Hi all,
After our last three day power outage over the holidays I have decided to invest in a generator and a transfer switch in order to run thru my panel. I thought I would start here to get a primer on the basics of a transfer switch from any resident sparkies. I’ve always done my own wiring and am comfortable working in the panel etc. Could someone explain the setup for such a system. Its my understanding that you run from a generator into a transfer switch which then runs to the panel to energize it. Questions are…… Where or what do you wire to? Do you energize just one hot bus. I need some specifics and any caveats that are invoved with such. Thanks
Replies
first things first.
Do you want to power the whole house off this genny or just essential circuits?
You need to size the generator to that decision. A 500 dollar unit will not do a whole house. We have set up a couple houses on 6000W units to run four to six essential circuits, which need to be separated out on a subpanel. Running the whole house will take a far larger machine but simplify the wiring somewhat.
You might also need to have approval/inspection fom the local utilities supplier. They like to make sure their workers are not getting electrocuted during storms.
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I would just want to power essentials such as furnace fan, fridge, freezer(thats ironic) and some lights. These are high use items so I figure at minimum a 5Kwatt unit. My understanding is that you should be able to run this in to your panel, essentially backfeeding the panel. You shut off the main so that nothing goes back out the incoming line and then shut down all the breakers but those that you need to run. A separate subpanel seems unneccesary. My questions have to do with how you wire this into the panel be it main or sub. I would assume you would simply hook it up to an existing breaker which would energize the hot bus to which that breaker is attached. I could always go the hillbilly route and run a bunch of extension cords off the generator but I envision a system where I roll out the generator, plug a cord from the generator to a transfer switch, kill the main breaker on my panel and then select those circuits which I deem necessary to run. Thanks for any input you might have on this.
I'm a general remo guy, not an electrician. Mine do it with the subpanel. I'll have to let the spark-tricians here answer the details, but I knew they wouold want the additional info. I do it the hillbilly way myself with a 6KW Onan that has seen a couple seasons use on the job.Reminds me - I need to freshen the fuel...
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How do you run your furnace fan (my primary objective) if you just run cords off the generator. By the way I hope you or nobody else took offense to the hillbilly reference as I am one.
No offense here. I have a boiler, not furnace, but I also ahe two wood stoves, so heat is not an issue. A few years ago here, we had a week long outage due to an ice storm. No power whatsoever for three days straight and then sporadic power for the rest of the week. A few miles down island there was no probelm so i was able to have power to work, but at home...We had all the heat we needed, I cut some blocks of ice from the pond with the chainsaw for the freezeer and refer. We use gas to cook. Since we are on well water, there was some minor inconvenience there. This was all before we had the generator.One guy here that has the generator tied in like you mention never listened to my advice to keep some gas handy, so he was in worse straights than we. He blindly assumed that the thing would run with no fuel, or that he could just buy fuel at the pump, even tho the pump runs on electricity too.
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This is the exact setup I just had installed by my electrician. I think the kit he installed was designed to run power into the panel through two 20amp breakers, but the more specific wiring details are beyond me.
As my 90 year old neighbor used to say, "be careful of that electricity- you cant see it, but it can still bite you!" I wonder how many times he got shocked 'back in the day'.......
For a setup like you are talking about you geta 4 to 8 circuit manual transfer switch.Each circuit is feed from the panel through the transfer switch and then to the load.The other side of the transfer switch connects to the generator.You manually operate the transfer switch so that the circuits are powered from the panel or the generator.Backfeeding the pannel from the generator is bit NO NO.One mistake and you can have dead bodies or fireworks.
I don't understand what you are saying here. If each circuit is fed from the panel thru the transfer switch and on to the load like you say then you have used both sides of the switch and there is no place to bring in the power from the generator. I really dont think this has to be that complicated. All you are doing here is replacing the incoming current that would come into the panel from the main line with current being produced by the generator. What I meant by backfeeding is that I would imagine that the electric co. repairman would appreciate you throwing the main breaker so that the alternative source of current that is being generated doesn't go upstream on a line that they think is dead.
