Good info. I recently purchased a 3500W Generac propane generator that I'll be hooking up to the house under the watchful eye of my father. He's an electrician/HVAC/appliance/handyman all rolled into one. Obviously I won't be able to power everything at once (or for some appliances, at all) but it will be nice to at least have refrigeration!

Well I think I'll chime in on this as I am an electrician, and have experience living in this type situation. As I have mentioned before, we went through a once in a life time ice storm last January, and from all reports it took 85% of the electrical infrastructure to the ground. I was out of power for 3 days, but some were out over a month.

As I read over the article I wanted to comment on a few points.

First off, turn off the main breaker. This is most important to protect you, your home and the life of the utility worker. The transformer at your home most likely takes 4160 volts down to 220 volts, it is a ratio thing. So if the power is out, and you back feed the grid by not turning off your breaker you are taking 220 volts out of your generator, and the transformer is making it 4160 volts. This is running back down the lines that may be down, across vehicles, or in the hands of the lineman.

Second. It is possible for a main breaker to fail. By that I mean it is possible to weld the contacts together, so that even though you turn off the handle the contacts may not open up. The best way to prevent this is with a disconnect, or transfer switch.

Third. This is IMPORTANT! Don't run your generator in the garage...no matter how much you think you have the door open. There was a elementary school teacher and her daughter that were killed during the ice storm by this very thing. Carbon monoxide is no joke and will kill you before you know it. Run the generator outside. It will not matter if it is raining or snowing on it, that's fine.

Ok so for some examples. I have a 1500 square foot ranch home. We have natural gas heat, cook stove, and water heater. I have a fridge, deep freeze, and all the modern luxuries that draw the power. Before winter set in, I installed a plug at the condensing unit of my air conditioning system. What I did was to take the end of a 12 gauge extension cord, cut it and with the breaker off to the a/c I hooked the wires under the lugs on the a/c contactor inside the unit outdoors. I let the extension cord end come out the bottom, and put everything back together. When the ice hit and the power went out, I turned off the main breaker, pulled the generator out, connected to that cord under the a/c, and started the generator. Mind you that the a/c breaker was still off, so I went in and turned off all the other breakers, giving noticed to the only other double pole breaker in my panel that runs the clothes dryer. Then I turned on the breaker for the a/c which is now the incoming power, and started turning on the other breakers in the house. What I found was that my 5500 watt coleman powers everything in my home, blower for the heat, all the lights, tv, sat, computers, oh yeah, fridge, deep freeze, everything... EXCEPT, obviously wont power the clothes dryer, the microwave, and one I had not thought about, the garbage disposal... (found that out real quick when instinctively hitting the switch one day...). The gas supply for my generator would last around 2 hours at full house load (1 gallon tank), so we would run for 2 hours, then let it stay off for 2 hours etc. You find out real quick that keeping a gas supply can be more difficult than you might expect. I have 10 gallons staybilized, but that only lasts about 2 days. Well that's our story. Changes for this coming year... I am looking for a wood burner, and will add at least another 5 gallons of fuel to my supply. We are already having a strange October, it is pretty cool, pretty early. So, best to be ready. Good luck.

This is a good, safe sequence for setting your home up on a generator system.
I was talking with an electrician I worked with about this very situation and he was adamant that a transfer switch be installed with the system to isolate the generator from the "grid" power system in case of power restoration with the generator attached and operating, big nasties would occur through the interaction of the two power sources on one wiring system.
I objected to that with the main breaker in the panel would be open so that there was no continuity between the two system and he informed me that the "gap" between the breaker contacts was not very wide and a sudden inrush of current could easily jump that gap and destroy the generator and possibly cause worse damage to your house. He did tell me what the gap measurement was but I can't remember exactly, it was on the order of a less than a tenth of an inch.
Personally, I'm still not convinced that any problem could occur if the grid power returns while I have my generator attached and operating but I can pull the meter if necessary and avoid any possibility of problems.
Until the power company sees the broken seal on the meter can when they do their "pay us" visits. :oops:

March 8, 2009
Lon Schultz, B.E. E.M.T. B.N.H. and D.N.M.

