Home Generators (or How DTE Energy Ruined My Holidays)

We are among the thousands without power in the northeast. Day four actually, and we've decided to look into generators so that next year's New Year's doesn't involve fears of frozen pipes bursting and hypothermic babies and cats. At the very least we just need enough juice to run the furnace blower, but if we're going to lay down the cash I'd like to know what it would take to get a little more power ... like enough to run a fridge, router, laptop and lightbulb. I know nothing about this sort of thing, but figure there are more than a few experts out there so I call out to the wisdom of the mob. What am I looking for? How difficult is the wiring? What will it cost me? On the extreme edge, what would it take to get off the grid entirely? (And on a side note, thanks to DTE Energy for telling us we had power when we didn't, for losing the ticket for our neighborhood, for telling us it would be back every single day when it wasn't, and for the helpful DTE representative who warned us that our pipes might burst. Thanks.)

Comments

tips

[fyngyrz]

At a minimum, you need:

• A fair amount of 14- or 12-gauge wire (wire is expensive... go measure)
  • wire from generator switch breaker to each device
  • wire from generator to generator switch (needs to be underground / outdoors rated)
  • wire from main service to generator switch
  • instructions are generally with generator switch - study hard. Errors can be disastrous
• A 15A or 20A socket at each power location (fridge, furnace)
• A manual generator to line switch ($150 or so on Ebay)
• A generator. I suggest MINIMUM 3500 watts
  Even though a furnace doesn't pull a lot when running, at the time that the blower starts up, there can be a VERY large startup current. The fridge the same, to a lesser extent.
• A shed -- you can't put a gas generator indoors, generally speaking - very dangerous
• I strongly suggest a strong table to mount the generator on for maintenance
• Some way to bolt the table down, and bolt the generator to the table
• High temperature exhaust hose for the generator (actually kind of difficult to come by)
• high-temperature pass through for exhaust to go thru shed wall - hot!

You can get a lot fancier than this, but this will function perfectly as long as you are there to do the switching soon enough after power fails that your building doesn't get too close to pipe-freeze (I wouldn't want to go below 40 degrees f, pipes are often in walls that are cooler than the rest of the house.)

If that won't do, you're looking at an auto-start system with an auto-generator switchover, and the only thing I can tell you about that is prepare your wallet for deep excavation.

Re:tips

[Anonymous Coward]

No way man - you don't need anything nearly that complicated. Since you're just covering an occasional power outage, you don't need anything permanent. Just put the generator outdoors, and run a long extension cord (or a few) inside.

Make sure the generator is in a locked location, or at least chained down. They have a tendency to sprout legs during emergencies.

If you want something permanently in place, you need an electrician, and no less. Because you need a huge On-Off-On lever switch to ensure you never attempt to power the house from both the generator and grid simultaneously.

Re:tips

[MightyMartian]

I just ran heavy (15amp rated) extension cords this year when our power went out. I'm wiring up my shed this spring, so I'll already have a back ho out digging the ditch to run the underground wire, so I'm going to run a spare three pole 10-gauge direct burial (will cost some bucks) along with the main run out to the shed. I'll wire up a few outlets around my house that connect specifically to the generator (which is an el-cheapo Walmart 3500 watt gas unit), because a) the generator ain't big enough to power my panel and b) to do so in my neck of the woods requires a cut off so you're not rendering your incoming power line hot.

A bit of advice I got when I bought the generator was that you don't need to run your fridge and freezer all the time, providing you open them infrequently. Every few hours just plug them in, let the compressors bring the temperature down, and then unplug them. At the very least, don't keep the fridge door open while you ponder whether to use hot mustard or not. As you say, many electrical devices that don't draw a lot of power while in use can draw a lot of power at startup (cranking is I think the technical name). Even TVs can draw considerable juice when you first turn them on, so you probably will not want to put all your devices and appliances on a power bar and then flip the switch, but rather turn on each device one at a time.

Another thing my manual makes very clear is that the generator should be properly grounded. I didn't do that this year, but as I said, when I wire up my shed, I'm going to have to use a grounding rod anyways (since I'm putting in a subpanel) so I'll just bond the generator to that. 20 amps and 120 volts is enough to cook you good in the right circumstances.

Re:tips

[Muad'Dave]

I wouldn't go the route of running all that extra wire. They sell 6 circuit generator switches for that exact purpose - you move the desired circuits from your main panel into this little box, and hook you generator to it via a standard twistlock connector on a flexible cord. When the power fails, roll the genny to the panel, plug it in, fire it up, and flip the switch. If you know evil weather is coming, pre-stage the genny and cover it with a barbecue grill cover until you have to fire it up. Once it's hot, rain and snow won't bother it.