Mine has a plate attached to it which prevents the generator infeed from being switched on unless the main breaker is switched off. That way, you can't accidentally send power back out the line and electrocute the repairmen.
The switch is multiple pole (as many as you have circuits) double throw. So the circuit is either connected to wire from the panel or to the generator."What I meant by backfeeding is that I would imagine that the electric co. repairman would appreciate you throwing the main breaker so that the alternative source of current that is being generated doesn't go upstream on a line that they think is dead. "Now with some panels and breakers you can get interlock brackets so that you can only have the breaker from the main OR the breaker from the generator closed, but not both.The problem that without this interlock or the transfer switch it is just too easy to screw it up and launch generator parts into space and/or the lineman off the pole.And don't forget that you will be doing this in less than perfect conditions. And you might not be the only one that has access to the panel (spouce, children, baby sitters, etc).For example.You have had an ice storm with 1/2 of ice on everything and the power is out.So you spend 2 hours out in the cold and dark chisling ice off the generator to get gas in it and get it started.The house is about 60 by this time, but you get the generator running and it start to warm up.But you are cold, tired, and sore from falling on the ice a dozen times.So you go to bad.You wake up at 3 AM because the generator stopped and it is now 50 in the house.You see the neighbors lights on. So you think that the power is resotred and go flip the main breaker on.Well if the power has been restored to your house then you generator is now launched into space if you are lucky. Otherwise it might catch on fire. The upside of that is that it will help melt the ice off the house.Or say the power has not been restored to your house yet. So in the morign you get up realize that the generator is sout of gas and so you restart it. Forgetting that you flipped the main breaker back on.Bye Bye lineman and hello jail.
I would even go so far as to contact the local utility company before doing anything. I believe that one of the greatest dangers to linemen is the ever-increasing number of backup generators. When they open a line and expect it to be dead, they get very angry when some HO turns on his generator and runs power back into the line.Les Barrett Quality Construction
Yes, you shouldn't energize the utility lines. Ever. And the simple solution is a double throw transfer siwtch that feeds your house from the utility OR the generator but never both and can never connect utility to generator.
BUT, if someone did backfeed through an extension cord AND leave their main breaker on, what happens. The electrons are neither malicious or smart enough to seek out linemen to the exclusion of every light bulb, fridge, TV and computer that was left on in your neighborhood. That large load is going to suck down the piddly wattage your generator can put on the transmission lines.
Again, don't do it! And a lineman is right to get uppity if there is even a tingle on the line. And in certain situations (one or two house downstream of a downed line, etc) the lineman IS at risk from backfeeding. But for all the generators out there, all the power failures and all the DIY electiricians, this would happen pretty often unless it took special circumstances to really endanger utility workers. David Thomas Overlooking Cook Inlet in Kenai, Alaska
I agree that the risk would probably be minimal and that's reassuring.
About ten years ago, a lineman with about 20 years of experience who worked for me in the Air Force was doing some work on the side on a farm. He got zapped, although he was one of the best exterior electricians I have known. His wife and two kids had a rough road ahead of them without him.
This is one area that should still be coordinated with the local power company first. The wiring of a transfer switch and backfeed issues are not that difficult; however, with the advent of so many generators at low prices, I worry that more than a few people will have grief over this issue in the coming years.Les Barrett Quality Construction
You mean something like this:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=11771&item=3866073204&rd=1
If this link works, it is one of the groups of generator listings on ebay..hmm, going up to 35k kw looks like.
http://business.listings.ebay.com/Industrial-Supply-MRO_Generators_W0QQfclZ3QQfcoZ1QQfromZR11QQsacatZ42906QQsocmdZListingItemList
jt8
Rather than going into a big description about how to do this, I googled around a bit and found two good links.
Popular Mechanics has a good step by step article on installation of a generator, manual transfer switch and subpanel at http://popularmechanics.com/home_improvement/home_improvement/1998/3/install_backup_generator/
I found another good article explaining the whole thing on the Porsche Rennlist, at http://members.rennlist.org/warren/generator.html
It seems to me that an automatic transfer switch would be better. I'd like the refrigerator, et al, to continue working if no one is at home.But we've been lucky. Much of central Ohio lost power for days and then got flooded. We didn't lose power for a second, and only a bit of water in the basement. Probably from the leaking supply line to the carriage that gets replace tomorrow...
