Pole Transformer in reverse

Here is a question for someone from an electric company.
There was a question on here about using a generator if the power goes out. This got me thinking about something. Lets say that your generator is incorrectly installed and is accidentally sending power OUT of your house. Any building that is hooked to the same transformer will get power from your generator. However that would only be a few neighbors.
My question is what happens on the opposite side of the transformer? The standard home transformer is dropping a very high voltage, something like 5000 volts, down to (center tapped) 240/120 volts. So, if you are backfeeding a generator into the secondary windings (240 side), will the transformer increase the voltage to 5000, or whatever it is, in the primary? Knowing how a transformer works, I would assume it would. But do they have some sort of circuit built into these transformers to prevent this from happening?
Also, what would happen if you were backfeeding and the electric company turned their service back on? I would assume that the home generator would be destroyed...... but I could be wrong....
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Any body running a generator should read their instructions, know what they are doing before turning it on , Or hooking it up. Not following recomended startup procedure can mess up apliances and your generator. This means turning off your Main Breaker First. Even with a transfer switch this is common sense. and is safer.. Also if you are not using a voltage controled unit check output voltage before using it . Ive seen them not calibrated putting out 150 - 300 burning out apliances . just because its new doesnt mean anything.. And dont backfeed your house, it wasnt designed that way , wiring problems not previously known can ruin your generator or worse
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That means you don't know when power comes back on. We got ours back at 12:15am this morning.
Is there any way, without significant expense, to safely wire a buzzer to the line side of the main breaker? You could put a switch on it, so it was only potentially energized during an outage.
Regarding your comments about damage from generators; the company that just put my new furnace in says that during a major ice storm a few months ago they had the electronics burn out on 3 new furnaces by generators; and it is not covered by warranty. I figured it was an inadequate sine wave, but I suppose it could also be improper voltage or frequency.
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Hi Wade . Your Idea of a buzzer or light would be a good idea. I was just trying to point out cheap generators can make a mess of your house, When I called Generac about my new 5500 watt " Home Power Plus Unit" because it put out 135 they said ' WE dont recomend that unit for sensitive electonics" and Lowes sold it With a free power transfer system.. Well It doesnt say it on the box or in the manual... Well what the hell... Most everything has sensitive electronics inside these days.. So i returned it and got their better model . I never thought about sign wave, What is it , how do you measure it , what effect does it have on electronics? A friend of mine blew out a 4 day old tv , he returned it no problem, but said his new generac 3000w was putting out apx 150. And it blew in 10 minutes. I know someone else who likes the way his generator makes his lites burn Brighter. And he goes through expensive tvs apx every 4 years.. They dont tell you this stuff on the box or in instructions. Its BS , Alot of people will be buying generators now , and causing even more problems. Youd think the News people would spend 5 minutes educating people on this , A 500$ generator could cause alot of damage quickly..If you are not careful on load issues.. I think the generator cos should be liable for missinformation..
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http://www.mayberrys.com/honda/generator/html/invertgenerator.htm
About 2/3rds of the way down it shows sine waves from various generators.
I have heard that the really cheap ones are even worse.
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The obvious is you shouldn't do it. However, if you did, my guess is that all of the neighbors still have significant load on their lines and the transformer should work perfectly well in reverse, therefore putting a huge load on your generator. It probably will merely stall out ... unless it's a HUGE generator.
snipped-for-privacy@unlisted.com wrote:

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snipped-for-privacy@unlisted.com wrote:

You're correct in your assumption, you'd be developing high voltage on the line side of the transformer. You'd probably be violating code if you did that and potentially (pun intended) liable for whatever injury or deaths your careless actions caused.
On your last point, the genny would probably be spared if it has circuit breakers on its output. They'd probably open when the power came back on.
AFAIK any municipal electrical code will require the installation of a "transfer switch" along with an emergency generator, which disconnects the site's wiring from the mains and connects it to the generator's output.
The safe way of making a temporary hookup to a portable generator to keep a fridge or a few lamps runnning off it is to use extension cords from those appliances which are then plugged into the female output receptacles on the genny.
Just my .02.
BTW, anybody know what procedures the repair crews use to keep from getting fried if someone decides to hook their genny up while they're in the middle of repairing the lines. Do they put big shorting jumpers on "cold" lines to make sure they stay "dead" until they're through and then remove them carefully before they throw the power back on?
Jeff
-- Jeff Wisnia (W1BSV + Brass Rat '57 EE)
"If you can keep smiling when things go wrong, you've thought of someone to place the blame on."
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Linemen have been killed from backfeeding. There is nothing in the transformer to prevent it from occurring. The owner of the generator could be held responsible for any death, injury or damage caused and it is their responsibility to install the proper transfer gear. John

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quoting:

Transformers do work in reverse, but not very effiently. But the you'll be trying power your whole city, quickly overloading the generator.

If the generator was exactly in phase, then no. But chances are, the generator will be out of phase, and blow up.
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