Re:tips

[InlawBiker]

I've gone through enough power outages to do what you're wanting. This is a good list but I can simplify it a bit.

1. You'll need a transfer switch to connect your generator into your home's wiring. It is possible (but probably illegal) to back-feed your generator into your home. Improper backfeeding will send power back up the line, creating a danger to the line workers.

A transfer switch essentially allows your generator to become the power source to your home while cutting off your city power. You can do this yourself or hire an electrician, it's not real expensive. Here's a simple diagram.

2. Next figure out what size generator to get. There are many calculators out there to guide you. Essentially you add up the wattage of each appliance and buy a generator with about 20% extra.

An example, I have a 3000w generator, it runs 2 fridges, the gas furnace fan, most of the lights, maybe some music. It's very quiet and luggable. We turn off lights when not in use and leave the TV off, but could probably run it.

Depending on how close your neighbors are you might want to check the decibel level of your gen-set. The cheapo ones work great but are very loud.

Re:tips

[hardie]

"I know nothing about this sort of thing.."
I strongly advise having someone who does do the installation.
You *must* have a switch that disconnects your house from your service drop. This is not a small switch--typical would be a 100A disconnect. If you don't, your generator will feed the service and present a huge danger to the people trying to restore your power. Ours allows the house to be powered off of either the generator or the utility, with no way for the utility and generator to be connected.

We bought an 8kW generator when we moved to Maine five years ago. My first thought was to buy a larger unit, but there's a problem with this idea. Compare fuel consumption fully loaded and at half load. IIRC, half load still consumes about 3/4 of the full load fuel. Generators become much less efficient at low loads--this means that you want to size it right, not oversize it. Running a generator isn't cheap.

I added up what we would typically have running and I think I came up with 4 or 5 kW. Bumping it up to 8kW seemed reasonable. Everything runs fine except the microwave (which acts browned out), and I don't use my plasma cutter or arc welder when we're on generator.

Steve

Re:tips

[Harik]

Indeed. A 200 amp manual transfer switch can be found for $400 online. This gives you the ability to have a male plug coming out of the transfer switch that can never be powered by the utility - if it's connected, the mains are disconnected.

They usually come in the form of a breaker box. Installation isn't trivial, but it's not exceptionally difficult. First, identify what circuits are "must have" during a blackout. This would be:

• furnace blower, HVAC (in hot climates like florida)
• food storage (fridge, freezer, deep freeze)
• lighting
• well pump if you don't have city water,
• pipe heaters for those of you up north
• food prep - electric ranges are probably too much load, but you may be able to run a small or midsize microwave. If you have a gas stove with electric controls, power it as well.
• a few marked outlets specifically as on generator, so you can charge phones/run your laptop/listen to the radio/whatever.

Next, wire in your transfer switch to your main breaker box. Some go on their own 200amp breaker, others may be wired directly to the rails. TURN OFF YOUR MAIN BREAKER BEFORE WORKING ON YOUR SYSTEM. Read the manual to your transfer switch carefully, incorrect installation can be extremely dangerous.

Once the new subpanel is installed, you can move your protected circuits to it one-by-one. With mains power off, remove the breaker from your main panel, put it in the subpanel, and move the associated wires. Don't forget to replace the hole in your main panel with a blank, or you'll have a safety hazard. Once all the circuits are transferred, make a male plug for the AC input to the transfer switch that uses a heavy gauge connector (200a for a 200a switch). You may be able to skimp there as long as your extension cord is rated above the BREAKER on your generator. Not the rated power, but what it actually trips at.

With all that, a startup tip would be to power up the generator, turn OFF all the circuits in the subpanel, switch the input to the generator, and power them up one by one.

And please PLEASE check local code before trying this yourself. I have left things out that vary from state to state, and some other details that you have to know before trying something like this (what gauge wire to use between the main panel and your transfer switch, for instance). If you have a friend who is a LICENSED electrician you should definitely ask them to look over your plan, and inspect your final work before you use it.

Finally, not every locale allows owner-improvements to electrical systems, and you may have to use a licensed contractor.

Re:tips

[xous]

This shouldn't even be suggested. Buy a bloody ATS. http://en.wikipedia.org/wiki/Transfer_switch

Pipes bursting

[Shimmer]

Might be best to turn off the water entirely and drain the pipes rather than risk a burst.

