Sujet : Re: electrical deaths
De : joegwinn (at) *nospam* comcast.net (Joe Gwinn)
Groupes : sci.electronics.designDate : 03. Dec 2024, 18:43:03
Autres entêtes
Message-ID : <mafukjpf3g7onrv7g8m5tc5rk1h46tfurr@4ax.com>
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On Tue, 3 Dec 2024 02:42:37 +0100, "Carlos E.R."
<
robin_listas@es.invalid> wrote:
On 2024-12-03 00:09, Joe Gwinn wrote:
On Mon, 2 Dec 2024 22:44:53 +0100, "Carlos E.R."
<robin_listas@es.invalid> wrote:
On 2024-12-02 22:17, Joe Gwinn wrote:
On Mon, 2 Dec 2024 11:35:41 -0800, Joerg <news@analogconsultants.com>
wrote:
>
On 12/1/24 9:59 AM, Joe Gwinn wrote:
On Sat, 30 Nov 2024 14:24:11 -0800, Joerg <news@analogconsultants.com>
wrote:
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...
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I have many such stories, but this will do for now.
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And I bet that Europe also has its heart-stopping stories.
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Not a dangerous one.
>
The lights in the garden in my father's beach place were connected, the
neutral to one current limiter, the live to another one. The result was
weird: the residual-current device (RCD or RCCB or GFCI) of the house
(here the entire house must be protected by one) triggered at half past
six in the morning, every morning.
>
The electrician was baffled. He found out that the station switched the
transformer one notch at that hour, but why would that cause the GFCI to
trigger nobody could imagine. Finally he found the crossover, and the
thing stopped happening.
Crossover?
>
I don't know how to call it. He found that the live was coming from one
circuit breaker, and the neutral from another.
We would say that the wires were crossed or swapped.
Of course, everything
worked, the lamps were connected to the neutral and the live, continuity
tests say "right", but... two breakers. And the GFCI reacted, somehow.
A GFCI breaker senses the difference in currents carried by hot and
neutral wires. If no leakage, the difference is zero, so the
difference is the leakage. If this leakage exceeds a few milliamps
for maybe a second or two, pop.
The two GFCI breakers each see a very large unbalance, the full
current in that straddling circuit.
On that same place, a cable entered a certain tube with one colour and
exited a different colour.
So there was an inline splice, which is forbidden here. All splices
must be accessible for repair.
>
It is forbidden here too!
>
Not only that, but the same cable was one colour on one end, and a
different colour on the other end, so impossible to trace the cables
from junction to junction box. The electrician that found this out was
astonished. I guess he wasted days figuring out what was going on.
>
If the guy had used cables of the same colour, nobody would have noticed.
Thank god that he didn't.
There was a You-Tube couple in Kiev, Ukraine that made a good income
showing their home-improvement and boat-building stories and methods,
up until when the Russians invaded in 2022. Anyway, the guy did his
own electrical work, and happily made connections buried in walls, his
trick being that he arc welded the copper wires being connected - this
connection was not going to fail at any current level that didn't melt
the wires as well, so what difference could it make? I see his point,
but the US electrical safety authorities probably would not.
>
The house I am living at, has some cables directly embedded in the
mortar. This is forbidden, but wasn't at the time. The correct procedure
now is to place plastic tubing inside the walls and the mortar, and then
drive the cables inside the tubing. The cables can be replaced when needed.
We would say pull the cables.
Embedding a tube versus the wires is the best future-proofing one can
get. As is making the tube too big at first.
Turned out that the installation had been done by three different
electricians, each not knowing what the previous one intended or did.
Yeah. That kind of problem is at the root cause of many bad
accidents.
PS: I do prefer the Euro-style closed terminals that work for
stranded and solid wire. They are allowed in the US, but not all that
common outside of industrial sites. One big advantage is that they
take far less volume than wire-nuts and the like.
>
.<https://en.wikipedia.org/wiki/Knob-and-tube_wiring>
>
Oh! I had seen the article time ago, I had forgotten.
I don't miss those days.
I have many Baltimore and Washington, DC, stories, where there are
lots of transient tenants and skinflint to rapacious landlords.
And a few good landlords. One of my many apartments had a new
landlord with a building that was overrun with cockroaches. We
complained to no avail. One day I caught an immense cockroach (50mm
long) and brought it to the landlord (a lawyer), who was working on
something nearby. His eyes widened - he had never seen one *that* big
- and stammered that I had certainly brought the evidence. He said
that he had an exterminator on contract. I pointed out that there is
no way that critter could have gotten so big if the exterminator was
doing his job, even sporadically. He allowed that this was true. Next
week, the apartment building smelled like a refinery, and there were
paper signs the exterminator had been busy. The landlord was being
cheated by the exterminator.
>
Ah...
I have a non-electrical war story, also from 1970s Washington,
different apartment: One Sunday evening I made myself dinner, and
while cleaning up, the kitchen sink faucet, classic single-handle
design of some kind, and the hot would not shut off, instead roaring
at full volume. Far too loud to ignore and call the landlord in the
morning, so I took it apart. Whereupon I found a 6" (150mm) long
straight piece of steel coat hangar wire. Removed it and put the
valve back together, which now worked correctly. But I could not
imagine how such a long wire could get there, as it could not turn the
corners in the pipes leading to the valve. So I took the other valve
apart. And found another 6" length of steel wire. Removed it. This
was carefully crafted sabotage, intended to generate repeat emergency
repairs. My then landlord was himself a thief, so I never told him -
they deserved one another.
Joe Gwinn