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Features to look for in stand alone generator
TomG-
Re: generator hook ups to utility equipment
My general contractor has an electrician who is familiar with this, as far as meeting the applicable codes. If you have some suggestions beyond that, I'd be very interested. I'm thinking of things the code doesn't deal with but that someone who has lived through an installation may have good ideas about. Are there things you wish you had done differently? Are there different types of subpanels or transfer switching that is more convenient or more flexible for changes down the road?
I will eventually be hooking up a grid-connected, Net Metering system (tie in wind power or PV cells to an inverter... sell excess back to utility when I'm not using all I generate, buy some from utility when my needs outstrip what I'm generating locally). Even though the controllers on the inverters for these systems automatically disconnect if utility power goes down, the electric company still wants the same manual disconnects they require for someone with a backup generator. Hopefully, what ever I put in now will still be usable when the net metering system goes online.
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Features to look for in stand alone generator
TomG- Yep, I recall seeing that some of the better RV generators run at 1800 rpm instead of 3600. Quieter I'm sure. And you still get the 60Hz as long as that's what it's designed for. I think that is my biggest gripe with PTO generators - I would have to run my tractor at PTO RPM for (possibly) days on end to make power. Not my idea of fun...
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Features to look for in stand alone generator
Steve: The lower RPM generators probably are quieter but also have much longer service lives. Maybe important for somebody like John who may get into the competitive power buz (That's just now cooking up here in Ontario). Yep, I thought I'd be getting a PTO generator when I first got the tractor. I made all sorts of brave pronouncements about not having a flock of small engine sitting around. Of course, that's exactly what I ended up with. The tractor does what it does well and so do the small engine toys. I understand big PTO backup generators for dairy farmers--bunch of grumpy cows and bad milk if the power goes down for long, and it takes a bunch to run a dairy operation. For emergency backup, I don't need everything on in the house at the same time, and I don't want to put a generator on the 3ph in the dead of stormy nights.
John: My hookup is a sub-panel that runs as a 60-amp branch circuit on the service panel. It has it's own 3-point main breakers for utility and the generator supply and mechanical linkage that prevents both mains from being on at the same time (3-point here is two hots and the neutral rather than tractors). I got a 60-amp panel with 24 branch circuit slots even though the generator puts out 22.5A/220V peak. I wired most of the original house on the backup panel even though I can't run it all. However, I can power most everything in the house by juggling branch circuits around.
My feed runs just over 100' with a 30' underground section. The underground runs through conduit so I can pull the wire by just digging at each end. I used 10-gauge (30A) line, which meets codes, but I also can't just hook up a larger generator. There probably is appreciable voltage drop over 100' and it may have been better to start with 8-gauge wire. I also could have used 1" rather than 3/4" conduit for the up sections.
I don't think my arrangement would work for you. I can't imagine a utility allowing surplus power to be fed to a grid by backfeeding it through service panels--could be wrong though. I expect they'll want transfer switches. The trouble with transfer switches is that they have to be rated at least as large as the utility service. A 200A transfer switch is very expensive, but I guess it could end up as a business write off.
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Features to look for in stand alone generator
I probably should point out my basic ignorance of small buz, or green power suppliers as they're called here before somebody else does. I might learn something. My impression is that this is low voltage generation that gets on to the grid by back feeding service transformers at higher voltages than supplied by the utility. Now that I think of it, I'd be surprised unless something more sophisticated than a meter is required.
This could be an interesting thing to do. With the way electrical rates are exploding around here, I can easily see that it might be cheaper to generate your own power by generator during 'gas wars' than to buy it from the utility. And of course, once it's in place solar, wind etc. is a whole lot cheaper and a lot greener than a gas generator. So, if it's cheaper for an individual, why not sell surplus to the utility?
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Features to look for in stand alone generator
Tom -
For more info on Net Metering (or Grid Interconnect systems as they are sometimes called) check out Home Power Magazine at the link I hope I attached below.
I would not be using my generator to feed back into the grid. That's too expensive. (Initially, it's for power outages from the grid and portable power needs.) What most Grid Interconnect systems do is synch the inverter (which takes the DC from you solar cells, windmill, or mini-hydro system) to the utility power. When you are generating more than you use, you run your meter backwards, and are selling power to the utility. When you need more than you generate, your meter runs forwards and you are buying from the utility (hence the term "Net Metering" .
The disadvantage of this system is you still have to pay to get the utility power installed at your site (unlike a completely off-the-grid system). The advantage is that you don't have to buy and maintain a bank of batteries... the utility grid acts as your battery. Another advantage is that you don't have to size your "Green" power system to handle your whole load. Surges for starting up motors, for example come from the grid, if needed. You can also start small and slowly build up to a system that meets all or most of your needs, as opposed to an off-grid system where you have to buy a good sized system from the start.
A lot of state in the US have Net Metering laws which require utilities to buy back this "green power". Vermont is one of these, and from what I've heard, most of the utilities are OK to work with on it. (In some states, the utilities make it a real hassle, even though the law requires them to do it).
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Features to look for in stand alone generator
Gee! Seems like I got it basically right. The concept of using the utility as a back up battery is a very appealing idea. I talked with a solar power consultant several years ago. He said that considering the costs of the equipment and electrical rates, people who already had utility power on the property would never get the investment back. He said his main business was for properties that would have to put in lengthy runs of private over-head lines to get utility power. But that was several years ago, the costs of solar panels etc. and electrical rates have changed radically since then. Sounds like maybe it’s time to revisit the idea.
I did sort of anticipate the need to sync the phases, and maybe some sort of voltage feedback to control current delivered to the utility. I can think of several ways to coordinate an inverter. More tricky with an engine, but I guess if gas became cheap enough, a generator could be used to charge batteries at a profit. Batteries would clean up dirty 12V DC nicely.