I just finished something similar

[Muad'Dave]

I just built a new house, and had a 20kW Generac air-cooled generator installed along with a 200A automatic transfer switch and buried 1,000 gallon propane tank. It can run on propane or natural gas, and is manly enough to run my whole house. I have heat pumps with backup propane furnaces. The outside units are small enough so that I do not have to sequence the startup of the compressors, but I could do that if necessary (and may anyway). It self-tests once a week. All told, minus the tank (since many/most of you will have NG service), about $8,000 installed and tested. Well worth it for totally automatic, no-worries switchover even if we're away.

Natural gas backup generator

[Wonko the Sane]

Bottom line: Permanent home backup generators can be purchased for $3000 - $6000 + installation labor.

If you have natural gas available then I highly recommend using it for your backup generator, since outages are very rare and you won't ever need to worry about storing fuel.

If you house is like most, then your incoming service is 100 amp/220 split-phase. This means that a ~22 KW generator would give you 100% backup, but really most people don't use more than 80% of their service, so this setup should provide full capacity backup for almost anyone. If that's not enough, then move up to the 30 KW model. Kohler makes generators big enough to power your entire neighborhood if you are willing to buy it.

Wiring is not difficult, but depending on your experience level and your desire to obey the local electrical code, you should consider hiring a licensed electrician.

The dirty way

[ShooterNeo]

There's a dirty, and illegal way to do it.

First, if you follow these instructions, remember this KEY STEP
                  TURN OFF THE MAIN SWITCH. Also, NEVER turn that main switch on if the generator is running.
                  Finally, the main switch MUST be double throw.

Forget to follow these instructions, and you can very easily kill a lineman or blow up your generator.

Anyways, you just need a three pronged dryer plug, 2 of them, and sufficient length of heavy gauge wire. You create an illegal male - male 3 pronged plug, and connect your generator socket into the 3 pronged plug in your house used for the clothes dryer.

The reason it is illegal is because this form of installation does not prevent you from connecting your generator to the wiring outside your house. If you left the main switch on, you can energize the dead lines outside with 12,000 volts and kill a lineman.

The advantage? As long as the main switch is double throw, and you don't turn it on when the generator is connected, it is pretty safe. And cheap : a double throw switch and circuit box is $200-$500, while this method can be done for $10.

Re:The dirty way

[vlm]

Forget to follow these instructions, and you can very easily kill a lineman or blow up your generator.

1) Far more likely you'll vaporize your generator. Hook up a 3 KW generator to an entire neighborhood drawing maybe 300 kW and your generator goes poof. The only way you'll kill a lineman if the broken line feeds only your house and the break is an open circuit as opposed to short. Worst case is in between, turning a torn line tangled in a tree into a multi-KW space heater... Kind of like one of those electric charcoal starters but on a much larger scale.

2) The "real" reason it's illegal is, as you'll quickly discover, a male to male cable will probably fall out of the dryer plug at some point and then you've got a couple KW at 220 volts on large bare copper connectors less than an inch apart in a pitch dark room on the floor, or perhaps it'll hit something somewhat conductive on its way to the ground and start a huge fire, or perhaps the kids will play with it and get vaporized. The most likely failure mode of this experiment is electrocution of yourself and/or your family rather than a lineman. After all, the linemen are already working with live power on the "other" side of the broken line... they know what to do, and you don't.

3) You'll also quickly discover that you can't start up your furnace, water heater, sump pump, TV, and microwave all at the same instant although they may all run steady state. Expect alot of fun when the fridge and sump pump simultaneously start up, especially at 2am. You'll get lots of practice reseting breakers and restarting the generator.

4) Built in "permanent" generators are generally built to run and refuel 24x7. "Portables" generally are built to run a tankful and get put away till tomorrow. Portables will have some inherent design engineering "issues" such as gas caps next to red hot mufflers. So be really careful whem refilling. Hurry up and you'll turn into a torch. Also your 4 cycle will inevitably run out of oil at some point, hope you're checking the oil and/or the low oil shutoff works before the engine is trashed.

5) Since this is probably one of the most dangerous things you can possibly do, try not to do anything without thinking about each step very pessimistically. Also no booze, no waking up at 2am to refuel while half asleep. The greatest danger is doing something stupid, and being lucky, so you do it again until you croak.

Other than that, no problem.

My recommendations

[rongage]

The first thing you want is a natural gas powered generator, not gasoline. Nothing like having to take a trip to the local gas station (presuming THEY have power) to fill up the generator every 8 hours or so. This, by definition, will make the generator a stationary unit (not on wheels, designed to be bolted down to a concrete pad).

Next, you want a generator with auto-start, auto-transfer with manual return. You want the thing to automatically kick in if the power dies, but YOU should be in control of when it decides to return to the grid. Nothing like finding out that the power died 10 minutes after you and the family left the house for a couple of days and coming back to a cold house with no power and potentially burst pipes.