In an emergency situation we all might need to do things we are not trained for or accustomed to doing, dangerous things that require care, like minor surgery. Electricity is no different.

Remember, if someone else can do it, you can learn to do it also.

You can do this. Just follow these instructions exactly and completely!

These instructions are for a 220 V generator only.

First, construct or have constructed an extension cord, one end with a plug that goes into the 220 V outlet on the generator. The other end needs to have a plug for a 220 V outlet in the house, air conditioner for 6KW or less or an electric dryer for 10KW or less. If possible, it would be best to have an electrician install an RV outlet on the outside of your house and make up the cord. The wattage and subsequent amperage of the generator should match the outlet in the house, but it is not necessary; however the extension cord wire must meet or exceed the rating of the generator.

This cord will have a plug on each end, and is very dangerous! If you plug it in and start the generator, so DON'T!

Here are some guidelines for cord construction:

* With up to a 4 KW 220V generator a grounded 12 Ga. wire rated at 20 amps is adequate.
* With up to a 6 KW 220V generator a grounded 10 Ga. wire rated at 30 amps is sufficient.
* With up to a 10 KW 220V generator use a grounded 8 Ga. wire rated for 50 A.

Of course you can always use a larger wire.

Cord Construction methods: Each 220 V plug will have three or four connections, two hot, some times one neutral and always one ground. On the three pin plugs the neutral and ground are the same. The plugs might be different or the same, it doesn't matter. The pin is round and the lug is flat like a knife.

What matters most is that the ground from each plug is connected to one another and then that any neutrals are connected to one another. If one plug is a three lug and the other is a four, connect the ground and neutral together at the four pin plug. The ground and neutral are essentially the same.

It is preferred that a green wire is used for the ground and that a white is used for the neutral, again, the white and green can be connected. Most ground lugs or pins are located away from the hot lugs, at the bottom or top of the plug body, if there is a neutral it is near the ground.

The hot lugs are always a lug and the ground is usually a pin.

The hot lugs usually oppose each other and the hot wires are usually black and red. Once the ground and neutral are connected, connect the hot wires, one to either side, it does not matter which hot lug they go to.

Always use the cable clamp on the plug and pull on the cable to test it before use. If you have a multi-meter (and you should) use the ohms or continuity section to test continuity between the grounds and neutral if there is one and then the hot connections from one plug to another.

Second. Turn off the main breaker. (I can't overemphasize this) then turn off all other breakers! If you don't, someone can be killed and at the least, your generator will overload and blow breakers.

Third. If possible ground the generator, to the ground with a grounding rod or to a pipe. Then connect the cord between the generator and the house.

Fourth. Start the generator and let it warm up a little. The generator should be out side or at least in a garage, with the door cracked or open NOT IN THE HOUSE!

Fifth. Turn on one breaker to one room with lights only, like the bathroom. If all is well, turn on another breaker to another room with lights only, and then all other breakers for the lights only. This is to avoid wiring and load problems. If there are problems check your wiring! So now the house is mostly lit. Turn off any unnecessary lights.

Try this before you need it; there might be problems!

Sixth. Depending on the power of the generator, turn on other breakers to rooms with freezers and Refrigerators, one at a time with 10 to 20 seconds between. High wattage devices like electric stoves and air conditioners, or water heaters will usually overload your generator and blow breakers, so don't try and use them unless you have a high wattage generator. If this happens just turn of the device and reset the breakers.

Seventh. Shutting the system down is basically in the reverse order.

No matter what, shut down the generator before any wires are disconnected, as it is a shock hazard, otherwise.

You should go through the sequential turning on of the breakers each time you turn on the generator, with the main breaker off.

Dr. Lon Schultz has over 50 years in electricity and electronics, taught Industrial maintenance at A.T.U. and electricity for local electricians.

http://standeyo.com/NEWS/09_Sci_Tech/090408.wiring.generator.html