the main breaker is off.
I think it's around 50 or so, I'm not sure. That way you just flip on the breakers where you want power,depending of course on the size of your generator.
I didn't think of them the other day.
Most power companies want to know about what you install because of the danger of backfeeding on to the lines.
I think the biggest thing would be to keep it simple, so you could remember what to switch. You probably won't need it often and it's easy to forget when the powers off how you hooked something up a few years before.
You might check with your power company and see if you can install one of these. http://www.generlink.com/about_generlink.cfm looks like a safe, easy way to transfer the power.
That Generlink device looks pretty slick, thanks for pointing it out.
I'm an electrical engineer and I do a lot of municipal work -- designing wellhouses and wastewater lift stations, that sort of thing -- and I can think of a lot of places it would be pretty useful.
You know, after thinking this over, and since you've identified the appliances you want to power with the generator, why not run a new circuit and drop in new boxes for these items. My dedicated circuit for my computer uses an orange plug. You could by pass the panel and feed the new circuit in proximity to the generator - have one loop for the essential appliances, then, if you have a failure, just unplug the refrigerator, for instance, and plug it into the (orange) outlet right next to the other outlet.
This way, you'd be totally independent of the main panel, the meter, and therefore, the grid. No danger to anyone. Total cost, about $30, plus a little labor.
Greg
I would talk to the utility. Most can install a special meter base that will block current from traveling up the lines to the transformer. Remember those transformers, without the blocking, work both ways. Your generator could run 120/240v into the transformer which goes out over the lines as 4160 or 7200v. Lesser amperage but still very dangerous.
Meeting a miffed lineman whose friend has got shocked because of your generator back fed a 'dead' line would not be my definition of 'fun'. Learning that one got killed or seriously hurt would be worse. The other problem reason to avoid running your generator power onto the lines is that if the utility power gets turned on while the generator is hooked up the generator becomes a motor bucking the power plant on the other end. Don't care how big your generator is. It will loose. A generator driven like this sometimes just catches fire. Other times it can explode. Neither case does your generator, or your nerves, any good.
Everyone thinks that they will remember to turn off the main. In the heat of the moment. Remember that it is likely to be the proverbial 'dark and stormy night' when you have to get the generator up and running. Likely for the first time. Easy to forget to turn off that main.
This is why I prefer a transfer switch be installed. The system of cords is my second choice. Cords have the advantage of completely removing the house wiring, and its connection to the power lines, from the equation. This can also be beneficial if the building has been damaged, as when a tree falls through your ceiling, a lightning strike occurs nearby or in the case of flooding and the wiring system is damaged or its condition is uncertain.
I don't particularly like the generator panels. To me they seem more complicated than they need to be. The main panel already incorporates circuit protection making the breaker on the generator panel redundant. In my mind I would prefer to see a standard service rated manual transfer switch be used to make a connection to a weatherproof generator connection mounted outside of the house and near where you have the generator stored.
I have an actual engineering degree. From long ago, but I still remember some. I want something that isn't too expensive but it absolutely has to be safe. I'd never do something that can possibly backfeed the utility main. Its my house so if cords don't meet code I'd still maybe consider them so long as its a safe practical solution. Being able to switch over in 30 seconds isn't necessary for me. Very inconvenient to be without water for a week, but a couple hours is no problem. More important actually is the sump pump. If that goes off for half a day, i'm flooded. Been thinking about a battery backup pump, but that's another issue.
It's too much work, but I think a small transfer switch and a sub panel is probably what I'll install. Just have to find a good small transfer switch. I've installed those little Generac switches before and was not impressed. My generator is nowhere near big enough to run the main panel so a whole-house disconnect isn't a good idea.
Just got back from a trip but did not see anybody mention the most obvious and low cost solution -- all your loads look like less than 15A each, so simply use 3-way lighting switches as your transfer switches (center to lad, one side to box, other to gen box) , this way you also can control your load so you don't load down the generator.
Congratulations on the engineers degree. I don't think I have the mental horsepower or patience to get one so this is based on experience and horse sense.
A lot of this depends on what sort of standard of living you wish to maintain. I have used a cord setup to maintain life, limb and good order. It works well and for a few days walking over and reconfiguring cords is not a problem. The local inspector some time ago told me that he would have no problem as this would fall under 'temporary and emergency power'.
Of course some demand no change during outages and so they bite the bullet and get automatic transfer switches and large generators capable of carrying the house. These setups are nothing like cheap. We put a small one in and it ran just under $6000. Seemed a bit of a waste but they wanted convenience and an assurance that nothing as inconsequential as a hurricane would interrupt their fun. Irony being that they tried to save money on storage and only have about two days of fuel.
An intermediate approach might be to skip the generator panel and install a service rated transfer switch. For a 200A panel install a 200A transfer switch between the meter and main. The other leg from the switch would, of course, go to the generator receptacle outside. Power goes off you flip the transfer and turn off your main. Once you have the gen-set running you turn off all the breakers fed by the main.
You then turn on the main and selectively turn on any circuits you want running. Lighting and receptacle circuits can usually remain on as long as you clear the vampires, those loads fed by small transformers that remain 'on' when turned off, or any automatic loads that could come on by themselves and throw things off.
Then it is a simple matter of keeping the lighting to a minimum by turning off those lights not being used. This is one of my preferences as it avoids redundant circuit breakers while positively maintaining the vital segregation between the utility and your generator.
Refrigerators can be for a couple of hours every six to save the food. I agree that if your home is subject to flooding if the sump pump remains off a separate battery backup model would be wise. One with a trickle charger to top up the batteries would be good. In this case some experimentation might be called for to determine a schedule to run the main pump so that the backup remains unused during a power outage.
Something like a few minutes every so many hours might work. Be sure that the battery powered unit has an alarm. You wouldn't want to be counting on the backup unit only to find out the batteries are dead because it was running while you were unaware.