generator to run house and well

[alphadeltaromeo]

I don't have a problem with flipping the main breaker...is it the safest...nope, but works well as I use common (or rather uncommon these days) sense in operating the generator . I use what I have and it works fine.

Now, if one of you more well to do folk wants to donate to my auto-make-it-happen-transfer-switch...I certainly shant say no.

Andy

 

[mbwarner]

I am in your situation. We're in the country in an all-electric home. This is compounded by the fact that Pacific Power around here has been nick-named the Prince of Darkness, for good reason.

I run a 3/4 hp multi-stage pump that's down 60 feet, two refrigerators, a freezer, a Directv dish tuner, and some house lights with a 4000 watt 110/220 generator. 4000 is not enough to run the heat pump, water heater or the range, so I throw those breakers.

I work in a prison, so I have to address the possiblility that if there's an area wide power outage, I would be required to stay at work. I've written a startup and connection procedure and posted it on the wall by the panel, and labeled the critical breakers so my wife can start the system if need be.

Our garage was wired for 220 single phase, so I changed the receptacle nearest the main panel to match the 220 receptacle on generator, then made a double male 10 gauge four wire connecting cable, and put a 50 amp breaker on the garage 220 circuit in the main panel (circuit wiring is 10 gauge).

Have used it once so far, when power was out for 28 hours after a major wind storm.

Something to keep in mind is fuel. This was an area-wide power outage, so gas stations were shut down, too. You'll be depending on what's in your MV's and jerry cans for fuel, in that event--a good reason to keep diesel, not WMO in at least one M35, if you have a diesel generator. Since my generator is gas, I keep the M37 and M151 tanks 3/4+ full, with fuel stabilizer, and a couple of jerry cans. Gasoline stays fresher longer, the less air is in the container with it, and a full tank minimizes respiration and condensation as well.

I also drain and run dry the generator engine after use, so bad gas and varnish will not be an issue.

Hope this helps. Sorry to be so windy.

 

[Isaac-1]

Ok, first off 30KW is BIG for home use, I bought a 33KW Kohler Diesel generator for my elderly mother's house off government liquidation a few months ago (the price was right), she has a large 4,000+ SF all electric house with 3 central A/C units, well pump, electric stove/oven, etc. and does not want to think about load management. In the case of her house, it is possible for her to hit the 33KW capacity, however with just a little basic load management it is possible to have a near normal life in this energy budget (just don't try cooking with stove/oven while doing laundry, running all A/C's and taking hot showers (electric water heaters), etc. In contrast I opt for a much more minimalistic generator for my home (city water, gas heat, gas stove), currently a single 1,000 watt Honda generator, enough to run the fridge and a very small window air conditioner, I am seriously considering upgrading to a 3KW for my house, as the fridge and window A/C are pushing the limits on my little unit, still it is nice to know I can run it for 48 hours on 6 gallons of gasoline.

Now here a few generalities,One nice thing about diesels (at least those not prone to wet stacking) is a fairly linear fuel to output curve from 1/ 4 load to full load. (the above mentioned 33KW unit consumes just over 4 gal/hr at full load and just over 1 gal/hr at 1/4 load) Another advantage of diesel is the fuel cost can be 30-50% less than Natrual Gas or Propane units, also after a wide spread disaster it is likely to be easier to refuel than refuelling large propane tanks. Compared to gasoline, diesel is much safer to store, and if in a sealed drum can be stored for VERY long periods of time.

As to the 3 phase/single phase generator issue, do some research on the specific model you are considering, most 120/208 3 phase units can be reconnected for 120/240 single phase, however the majority of these will be limited to 2/3 of their total KW output in single phase connection, to keep full rated output a 3 phase 120/208 unit can run 3 balanced 120 volt legs, however this may need some special wiring (or just connect 2 legs to your standard hot legs of your home single phase, and use extension cords for the remaining 1/3), this would give you that same 2/3 useful power out of the unit, plus the other 1/3 through extension cords (or a dedicated 120 volt, single hot leg panel)

ike

p.s. many 120/240 home appliances (dryers, water heaters, Air conditioners, etc) will run on 2 legs of 120/208 3 phase, this allows the manufactuers to sell the same units to offices, etc. with 3 phase power, check to data plates to see if they read 208-230 instead of 230/240

 

[rat4spd]

mmmmmm.

