Posted by Derek Broughton on September 16, 2005, 3:53 pm
Vaughn Simon wrote:
> For a lineman to be hurt from a backfeeding generator, four things must
> happen simultaniously:
>
> 1) Some idiot runs a generator connected to his house wiring with no
> proper
> transfer switch and with his main breaker still closed. and...
> 2) Our idiot happens to have an isolated pole transformer that is so
> lightly
> loaded that his generator does not somehow trip. and...
> 3) There happens to be a line crew working outside our idiot's house.
> and...
> 4) That line crew is ignoring proper procedure and working in a criminally
> negligent manner.
>
> I think that #1 and #3 are possible, and #2 and #4 are vanishingly
> unlikely. The possibility of all four of the above happening
> simultaniously is barely worth our time to discuss...yet we do.
We keep discussing it because of Murphy's law. Besides which, I don't
believe #2 is vanishingly small. After our local hurricane experience I
drove down a rural road where practically _every_ pole transformer was
isolated. The whole reason it needs discussing is that the rules exist to
try to ensure that #4 never comes into play.
--
derek
Posted by Dale Farmer on September 17, 2005, 4:09 pm
Vaughn Simon wrote:
> >
> > .... What the concern is if your
> > breaker si closed, and a lineman is working on the lines, your generator
> > is feeding power to the transformer on your pole, and stepping up the
> > voltage (lowering the amps, as watts is watts). Not likely to do any
> > damage with the small generators most folks use, but it is a risk.
> For a lineman to be hurt from a backfeeding generator, four things must
> happen simultaniously:
> 1) Some idiot runs a generator connected to his house wiring with no proper
> transfer switch and with his main breaker still closed. and...
> 2) Our idiot happens to have an isolated pole transformer that is so lightly
> loaded that his generator does not somehow trip. and...
> 3) There happens to be a line crew working outside our idiot's house.
> and...
> 4) That line crew is ignoring proper procedure and working in a criminally
> negligent manner.
> I think that #1 and #3 are possible, and #2 and #4 are vanishingly
> unlikely. The possibility of all four of the above happening simultaniously
> is barely worth our time to discuss...yet we do.
ANd it happens often enough that linemen are injured and killed doing
it. ( News articles were cited previously in the thread of such incidents)
Very small possibility indeed. But when you multiply that small possibility
by the hundreds of thousands of downed power lines in the hurricane
affected areas, it's probability gets quite high.
--Dale
Posted by Solar Flare on September 17, 2005, 6:58 pm
Bullshit. Show me one article to prove this.
The death rate of linemen in Canada is less than 3 per year due to
electrical contact accidents.
Vaughn Simon wrote:
> >
> > .... What the concern is if your
> > breaker si closed, and a lineman is working on the lines, your generator
> > is feeding power to the transformer on your pole, and stepping up the
> > voltage (lowering the amps, as watts is watts). Not likely to do any
> > damage with the small generators most folks use, but it is a risk.
> For a lineman to be hurt from a backfeeding generator, four things must
> happen simultaniously:
> 1) Some idiot runs a generator connected to his house wiring with no
proper
> transfer switch and with his main breaker still closed. and...
> 2) Our idiot happens to have an isolated pole transformer that is so
lightly
> loaded that his generator does not somehow trip. and...
> 3) There happens to be a line crew working outside our idiot's house.
> and...
> 4) That line crew is ignoring proper procedure and working in a criminally
> negligent manner.
> I think that #1 and #3 are possible, and #2 and #4 are vanishingly
> unlikely. The possibility of all four of the above happening
simultaniously
> is barely worth our time to discuss...yet we do.
ANd it happens often enough that linemen are injured and killed doing
it. ( News articles were cited previously in the thread of such incidents)
Very small possibility indeed. But when you multiply that small possibility
by the hundreds of thousands of downed power lines in the hurricane
affected areas, it's probability gets quite high.
--Dale
Posted by Solar Flare on August 23, 2005, 12:00 am
"deserve it" was never posted or implied.
I guess the thread has now degenerated into a trolling match again. The
insults and maturity level shows one more time here.
> Dale Farmer wrote:
> > Solar Flare wrote:
> In any case despite Flare's stupid insistence that anyone who does suffer
> from such backfeed deserves what they get, it's clearly _possible_ and
> that's why we have safety regulations.
> --
> derek
Posted by CM on September 23, 2005, 8:55 pm
>>> The correct way to do this is to get one of those generator switch over
>>> panels,
>>>that have an L14-30 male connector on them. Then just get the cable,
>>>and
>>>a pair of the connectors to make up an extension cord for your
>>>generator. You
>>>can also get an external box permanently wired up to the outside with
>>>the
>>>L14 connector, so you don't have to run the cable in through a window or
>>>door left open. May have to get a locally licensed electrician to do the
>>>work,
>>>modulo your local electrical code. Positive disconnecting means that
>>>has
>>>no possibility of connecting your generator to the utility power feed
>>>are
>>>often required by law, due to the non-trivial number of utility workers
>>>who
>>>got electrocuted ..............
> I am sure this is one of those city 'legends' we have all heard about.
> I suspect the real reason is that the utilities don't want uncontrolled
> generators on the grid even when it is operational. As far as
> electrocuting utility workers, there would be such a hugh load (the
> entire grid) on your generator when it was supplying power to an
> otherwise unpowered grid, it will see that load as a dead short circuit
> and trip its own circuit breakers. It sure as he... won't be able to
> electrocute anybody, but you will burn your generator up if it's circuit
> breakers don't function very quickly.
If the point of failure cuts the backfeeding fool's house off from the rest
of "the grid", it won't overload the generator, but any attempt to
reconnect the fool's house to the grid becomes unduly hazardous, both to
lineman and to the fool's generator.
The possibility of overloading the generator via backfeeding is not a valid
excuse to do it, it is another reason for not wiring things incorrectly.
Codes exist for a reason. Pay attention to experts who know better.
CM
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> happen simultaniously:
>
> 1) Some idiot runs a generator connected to his house wiring with no
> proper
> transfer switch and with his main breaker still closed. and...
> 2) Our idiot happens to have an isolated pole transformer that is so
> lightly
> loaded that his generator does not somehow trip. and...
> 3) There happens to be a line crew working outside our idiot's house.
> and...
> 4) That line crew is ignoring proper procedure and working in a criminally
> negligent manner.
>
> I think that #1 and #3 are possible, and #2 and #4 are vanishingly
> unlikely. The possibility of all four of the above happening
> simultaniously is barely worth our time to discuss...yet we do.