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Old 08-15-2013, 09:58 PM   #1
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Generator backfeeding incidents


Let me preface this by saying that I firmly believe all generator installations should be installed with the proper switch or interlock kit to prevent accidental backfeeding. However, I was wondering if anyone has any documented cases of someone leaving the main breaker on when using a generator, and the generator being destroyed by line power or simply overloading/tripping due to load.

I've read online about lineman deaths as a result of "improper generator installations," but I'm always surprised that these stories seem very vague and don't seem to get a lot of attention, at least in my area. I'm sure this must happen more often than it seems.

Any input welcome.

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Old 08-16-2013, 05:23 AM   #2
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Generator backfeeding incidents


Here is one link:

http://www.electricenergyonline.com/..._news&id=38786

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Old 08-16-2013, 06:08 AM   #3
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Generator backfeeding incidents


Despite the high importance of safety now days,
there's always gunna be a small amount of people who take dangerous chances
with no regards to the safety of others.
The best thing to do is what all electricains should do every time
Always assume a line is live till proven otherwise,
And always earth it out as a second backup.
Cause there's still plenty of fools out there.
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Old 08-16-2013, 06:31 AM   #4
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Generator backfeeding incidents


have freinds who are linemen ... and i hear the stories when they get called to other states to help usually one gets killed every storm ...


since the transformer on the pole is dropping the voltage down to 120 ...

when you hook it up in reverse ... ie power a gen improperly the transformer on the pole works in reverse and then sends HIGH VOLTAGES back through the power lines ...


If i am running a gen "portable" ... they will make us shut it off no matter how its hooked up ....while they are actully doing the work
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Old 08-16-2013, 07:08 AM   #5
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Generator backfeeding incidents


And even if a lineman is careful and checks that the line is not energized someone could subsequently start a generator while the lineman is working.
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Old 08-16-2013, 07:34 AM   #6
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Generator backfeeding incidents


http://www.electricenergyonline.com/..._news&id=38786

http://www.oshrc.gov/decisions/html_2007/06-0166.htm
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Old 08-16-2013, 09:19 AM   #7
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Generator backfeeding incidents


Quote:
Originally Posted by Philly Master View Post

since the transformer on the pole is dropping the voltage down to 120 ...

when you hook it up in reverse ... ie power a gen improperly the transformer on the pole works in reverse and then sends HIGH VOLTAGES back through the power lines ...
I have always wondered about this... If say a homeowner fired up a gen and backfed the system...Wouldn't the load on the system imideatly trip the generator breaker. For example, there is a transformer on the pole outside my house. As best I can tell there are at least 6 houses on that transformer. Not fully understanding the power grid ( I have a pretty good grasp) It could be more, maybe. Anyway, the load those houses had ( refrigerators, freezers lights, tv, computers, etc) when the power goes out would be a lot more than the 50 or so amps a gen could put out. Now understanding what I do, if you increase voltage you drop available amps, Correct????? So stands to reason if you feed back thru that transformer, back to the primary there would be a huge load that the gen could not handle...I would think.

This, hopefully, will lead to an interesting discussion.
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Old 08-16-2013, 09:51 AM   #8
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Generator backfeeding incidents


Quote:
Originally Posted by danpik

I have always wondered about this... If say a homeowner fired up a gen and backfed the system...Wouldn't the load on the system imideatly trip the generator breaker. For example, there is a transformer on the pole outside my house. As best I can tell there are at least 6 houses on that transformer. Not fully understanding the power grid ( I have a pretty good grasp) It could be more, maybe. Anyway, the load those houses had ( refrigerators, freezers lights, tv, computers, etc) when the power goes out would be a lot more than the 50 or so amps a gen could put out. Now understanding what I do, if you increase voltage you drop available amps, Correct????? So stands to reason if you feed back thru that transformer, back to the primary there would be a huge load that the gen could not handle...I would think.

This, hopefully, will lead to an interesting discussion.
Yeah that's what I have always thought. It seems lit would be almost like a dead short to the generator.
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Old 08-16-2013, 09:56 AM   #9
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Generator backfeeding incidents


lineman around here never seem to check for improper installations, and there have been times when nearly every house down the road has a generator hooked up.

I guess they ground the lines and/or check them first.
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Old 08-16-2013, 10:36 AM   #10
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Generator backfeeding incidents


Quote:
Originally Posted by Kyle_in_rure View Post
lineman around here never seem to check for improper installations, and there have been times when nearly every house down the road has a generator hooked up.

I guess they ground the lines and/or check them first.
Two things have really changed post-2000 or so, from what I can see: generators got really, really cheap, and in response to that power companies have revised policies. I know it is standard practice for my co-op to go into any situation with full equipment for energized lines, isolate those lines, then ground them before doing anything else. I do recall the Pike story from a number of years back and it was clear they took shortcuts and avoided safety precautions that probably would have saved the man's life.

Another benefit I have: my co-op also offers free inspections for any generation equipment (emergency generators, solar, etc.). They will look it over to make sure it's safe, they'll test it by isolating the service, starting generation, and testing at the meter socket.

I'd imagine you won't hear much about the cases where the generator circuit breaker fails and burns up the generator windings, because I don't think those manage to get reported. After all, would you report that you hooked up something illegally? (I suppose there are always those people who call police to report their pot was stolen, but that's fodder for Leno jokes.)
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Old 08-16-2013, 12:50 PM   #11
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Generator backfeeding incidents


Quote:
Originally Posted by danpik View Post
I have always wondered about this... If say a homeowner fired up a gen and backfed the system...Wouldn't the load on the system imideatly trip the generator breaker. For example, there is a transformer on the pole outside my house. As best I can tell there are at least 6 houses on that transformer. Not fully understanding the power grid ( I have a pretty good grasp) It could be more, maybe. Anyway, the load those houses had ( refrigerators, freezers lights, tv, computers, etc) when the power goes out would be a lot more than the 50 or so amps a gen could put out. Now understanding what I do, if you increase voltage you drop available amps, Correct????? So stands to reason if you feed back thru that transformer, back to the primary there would be a huge load that the gen could not handle...I would think.

This, hopefully, will lead to an interesting discussion.
That's what I always thought. They should only be dangerous in very local breaks, but I could be wrong.
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Old 08-16-2013, 01:23 PM   #12
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Generator backfeeding incidents


The average small home generator would trip its breaker if connected to the dead grid. However larger generators can be dangerous for line men. There have also been incidents where the drop to single has been down and the line was live because of improper transfer switching.
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Old 08-16-2013, 02:52 PM   #13
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Generator backfeeding incidents


If only meters had anti-islanding features. You'd think with all of the smart meters being installed these days that this ongoing and serious safety issue would become a thing of the past.
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Old 08-16-2013, 06:36 PM   #14
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Generator backfeeding incidents


Quote:
Originally Posted by raylo32 View Post
And even if a lineman is careful and checks that the line is not energized someone could subsequently start a generator while the lineman is working.
Thats why you should always put a ground jumper on the incoming lines
after you have tested them and BEFORE you work on them.
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Old 08-16-2013, 10:19 PM   #15
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Generator backfeeding incidents


we had a guy around here back feeding a line like this , he wasn't really aware he was doing anything wrong until they found him.they told him to shut it down or they would take it & fine him.all our co-ops are suposed to ground everything first.like there sign on the truck says "IF IT ISN'T GROUNDED , IT ISN'T DEAD!"

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