 

[Wrench Wench]

God I hate being OCD. I just spent about 6 hours agonizing over this graphic. This is how I would like to wire up my nearly off-grid back woods dream home for 3-phase power with as large a generator as possible, figuring on getting multiple gennies for parts purposes and storing them all, spare parts machines and hooked up machines, in the basement, along with the extended-capacity fuel tank with a filler conduit up to the attached garage so I could fill it by simply hiring a home-delivery diesel tanker and running the hose into the garage. Can anyone think of a code snafu that would object to a basement diesel fuel tank on the order of 1500 gal with mechanical stirrers and stabilizers? (Yeah, a back of the napkin calculation shows that that would allow the entire house to operate for two solid months off nothing but the diesel, but I couldn't see doing that short of a collapse of civilization scenario.)

In an effort to balance the draw, each ~1500 sqft floor could have its own separate fluid pump for operating the radiant floor heating in the winter, A/C unit in the summer, and tankless water heater year round. The whole house would be super insulated to reduce the heating and cooling load and designed with passive solar in mind from the start, which I would hope to be able to extend that emergency back up power capacity to 4 months, or at least three.

Further, passive solar water heating should further reduce year round heating load, and both PV solar and wind turbines (hand-built off surplus military generators if I could figure out the intricacies of the CVT) would further extend the home's off-grid power capacity to, hopefully, the foreseeable future.

I think the best way to go is the shotgun approach. Putting all your eggs in one basket is foolish, whether that basket is the grid, diesel, solar PV, whathaveyou.

I haven't yet done any kind of power budget calculations, so it may just be completely impractical to have any auxiliary generator fuel tank at all, regardless of steps taken to keep the fuel fresh, if the house's maximum power draw is kept so low and the powerscape is dotted with PV and wind and passive solar, not to mention grid intertie.

Speaking of grid intertie, a thought occurred to me when I was looking at a large whole-house NG/LP genset in the latest Menard's circular... If the grid is down over a large enough area, wouldn't that include the NG pumping stations?

http://mama.indstate.edu/users/garrett/Projects/Semicircle/3-Phase Balanced Breaker Boxes.png

 

[swbradley1]

Major code/safety fail for the reason of someone forgitting to flip the main and then backfeedin to the transformer killin' the lineman tryin' to fix the problem in the first place.

I use a three way transfer switch to tie into the panel.

Adrianspeeder

That must be one heck of a throw on that switch considering where you are now.

 

[5tonpuller]

Took a course in generation about 3 years ago. It was given by onan. The main thing to remember is that when things that run by a motor, when it starts it can take 3-4 times the running watts to start for the first 1-3 seconds. IF the power is not there it does get ugly and dark.

My $0.05 worth.
Matt

 

[Isaac-1]

Wrench Wench, one potential problem leaps out at me on your wiring diagram, namely is 3 phase power available from the power company at your location. In many residential / rural areas 3 phase not available, and in many areas even if it is, the power companies will not connect it to a residential service without a good reason.


Ike

 

[Speddmon]

Wrench Wench, one potential problem leaps out at me on your wiring diagram, namely is 3 phase power available from the power company at your location. In many residential / rural areas 3 phase not available, and in many areas even if it is, the power companies will not connect it to a residential service without a good reason.

Ike, you are absolutely correct that in most cases the utilities will not connect 3 phase power to residences. However 3 phase power is available in those residential areas, they just won't hook it up. The utilities always transmit in 3 phase, just because it's easier. If you look down the street in most suburban areas where each house has it's own transformer on a pole, you'll notice that there are 4 high voltage lines going down the street...the three on the top are usually the 3 phase "legs" and the one below them us typically the ground. If you follow them out long enough, you can see that they'll take a few houses from one "leg" and then switch to another "leg" for a few more houses and so on. This is done for balance.

p.s. many 120/240 home appliances (dryers, water heaters, Air conditioners, etc) will run on 2 legs of 120/208 3 phase, this allows the manufactuers to sell the same units to offices, etc. with 3 phase power, check to data plates to see if they read 208-230 instead of 230/240

While most of these appliances will work on one phase of 208 3 phase, keep in mind that if the device has a control transformer (like all a/c units). The control transformer is set up to deliver the proper control voltage when it's fed with 240 volts and not 208 volts. In order to run on 208 you'll need to change the wiring on the control transformer, most have a provision for this.

As to the original post and many subsequent reply's. 30KW is way too big for your average home. Unless you are made of money, unlike the vast majority of us, it's just overkill. As an industrial electrician, I can safely say that the load calculations most generator salesmen want you to use are going to be overkill as well. Remember, they want to sell you the biggest baddest generator they can, and you probably don't need it. While I agree that you need to size your generator properly, you do not need to add the load of every motor operated device in your home (Fridge's, A/C units, pumps and such) and multiply by 6 times (that's the general standard, starting current is about 6 times full load running current for a short period). Rather, I would take the largest device you have, usually your a/c and multiply it times 6 (if you feel safer with some overkill multiply it times 8 or 10). Remember, that inrush current is based off of "locked rotor amps" meaning starting from a dead stop. Unless your a/c unit is 20 years old and normally draws near full load current all the time, you're probably not going to see that 6 times figure at start-up (my 3 ton 2 stage geothermal heat pump only pulled 75.6 amps at inrush out of a rated 100.2 inrush amps). Full load current is the most that that motor will pull, under fully loaded conditions, your a/c compressors and condenser fans do not usually draw anywhere near full load current.

