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From: "Carlos E.R." <robin_listas@es.invalid>
Newsgroups: sci.electronics.design
Subject: Re: electrical deaths
Date: Mon, 2 Dec 2024 22:44:53 +0100
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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:

....

>> Polarization can save the day with toasters and similar appliances. Then
>> you can make sure that neutral comes in at the top end of the meanders.
>> In the US, 99+ percent of cases will not have line and neutral reversed.
> 
> I think that the 99+ percent is quite optimistic, especially on older
> buildings.  Back when I was an apartment-dweller, ran into all manner
> of trouble, to the point that one of the first things I did in a new
> apartment, was to turn the power off and opened all electric boxes,
> and straighten out the "carpenter wiring", much of this being
> dangerous.
> 
> War Story One:  In the 1970s in Washington, DC, my boss was having
> considerable problems with the lights in his newish house in the
> suburbs.  For instance, when he turned one light on, an unrelated
> light would go off.  I said it sounded like some kind of grounding
> problem.  Eventually he invited me to dinner in his house, and bring
> your voltmeter.  Which I did.  It turned out that the solid copper
> wires at every electrical device (wall switch, outlet, light, et al)
> were loose - the electrician (or his assistant had forgotten to
> tighten all the terminal screws down.  (Stranded wire was not used
> then.)  So boss called the builder to have all those neglected
> terminal screws tightened properly.  He was lucky that there wasn't a
> fire.
> 
> War Story Two.  Ten years later, in Baltimore, MD, some friends
> complained that their kitchen light (in the center of the ceiling)
> flickered, and mentioned that when they used the sink in the washroom
> off the kitchen, sparks fell from underneath that sink.  I didn't
> believe them at first, but they persisted.  It turned out that the
> building (which was quite old) still had some old knob-and-tube
> wiring.  The plumbers had recently replaced the drain pipe from the
> bathroom above the washroom with a new copper pipe, and had barged
> through the existing knob-and-tube wiring, breaking the return path,
> but accidentally making the drain pipe live.  The current made it from
> the copper drain pipe to the existing cast iron drain through the
> hardware on the washroom sink.  Stopgap was to firmly ground the drain
> pipe.  I assume the owner of the building had words with the plumber,
> and got an electrician.  Anyway, nobody was hurt, and nothing burnt
> down.
> 
> I have many such stories, but this will do for now.
> 
> And I bet that Europe also has its heart-stopping stories.

Not a dangerous one.

The lights in the garden in my father 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.

On that same place, a cable entered a certain tube with one colour and 
exited a different colour.

Turned out that the installation had been done by three different 
electricians, each not knowing what the previous one intended or did.

> 
> Joe Gwinn
> 
> 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.

-- 
Cheers, Carlos.