Propane Generator and Transfer Switch

I'm considering having a 16 kw generator installed and I'd like to know what to expect when the generator and transfer switch is installed and hooked up. For example to what is the main power coming from the transfer switch hooked up into my breaker panel? What happens to the breakers of the different circuits that selected for emergency operation. Do I give up any of the current open breaker spots I have. The Guardian unit I am looking at says it operates at 76 decibels. I don't know what equivalent noise level that is. At the moment I am planning to have it placed directly on the other side of the playroom wall as that is where the main breaker panel is located. I also have a suitable spot about 20 feet away from the house if the noise would be a problem. I'd like to be able to observe the process with some sort of understanding. Thanks for any input or other comments about the actual hooking up.
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John,
With a generator that size, there are actually two types of transfer switch you could use.
The type you'll see at Home Despot, which is the cheaper of the two, has individual switches for each circuit (typically anywhere from 4 to 12 circuits). Each switch can be thrown one way to power its circuit from the main panel, or the other way to power it from the generator. The advantage of this type of switch is you can select the circuits in advance to make sure you don't overload the generator. The downside is versatility - only the circuits wired to the switch can be generator-powered.
The alternative is a single large switch that switches the entire feed for your breaker panel between utility and generator power. These switches cost more, and offer more versatility - you can power anything in the house from the generator, subject of course to its power output limit. That's also the downside: if you're not careful, you can easily overload the generator by trying to power too many things.
If you Google "noise level decibels" you'll find some info on the web about how loud 76 dB is. One page I found puts it about halfway between "busy street traffic" at 70 and "vacuum cleaner" at 80.
Eric Law

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Ask whoever is going to install it if you can see one of his previous installations. It will sound like a lawnmower going all night. You will be extremely popular with your neighbors, especially those still in the dark. There is one a half mile away from me, and in my driveway it is louder than my Honda.
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Toller wrote:

You should hear how loud the Home Depot version Generac (looks like the good one but isn't) units are. I helped my buddy put his in and I know someone else who has one. When we started my buddies it felt like you were standing next to a jet engine or in a room with 1,000 HP motors. I can't imagine anyone living within a block of one putting up with it.
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I live just west of Ballimer (Baltimore - the city that slurs). We just experienced the first of the usual Fall-Winter power outages. A few years ago, we had no electricity for 6 days. the usual outages last 1 to 3 days. We were considering a generator until we heard one up close. At 100 to 150 feet they don't sound that loud, but if you are in the house, you have trouble hearing what people are saying.
Dick
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I installed a Generac permanent generator with transfer switch a year ago after facing two extended power outages here. The Generac design for the transfer switch requires a dual breaker to be installed in your main panel which passes power to the transfer switch. The transfer switch then subdivides this feed into 12 circuits, each of which has its' own breaker in the transfer switch panel. These 12 circuits are the ones were are supported during a power outage, and are literally disconnected from their current 12 breakers in your main panel and connected into the corresponding 12 breakers in your new transfer switch. You actually "recover" 12 breaker positions in your main panel since the 12 breakers could be reused (assuming you have enough total house capacity and panel capacity to do so). The feeds from each of the 12 house circuits are attached to 12 conductors which Generac supplies using wire nuts. The entire installation process is described in a video which can be viewed on the web, or on a DVD which Generac also provides.
The noise level of the Generac is not terribly loud, but similar to a lawn mower / tractor of comparable capacity when running full load. The weekly test mode for 12 minutes of run time runs unloaded at a lower noise level. To those of us who have subsequently lived with the generator during an outage, the sound of the generator is sweet music. It is the silence which occurs when it is not running but needed that I would call deafening! I would advise to simply put the generator away from the major sleeping areas of the house, and non fret about it. The noise level inside the house is totally moderate. My neighbors on both sides have Generacs, and there have been literally several thousand sold in my area in the last year as a result of a freak October ice storm which took out power for some people up to nearly 3 weeks.
I would also suggest you seriously evaluate your total electrical demand since 16KW is too much power for many homes unless you want to run air conditioning, electric stove, or other big power users. The Generac smaller models produce considerably more efficient and less expensive electricity when used near their peak capacity, versus running a 16y KW generator at half load. Not only do the operating costs drop, but the cost of the unit itself is considerably less.
Good luck and let me know if I can help you further, Smarty
panel.
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Re Re: Propane Generator and Transfer Switch:

Good points and good advice. I might also suggest that if possible build a small shed for the generator. The shed will lower the noise level considerably. Note that I wrote "build". A small commercial shed won't do unless you make a lot of modifications for ventilation.
When I installed my generator ( a loud cheap brand ) 15-years ago I designed/built a small shed as it was cheaper and easier than having to modify a commercial model. It works well to this day.
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Honda has some of the quietest units and publishes db ratings and comparisons. 87 is alot and the low frequency of the sound travels through walls, it rumbles as its a large motor. The lower the frequency, the longer the wave and the more difficulty you have in stopping it. You wont like it. Honda has portables you dont really notice at 15ft or so, or be annoyed. You will have a monthly test mode which will consume a noticable amount of gas. If outages are rare consider a portable you wheel out and plug into a transfer swtch and manualy control. How often does the power go out and for how long, If its once a year for a few hours a portable is best, like a Tri Fuel Honda. The Generac is a 3600 rpm unit with maybe 2-3000 hr life, An inverter series Honda or yamaha run easy at 1600-1800 rpm can easily last 10,000 hours, rpm is load dependant unlike what you are looking at, unless their design has changed.
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ransley wrote:
...