I say, use your largest device because of the highly unlikely situation of all of these devices starting at the same time. They are going to cycle on and off as needed. The only time when they could possibly start at the same time is if the power has been out for several hours and the refrigerators and freezers have warmed up to the point that they need to start as soon as power is applied, and your house has gotten too warm and the a/c needs to cycle right away as well. The worst that can happen is that you may load the generator a bit too much and bog it down some or possibly stall it out. If we're talking military sets like the MEP-003a, I would safely say that they probably have a starting capacity of about 300% of their full KW rating (for the MEP-003a that would be about 150 amps at 240 volts). Meaning they will produce about 30KW for a very short period of time, enough to start a motor. That's the reason I feel I have a more than adequate generator for my home using my MEP-003a.

As for lights and other appliances, use your head and think about this for a minute...to pull just 1KW of lighting load you'll have to have 16, 60 watt bulbs burning all at the same time to reach just 960 watts, that's less than 1kw. How many of us still use regular light bulbs any more, I use all CFL's. TV's and other things are very low power consumption as well. Your biggest loading concerns are the motor driven devices.

 

[Wrench Wench]

What about so-called soft-start motor controllers? Any more, those are getting included in HVAC plants just because it means the motor is quietter on start-up, but it also extends the life of all of the components over just throwing a relay and slamming 50 A at 208/240 VAC right into the motor. It's hard on the electricals. It's hard on the mechanicals.

A soft-start is just a PWM motor controller that starts with a low duty cycle, just enough to get the mechanicals (pumps, fans, compressors, etc) moving very slowly. Then, the duty cycle grows over the course of time, either many seconds, or even minutes for large loads. That would thoroughly aleviate the start-up power spike and even the need for power factor correction, if I'm not mistaken. If the PWN controller goes to 100% duty cycle, then the relay can go ahead and trip for full load so the PWN itself is only really used for soft-start, rather than run. But lots of soft-start controllers are also used in HVAC for multi-zone climate control so one zone can take lots of air volume while another zone takes a little air volume off the same trunk plant. I'd like to use it to vary the radiant floor heating flow between individual rooms.

Anybody have eny experience with soft-start running off generators? The PWM controllers shouldn't be that problematic. if you have skillz in embedded electronics. Chip makers like Parallax have lots of parts with PWM generators for motor controllers, et al., and there are oodles of 240 VAC solid state relays out there for cheap.

As for getting residential 3-phase, I've been told farmers do it all the time. They get 3P for their farm equipment and the electric company just extends it right on into the home, no problem. I can see getting/conning the electric company to install 3P for the garage and then just extending it on up the hill into my home.

If you're really paranoid about getting and keeping 3P in your home, you could try one of these:

Buy our MEPEM 30kVA 3 Phase 208 4 Wire Input/Output Uninterruptible Power Supply by Lightolier Inc at GoodMart.com

But then, they cost as much as the rest of the house itself.

 

[Speddmon]

Wrench Wench,
You are right about the farmers getting 3 phase installed and you could probably con the utility into putting 3 phase into your garage, but I doubt that you'll like the price. By conning them into it you're probably going to have to convince them you are running a business, and the electric rates for companies is usually considerable higher than residential rates.

As far as the HVAC goes. A much cheaper and more practical alternative to a soft start is to put what the HVAC tech's call a "Hard Start" kit in it. It's nothing more than a start capacitor and a potential relay installed along with the running capacitor that's already there. What it does is provides considerably more starting torque for the single phase motor, thereby reducing the inrush and not generating as much heat in the windings and saving the equipment in the long run. It will, a lot of the time, even make an old worn out ac compressor start when it is thought to be dead. If you talk to an HVAC tech about it, don't let them tell you that they are only for older units. I installed my own in my brand new $6000 geothermal heat pump and dropped the inrush current down to about 46 amps from about 75 amps before. Cost of the components was about $25 and the years that it should add to the compressors life makes it well worth it.

 

[rat4spd]

For the most part, those of you considering a 15KW or even 30KW mil genset, you are getting WAY too much. An el-cheapo, sure, you get about what you pay for, but the starting capabilities of mil sets is huge. The MEP003 at 10 KW is conservatively rated, actually puts out around 14KW, and will start 20KW.