Wattage - you will want at least a 5000 watt unit for whole-house use. Forget this idea of running power cords everywhere - unless you like the idea of tripping over power cords everywhere. With the transfer switch mentioned above, the generator takes the place of the grid so your internal house wiring will continue to serve it's duty.

There are several manufacturers of house generator systems. You can find low-end units at places like Home Depot or Lowes. Better units are best obtained from an electrical wholesale house.

Do yourself a huge favor here and hire a licensed electrician to do the work. It'll get done right the first time, the electrical inspector won't get excited (in a negative way) when he sees the work, and the odds of "something going wrong" go way down.

From another guy in Michigan (Westland)...

Passive house heating

[Cyclopedian]

If you get the chance to move out, consider getting a Passive House, where it has super-thick insulation and is hermetically sealed. You wouldn't have to worry about frozen pipes in that kind of setup.

http://www.nytimes.com/2008/12/27/world/europe/27house.html

A couple of comments about having them...

[mykepredko]

Just a comment - we've had a Kohler 15kW Natural Gas powered generator that automatically comes on if power is interrupted for more than 10 seconds for the past year. We've needed it a couple of times now for multi-hour interruptions and it's worked well with the following comments:
1. Get an electrician that knows what he's doing and has experience with automated generators. I spelled out how everything was supposed to be wired and the bozo our contractor hired didn't trust my work beforehand and refused to wire up things like our refrigerator because he thought it drew too much current and then didn't believe my calculations
2. When you look at different generators, you will see that going to a water cooled unit (which is generally what you get when you are in the 22kW range) doubles the price. The 15kW units don't power the whole house, but more than enough to be liveable - you should get your Furnace, Air Conditioning (power goes out in the summer too), kitchen, basic computers & internet service, a couple of bedrooms and a TV/etc. working comfortably
3. The generators need maintenance. Plan on $500 or more a year - you can't do this yourself unless you are licensed for working around natural gas.
4. The units will test themselves once a week. Make sure they come on when nobody's going to be bothered
5. Don't try to do it yourself, the installation is somewhat expensive ($1,500-$2,000) and then you have to do the interior wiring (hooking up the Automated Transfer Switch (ATS) and deciding which circuits should be used).
6. The pricing of the units change during the year and what's going on. Right now would probably be the worst possible time to buy one - I wouldn't be surprised that their prices haven't doubled in your area. You should be looking in the late spring before hurricane season is the best.

myke

some ideas

[scharkalvin]

Generac (http://www.generac.com/Default.aspx) sells complete packages ready to install as well as discrete units and transfer switches. I have one of their 15KW air cooled LNG/Propane generators (only in my case it is for power outages caused by Hurricanes). Very easy to install, mount their transfer panel next to your main breaker panel and transfer some of the loads from the main panel to the generator panel. The unit WON'T run your entire house, but you can put the most important circuits under backup.

If you have piped in LNG this is the way to go. Otherwise you need to bury a 250 to 1000 gal propane tank in the backyard.

    The choice of fuel for generator use would be LNG, Propane, Diesel, and Gasoline (in that order).

Gasoline has the shortest 'shelf life' and is the most difficult to store (ask your fire department!).

    Diesel fuel can last for years with the right additives and can power your car (if you have a diesel car). Diesel engines will also run on JetA (live near an airport?), home heating oil (filter it first!), bio-diesel (rob your nearby McDonalds of their used french fri oil!), even Kerosene. If you buy diesel fuel for generator use make sure you fill out the required paperwork so you don't have to pay the road taxes on the fuel. You can store diesel in the same kind of tanks that home heating oil is stored in.

Re:You all are ... - ELECTROCUTION SAFETY WARNING

[Anonymous Coward]

CAUTION: YOU MAY KILL SOMEONE IF YOU DO NOT TURN YOUR HOUSE'S MAIN BREAKERS TO OFF!
* If you leave the Main Breakers ON you will backfeed power to the entire neighborhood, and the power workers think the lines are dead. Very bad.
* Technically, you need an electrician to wire a breaker/cut-off switch to the generator. In this manner when you switch the generator connection to ON you also switch the Main Breakers to OFF. Expensive, but safe and complies with NEC.
* Most people just use a male to male plug, plug one end into the generator, and the other into some house outlet. If you turn the Main Breakers OFF ~BEFORE~ you do this, it is possible to get power to everything in your house, limited by the breaker capacity and the power generation capacity, and not feed the neighborhood. The relative safety of this is up to others to argue.
* IF THIS MAKES NO SENSE TO YOU, SEEK PROFESSIONAL HELP. Or at least a neighbor with a subscription to Popular Electronics. Your local linemen will thank you!