" ... rpm is load dependent ... "
Should only be slightly. Exactly what do you mean?
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Most generators you buy are 1800 or 3600 rpm gas or diesel, under 15000 w or so gas, they are usualy 3600 rpm Honda and Yamaha have an Inverter series that only run at the rpm needed to generate the power needed, the generator is built into the motor on the small units. They also provide clean power or sign wave, safe for all electronics. If for example you use the Honda 3000w Inverter unit to generate a few hundred watts it may only run at 900 rpm, this not only saves gas but increases the life of the motor dramaticly. It is believed that cutting an engines rpm in half increases its life 400%,at 900 rpm it could last in theory 100,000 hours. 3600 rpm units last from 300-3000 hrs depending on who made them and how heavily you load them, but Honda 2000 EU are known to last, some say they have gotten 12000 hrs from running light loads on campers. The Generac is 3600 rpm even if it produces no power, the Inverter units probably idle at 5-600 rpm, keeping an easy load it might only run 1800 rpm and run 15 hrs on a gallon of gas where the 3600 rpm units operate differently, Hondas site explains it better and shows the increased fuel efficency of their Inverter units. They cost maybe 3x that of the competition but you get what you pay for, alt.energy.homepower is where you will get better answers from alot of off - grid folks
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ransley wrote:

Ah. So the generator is not actually an AC generator, but probably a DC generator with an inverter or other electronics to generate the 60Hz AC? A normal AC generator would only produce 60Hz if it was running at the design RPM of 1800 or 3600. Clever idea. Probably now economical because of spill over from photovoltaic industry.
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Right , if regular gens deviate from the design speed they dont produce 120v 60 hz, cheap gens swing up to 20v and the coresponding hz, so its common on a 350$ unit to go to 100v 50 hz under full load and swing so much they damage anything with sensitive electronics, like a microwave ot tv, A friend bought a new 550 unit and in 5 minutes it blew his new tv, only later he found out it was never set right and was outputting 160v, probably running at 4000 rpm or so. The inverter units are the way to go.
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That's right. The generator just has to generate enough power at a suitable voltage, and the inverter electronics synthesizes 60 Hz sine waves no matter what speed the engine is running.
I'd guess the "generator" is actually a multiphase alternator whose output is rectified to DC, for the same reason your car uses an alternator instead of a DC generator: simple construction, no brushes to wear.

And large inverters used on boats, long-haul trucks, etc.
    Dave
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Snarty, Thanks for the in-depth reply.and the capacity info. John
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I just installed a 12 kw B&S generator at our cottage. It has a 60 amp circuit breaker and has ample power for our needs. Even runs a couple of base board heaters. In Canada you need a seperate house entry switch to turn off the Hydro.
We have a 200 amp service & therefor required a 200 amp transfer switch. It handles the whole cottage. It didn't make sense to me to put in a seperate fuse panel just for the generator, so we switch the whole thing.
hydro comes into house entry switch and then goes to transfer switch generator goes to transfer switch output of transfer switch runs to main breaker panel
We use LP to run it and it starts automatically. (We have a lot of power outages)
76 db is very noisy. Your neighbours will love you. Ours is 65 db at 20 ft I suggest you look for another brand. This is what I bought. http://www.homegeneratorsystems.com/products/empower/12kw/specs.cfm#specs
Bob
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Here's some descriptions of 76 decibels...
1 - Now for your heating and air conditioning system. The part of the central air conditioner that sits outside is the condenser. There are loud condensers and there are quiet condensers. A loud one will annoy you (and your neighbors). Again, the quiet ones are usually the most efficient. Choose an ENERGY STAR qualified system with a nominal sound level of 76 decibels (db) or less, and talk to your contractor about locating the condensing unit where it will be the most unobtrusive - sonically and visually. Make sure walls or landscaping features do not block airflow to the unit because that would reduce its efficiency.
2 - Directly in front of us is a big steel street plate covering a hole. When an MTA bus drives over it, it emits a nasty whap. Schiff whips out the meter: 92 decibels. Worse, it's pitched around 500 hertz. High-frequency notes like that hit us hard, because our ears are optimized to pick them up (human speech is in the 500-to-2,000- hertz range). Deep notes aren't as irritating, even when they're louder. When an SUV drives by with bass that shakes our chests, it's a healthy 76 decibels. But it's not as annoying as my cell phone, which is only 73 decibels.
3 - At Allapattah Comstock Park, seventeen-year-old Noesterlin Sanchez didn't seem to mind or even notice the rusty swing set's high-pitch creak. Swinging away on a Monday afternoon, Sanchez's thirteen-year- old twin cousins, Mella and Mello De la Cruz, cranked the swings up to a blackboard-scratching 76 decibels. That number shot to 86 as an ambulance screamed by, then a lawn mower wheezed to life, and finally a jet passed so low overhead it looked like it might play chicken with a city bus on NW 28th Street.
4 - Noise exposure levels for tilesetters
University of Washington researchers have been measuring the noise exposures of construction workers. Among tilesetters, we found: - the average level was 76 decibels across a full work shift - one-fifth of work shifts were above the 8-hour limit of 85 decibels - nearly one-third of work shifts had short periods of extremely high levels (above 115 decibels)
5 - Freeway at 50 ft from pavement edge 10 a.m. . . . 76 dB Living room music . . . 76 dB
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wrote:
[snip]

The outdoor unit contains a condenser, fan, and compressor. The compressor makes most of the noise.
[snip]
--
88 days until the winter solstice celebration

Mark Lloyd
  Click to see the full signature.
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