 

[swbradley1]

If you're really paranoid about getting and keeping 3P in your home, you could try one of these:

Buy our MEPEM 30kVA 3 Phase 208 4 Wire Input/Output Uninterruptible Power Supply by Lightolier Inc at GoodMart.com

But then, they cost as much as the rest of the house itself.

That's a little one. I had one that was 50KVA just to run one small room at a previous job. Of course the battery room was just as big.......

 

[Wild Horse Hans]

Yea, 30k is way overkill. During the ice storm we lost power for 7 days. I ran the entire house on a 4700w gen set up on the front porch. It was a bit loud and it had a small gastank on it so I got about 8 hours of run time, but it ran everything in the house including the heater.
I want to pick up a 10k as I never want to have to go through that mess ever again. I had to borrow the gen from a friend so we were dark for 3 days until he got power and let me use it.
Hans

 

[steelandcanvas]

I am in your situation. We're in the country in an all-electric home. This is compounded by the fact that Pacific Power around here has been nick-named the Prince of Darkness, for good reason.

I run a 3/4 hp multi-stage pump that's down 60 feet, two refrigerators, a freezer, a Directv dish tuner, and some house lights with a 4000 watt 110/220 generator. 4000 is not enough to run the heat pump, water heater or the range, so I throw those breakers.

I work in a prison, so I have to address the possiblility that if there's an area wide power outage, I would be required to stay at work. I've written a startup and connection procedure and posted it on the wall by the panel, and labeled the critical breakers so my wife can start the system if need be.

Our garage was wired for 220 single phase, so I changed the receptacle nearest the main panel to match the 220 receptacle on generator, then made a double male 10 gauge four wire connecting cable, and put a 50 amp breaker on the garage 220 circuit in the main panel (circuit wiring is 10 gauge).

Have used it once so far, when power was out for 28 hours after a major wind storm.

Something to keep in mind is fuel. This was an area-wide power outage, so gas stations were shut down, too. You'll be depending on what's in your MV's and jerry cans for fuel, in that event--a good reason to keep diesel, not WMO in at least one M35, if you have a diesel generator. Since my generator is gas, I keep the M37 and M151 tanks 3/4+ full, with fuel stabilizer, and a couple of jerry cans. Gasoline stays fresher longer, the less air is in the container with it, and a full tank minimizes respiration and condensation as well.

I also drain and run dry the generator engine after use, so bad gas and varnish will not be an issue.

Hope this helps. Sorry to be so windy.

How do you disconnect from the utility, when using your genset? With your connection cord, isn't one of the male ends hot??

 

[NDT]

National Elecrtic Code calls for a "transfer switch" to disconnect from utility and connect your house load to the genset. I was looking online today for one of these, I need a 100 amp unit, but these things seem to be way overpriced at $700+ . . . Where are the bargains? I need an outdoor one.

 

[Speddmon]

Yes, the NEC states you need a transfer switch. And that is by far the safest way to do it. However you can get by with just pulling (turning off) your main breaker in the panel, before you hook up the generator. If you have the generator tied into a sub panel, make sure you pull the main breaker in the main panel, again, before you hook up the generator. This will isolate you from the utility. But by doing it this way you'll not know when the power comes back on unless you have neighbors close by, or you go out and test the incoming lines with a volt meter. If you're not comfortable doing it this way, by all means buy a transfer switch...manual ones can be had rather inexpensivly, I would check on e-gay for one.

 

[firebuilder]

Shameless self promotion, but CAT makes a wide range of standby, prime power, and continuous usage gensets in single- and 3-phase, diesel or gas, starting at about 12 ekW.

Cat Generator Sets - Diesel, Natural Gas, Bio-Fuel & Alternative Fuel

 

[littlebob]

How do you disconnect from the utility, when using your genset? With your connection cord, isn't one of the male ends hot??

I have an old classmate that does Electriacal for a living. He said he can probably get the 10K 3PH unit on the M51 shelter trailer to run our small house. thanks for reminding me before Hurricane season gets here! As far
unpluging the utility you can pull the meter, You have to have them come and put a new tag on afterwards and give them a good ass chewing if they give
you any crap about removing the meter when they couldn't provide power

 

[mangus580]

National Elecrtic Code calls for a "transfer switch" to disconnect from utility and connect your house load to the genset. I was looking online today for one of these, I need a 100 amp unit, but these things seem to be way overpriced at $700+ . . . Where are the bargains? I need an outdoor one.

I presume you are talking automatic at that price??

I like NoOutage Home they have great prices on manual switches...