Well the automatic transfer switch is only good if you have an auto start generator that is on NG or propane or diesel.And I think that those are out of the class that he is talking about.
Bill H alluded to it but didn't come right out with the cheqp answer.
"I would just want to power essentials such as furnace fan, fridge, freezer""
Assuming you have only a 3 kW generator or so, the cheap way is to simply put a 3 way switch in each line to the critical loads. This is what I did at my kid's houses, 3 kW generator. Common goes to the load (fridge, etc), one side to the CB inthe main panel, the other to the generator. Cheapest transfer switch there is. Over 16A total generator capability this still works, but you are not in code compliance for overcurrent. Only problem was when DIL called during one power outage when she was having "some of the girls" over for a scrapbooking session ('cause FIL had her house wired for an outage) and wanted a "quick rewire" for room lights vs. the freezer for 2 hours.
What I do for cheap on my own house is a padlock at the main 200 A breaker with a single red tagged key and switch and some custom bracket so that the key cannot be removed from the lock unless the breaker is off, that key is needed to unlock the 12 kW genertator control panel to start the generator and cannot be removed from the generator with the generator runnning - complies with wording of current codes. Time spent to figure out the locks, build rather intricate brackets, etc was more than a transfer switch would have cost, so I'm not going to provide any details, esp due to liability issues. Let us just say it involves some physical installation/removal barriers plus some plug in disconnects blocked by other physical barriers. The 9 YO grand-daughter would take at least 2 hours to figure out how to bypass it.
Caveat: 2 pairs of battery jumper cables will defeat ANY interlock switch in seconds.
>> The 9 YO grand-daughter would take at least 2 hours to figure out how to bypass it.Is she a power hacker? Sounds like a fun kid.
As to 'uncle', her uncle Kraig wrote the original usoft calculator program (still there after 3.1 on XP, with most his teenage errors!) Her 6 YO brother would only take 1/2 hour longer.
What's scary, is that the 4 YO brother would like figure out how to hack both of their efforts 10 minutes later, and the 2 YO in the family would likely set fire to it (and your computer) if you or I didn't kill power to every computer circuit in the house when he sees a lit screen!
By "power hacker" I was asking if she likes to hack power circuits, not computers.
put in a 35 kva unit for a customer in 99
its a 4 cyl ford diesel running off the 2 200 gal furnace fuel tanks so it has fresh fuel and an adequete supply (it uses 1 gal per hr)
the transfer panel is in the main line after the meter ,it has a guage on each leg to moniter the operating load + voltmeter
the whole unit is located in a seperate basement adjacent to the house but sealed fro the main house basement with a co2 detector wired to the upstairs in case of trouble
at the head of the stairs to the basement is a switch to turn on a set of emergency lights (battery powered) leading to the generator where you flick 1 switch to start the unit after which you manually transfer the power at the transfer panel
this customer lost his power i the ice storm of 98 for 2.5 weeks and his request was for a set up where he could run his whole house with out fiddling with a portable gen set gas cans etc & be able to have a bath after a max of three days
we found the larger used gen sets were reasonably priced compared to the smaller ones & also its harder to steal a 1500 lb unit thats bolted down
by putting it in the basement it can be fired up at -20 with no delay
this customer is very mechanically challenged and his wife more so
we made up a operating sheet to guide them and posted it at the emergency lights plus ran the both through it with out a problem
" since then we have been waiting for another big storm" so he can look like a genius
I assume this basement where the generator's located has some sort of ventilation to allow for both combustion air and for cooling air (and the exhaust pipe is routed outdoors.)For a permanent genset with an automatic transfer switch, it's a good idea to have both a block heater and a battery charger, to keep the engine warm and the battery ready to go.
I dident go into all the details at time if writing but yes it has all yopu asked about and more , it cost 22k cdn installed . I even had an engineer from National Research Counsel of Canada ask me about deigning a set-up for him after seeing this one in action , we are waiting to hear back on that one.