In terms of looking at generators; I recall that my township has a Kubota generator that I think is a 30A/220V peak generator. Don't know much about them except, like the tractor, it's orange and looks good. Might be something to check, considering the brand name.
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Features to look for in stand alone generator
I built my "house" 1000' off the road, completely without power. Although I had all the cable buried and was ready for NYSEG to turn me on, they took a couple of months to get there easment...then I got involved and had it in 2 weeks. (There's a lesson there...)
I have a cheap ($550) 5000W Generac with with 10HP Techumseh engine. I built the entire shell of the house with it. We ran all the tools, air compressor, well pump, etc. off it without any problems...until the last week of the building process. The air compressor started blowing the fuses on the generator, literally 2 days before we had the roof shingled.
It is very loud...but worked well. I had no problems running the 3/4HP pump 165 down. It is very difficult to start when cold...more or less impossible. Not electric start...and I'd highly recommend this, especially if you you hope your wife can get it going (at least my wife). (Although she did manage to start it up a few times when I was on the roof...always good for a hoot).
If spending the extra few hundred bucks won't cause financial pain, I'd buy something a little nicer. But at the time, I was building a house...
You also might want to look into the "transfer switches" that are avaiable to switch circuits from line to generator. No chance of backfeeding into the grid...which can win you somew nice fines from your power company, and possible kill someone. Home Depot has a box on the on-line site, complete with a heavy 240V cable and connectors, and outside "feed thru" panel, for som,ething like $179. I bought one and will install it as I wire the house.
Good luck.
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Features to look for in stand alone generator
Guess I've got several things to say. The first one could save somebody a bunch of money. Easements can be buggers to deal with. We almost had the power disconnected at our camp while we did a demolition and eventually put in a new service. A utility company site planner saved us. If we had disconnected, it would have cancelled an existing easement and would have required a new survey ($5,000CAN minimum) to get another. The order had to request a 'temporary disconnect pending service upgrade' to preserve the easement.
The second thing is that generator panels or transfer switches are very good things. Before we installed one, I used a 100A panel and a flock of receptacles on a piece of plywood that I had from my old sound buz. I added a stove receptacle and put twist-lock plugs in the well pump and furnace lines so I could run extension cords from the panel. The arrangement does 100% isolate the generator and utility equipment, but an inspector after we installed the generator panel didn't like the twist-locks. No pain though, the generator panel is much better. The old sound buz panel remains useful at building sites without power. The panel provides a number of 15A/120V outlets, some of which are GFI protected. It also provides a number of special receptacles that 220V equipment may use but may not be on a generator.
The last thing is that I guess a 1000' of service line would be overhead. We had one pole with a pole service on it put in. A pole contractor came with digging truck towing the pole trailer. He'd already put the panel, conduit, and even the ground plate already on the pole. He had the pole planted in under an hour. Those digging trucks are sure something--make tractor hydraulics look like it's barely there.
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Features to look for in stand alone generator
Just to complete the story...I have 44 acres of woods up on top of the hill...out in the sticks. The neighbor was a fellow from Texas (I'm in New York State)...NYSEG claimed to have tried to call him, send him mail, etc. 3 months of trying...no contact. I got his number and called him, he called me back, and 2 weeks later all was done. I'd think NYSEG would have just put the line over his property, as it was along the roadway, although maybe 40' in. He has 65 acres or so...and I have never seen him. No problems to do it the safe way.
My 1000' service is buried. 850' of primary buried in 4" conduit. I had my excavator dig the trench with his backhoe...through the woods...down the bank...it was quite a site. 13 hours later, some $650, he was done. I laid the 4" out next to the trench. We pulled the cable (this is big stuff, two 1" pieces) through the conduit as we built it, one piece at a time. It took us 3 hours to have it completely down. Yep, we were all amazed. At the end, we were pulling 800' of cable through the conduit, downhill, with our bare hands (two of us). We did lube the cable as we fed it in. I was VERY worried about this whole project but it worked great. All said and done, transformer vault, conduit, triplex to the house, meter, disconnect, trenching, and backfill was about $4500. I didn't want overhead...didn;t want to see it or worry about trees falling on it. As it turns out, if I did go overhead, a 80' white pine would have fallen across the lines this past Friday night during a nasty wind storm...I had to cut through it as it fell across my driveway. I did think of that burried line with smiles. Of course, if it ever fails the grin will change. But, since I am in 4" conduit, I can easily pull in another line as I remove the old...not too bad of a job.
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Features to look for in stand alone generator
That sounds like a good result. Even though I think of costs in $CAN, the cost seems much more reasonable than I would have thought. Texas is big. I hear it takes three months to get a phone call across the state.
Yes, underground is good. The utility 14KV line across the highway us has a bunch of splices in it from downed trees. We were here for one of them. It makes a real good fire in the bush, and it took the utility over two hours just to cut off the power. In the meantime, it was just a couple guys from the township throwing shovels of sand whenever the flames flared up. Real fortunate it was raining at the time.
I'm not sure, but it sounds like the buried line is 14KV line to a 220V transformer. It's good if the utility allows private work to run distribution lines. I'm pretty sure our utility would require that they do all work themselves, and their rates are pricey even compared to contractors.
I'm a little surprised you pulled cable through 800' of conduit. Usually I hear about 'pull-points' or what ever they're called every 200' or 300'. I suppose we'd be required to use them here, and such things do run up the costs. But as I mentioned, we'd start out with $5,000CAN min just for an easement survey. I wonder why government cutbacks only seem to get rid of the things I want, and every other government thing just keeps going up. Well, maybe it's just here or maybe just me. Anyway, glad you got the power and at what seems a bargain to me.
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