Oh, gee. Don't get started askign for specifics. Usenet is for wild ass
statements completely lackig in truth.
Since you asked, Myrtle Bingle was using her suicide cord in a power cut in
Arkansas in 1956. She neglected to turn off the mains, and killed David
Petersen, who was working on the line outside her house.
Myrtle was a darky, and she was promptly arrested and tried. Spent the rest
of her life in prison. Died last year.
Remember, now, this is Usenet. You can't believe everything you read.
Here are two Fatality Assessment and Control Evaluation (FACE) reports
on the deaths of outside wiremen do to generator back feeds.
Well we aren\'t no thin blue heroes and yet we aren\'t no blackguards to.
I'm surprised nobody's mentioned being sure to have (2) hot leads and
neutral, so you can power 117v circuits.
I've done this sort of thing many times over the years, but via single
117v 15a or 20a branch circuit. Main opened first, ditto all breakers
(which are accurately labelled as to which load). Of course circuit is
chosen so as to power selected "phase" which luckily has covered the
necessary loads. Then one breaker at a time on, and maybe rotated as
necessary. (Refrigerator does not need power 100% of time, nor does
furnace blower. Yada, yada.)
At a friend's house, opening main breaker one time, caused it to fail
to close forever more. Which sped up replacement.
I was working on a trailer with a friend of mine. He want and "turned off
the mains" and then we found a couple sockets hot.
Turns out, he'd turned off the breaker for the dryer, thinking it was the
mains. I turned off the rest of the breakers.
How easy it is to make mistakes like that....
Of course. 4 wire 240V is 4 wire 240V, and breakers don't care
which terminals are the innie and which are the outie ;-)
We were installing a new main panel, and just when we wanted
to transfer the feed, the local power company went on strike.
Out of necessity (because so much had been transferred to the
new panel), we ended up temporarily backfeeding the new main
panel thru its dryer circuit from the old main's dryer circuit.
[The new main didn't have a meter installed nor the main
feed of course.]
During the great ice storm, a friend and I helped a muncipality
out by doing inspections of generator installations. One of them
(installed by a professional electrician) wired the generator
directly into the panel's backplane (they were lucky, they
just got their power back, and all we did was remove the
backfeed and reestablish the real feed). The main breaker
was wired open.
During the same ice storm, we spliced a 100Kw generator directly
into a main panel (after physically disconnecting the line
feed). [This was at the municipal works garage, and became
a base for emergency crews, road clearance, and included the
army's food/fuel distribution center.]
In an emergency, you gotta do what you gotta do. However,
if you do have to do this, you have to do whatever you can
to make it safe (ie: wire or padlock or physically disconnect the
main). Secondly, if you are preparing for an emergency
_before_ the emergency takes place, do it right. Installing
outlets and obtaining a suicide cord is not right.
[Theoretically, an illegal backfeed can earn you a $6000 fine
here. Worse if you hurt someone.]
Chris Lewis, Una confibula non set est
It\'s not just anyone who gets a Starship Cruiser class named after them.
All I can say is that here in SE Florida since Hurricane Wilma this week,
with 6 million people out of power, with my neighborhood as a sample, there
must be about 1 million backfed generators hooked up and running. It is
not just commonplace; it is the norm.
One neighbor had a (gypsy) electrician install a 4-wire twist-lock socket
in his garage specifically for backfeeding through a suicide cord.
Just stand in the electrical aisle of Home Depot for 5 minutes. You will
see a steady stream of people buying wire and plugs and asking how to make
a backfeed connection.
The same thing happened on a slightly smaller but still massive scale last
year after Hurricanes Jeanne and Frances. I don't recall any reports of
utility workers or users being harmed by the practice. There were
certainly more people poisoned by carbon monoxide from generators than hurt
or killed by electrocution from backfeeding or other misuse.
Do you know what a step-down transformer does? It converts 7200 volts to
240 & 120 volts. Do you know what happens when you backfeed 240 volts
through it? It puts 7200 volts back into the line. Do you know how little
current it takes to kill you at such a voltage? Very little. Your limited
knowledge and limited reasoning power are forming dangerous conclusions.
Stop doing that. Someone may get killed because of what you are saying.
I'm not an electrician but here's my 2 cents.
You can't ever let your generator feed back down the power lines. The main
breaker must be off and must stay off. It doesn't matter if your generator
can't possibly power the whole neighborhood or the whole grid..If people
hook up generators to their house wireing, even for a few seconds, without
isolating the house from the line,.sooner or later, somewhere, the right set
of conditions will exist to electrocute a lineman. You can't take that
chance. The main breaker must be off. There must be no chance that anyone
will turn the main breaker back on before the generator connection is
removed. I can see a lot of ways for this to go wrong.
I don't see where there's risk of back feeding through the neutral line any
more than there would be if you have a proper generator transfer switch.
Does a transfer switch isolate the neutral?
Then you haven't lived long enough, or inspected enough
installations..... Having a Transfer Switch that doesn't switch the
Neutral is applicable in the NEC, and legal in some situations.
However, and this is a BIG However, if the System Ground should
become faulty or the Netural resistance to ground start to rise
due to corrosion or other problems, then out of Ballance Backfeeding
on a 120/240Vac Single Phase system can happen. Nothing mechanical
stays the same forever, and forever is a very long time. Shit Happens,
and folks that don't understand that are doomed to live the results,
for when the wrong "Shit Happens" in their world.......
Some folks choose to only switch the Hot Legs, but the better way to
do it is to switch both Hot and Neutral, and only keep the Ground
The last time I looked at "real" transfer switches from the major brands
through about 600A, virtually all were solid neutral units. You could of
course use a three pole (a.k.a. three phase) unit to switch the neutral
in a 120/240V application, but you'd likely have to special order it to
get the single phase monitor and control electronics. All of the little
"Gen-Trans" and similar consumer level units I've seen are solid neutral
I'm pretty sure that it's unlikely you'll see a transfer switch that
switches the neutral as well outside of a fairly large industrial /
Your point sounds valid, and I certainly believe "ship happens" (given
enough time shit will always happen), but can you cite a specific make and
model transfer switch for a residential application that switches the
The picture is a bit small, but it sure looks like a pair of 2 pole
contactors. I can't tell if they have auxiliary contacts installed for
electrical interlock. It looks rather like the auto transfer switches
I've seen on RVs. If they are indeed 2 pole contactors then you're
either running 120V only or have a solid neutral.
I built a small transfer switch myself with a pair of contactors with
auxiliary contacts installed to allow for electrical interlock of the
contactors coils. When a contactor is energized the NC aux contacts open
the circuit to the coil of the other contactor preventing it from being
energized. Three possible states, one contactor on, the other contactor
on or both contactors off.
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