25 July 2011

ICP switch causes unforeseen problems for home owners

5 comments:

  1. Hi
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  2. The ICP switch fitted to my property is a single pole device. In a previous life I was an expert witness in cases where individuals had been injured by incorrectly wired single pole switches used to isolate the incoming mains supply. The regulations in the UK specify double pole switches for primary isolation of the incoming supply.
    I have heard that the single pole switch "is safe" because the RCD (earth leakage trip) will protect if some unsuspecting customer makes contact with a live wire whilst the power is "off".
    In my short time in Spain I have found RCD's which have seized mechanically due to damp conditions in the consumer unit. I have found "live" blue wires, "live" black wires, black "earth" wires etc etc etc.
    Ultimately with the millions of ICP switches which are likely to be fitted, there is a finite probability that some poor customer will be injured due to a faulty installation.
    These potential dangers could have been avoided by the sensible fitting of a double pole ICP!

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  3. Hola Anonymous

    This may sound odd to a safety expert, but as far as Iberdrola is concerned the ICP´s primary function is not as a safety device but as a power control switch. A double pole MCB should be fitted next in-line (on the consumers side) then the RCD then the double switches for the sub-circuits. This is the responsibility of the electrical installer and not Iberdrola. The installer issues the electrical certificate (boletin) and is responsible for testing the safety of the installation, not Iberdrola. That said, some regions in Spain specify a double pole ICP being fitted.

    I have tested many properties and found reversed polarity, and it is especially not uncommon in older properties. If a serious injury was ever taken to court it would be the person who signed the boletin in the dock facing the judge.

    Si, that´s the theory behind the RCD, (I think you mean "while the power is on") but in practice.... Ask the person who told you that to stand in a shower for a bet then stick 230 volts up their bum and see if the RCD trips out before they fry alive, he he.

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  4. Thanks for that reply Tony.

    One of the cases I helped to prosecute was that of a toddler who lost the use of her right hand in a council flat.
    The toddler's mother found her unconcious in front of a wall mounted electric fire with a badly burned hand clutching the ceramic element of the fire. The fire was switched off at the wall switch but the element was red hot.
    The mother, a nurse, knew the drill and pulled the girl away from the fire.
    The hot element came with her and had to be sugically removed.

    The council lawyer claimed it was negligence on the part of the mother.
    He accused her of switching the fire off after the event.
    In fact the sequence of events eventually proved that the fire had never ever been switched on.(It was the height of summer.)

    The fire was an old design.
    A metal case with two reflectors held two tubular heating elements.
    These were ceramic tubes wound with nichrome wire terminated with conical brass end caps.
    They were supported in the framework by spring loaded metal cups running in ceramic insulators.
    A simple protective wire grill projected out from the front of the fire.

    I had a very good engineering friend (sadly deceased) who's favorite quote was:-
    "Anyone, who claims to have never made a mistake, has never made anything."

    In this case there were two mistakes which were critical because the wall switch was single pole.
    The wiring was in metal conduit which carried earth to the frame of the fire.
    The wires were red and black.
    The first mistake was in the distribution box for the flats on that floor. Live and Neutral colours were reversed.
    The second mistake was by the electrician who installed the fire. He connected the single pole switch in the red wire but didn't check it electrically other than to test that it switched power to the fire on and off

    We ultimately tracked the sequence of events.
    The toddler put her hand and arm through the grill and grabbed the element.
    The wiring mistakes meant the element was live.
    (the single pole switch was actually in series with the neutral side of the mains)

    The shock she received knocked her out and a muscle spasm pulled out one end of the element which connected to the earthed metal frame. The flats didn't have RCD's, so the element heated with current flowing through from live to earth.
    This sequence of events would not have occurred had the switch been double pole.

    I don't know how old that toddler is now, but I'm pretty sure she thinks that a double pole switch would have been far better than the compensation she received. My own experience was that I was obviously black listed by the local council for daring to contradict their version of events, hence my desire to remain anonymous.

    Iberdrola are a huge company and the safety of their customers should be paramount. The ICP is the first device between the Iberdrola supply and the customer. When it trips it leaves the customer without power but not fully isolated from their supply. I would like to know why the Main switch, and the RCD MUST both carry enough contacts to totally isolate the supply but the primary (and sealed!) switch does not. It just doesn't add up technically, though I guess it might to fool the odd government ministry into passing legislation to boost Iberdrola's profits.

    I personally nearly died when three apparently non electrical events combined together to get me strapped across a 440 volt three phase supply, so I have a great respect for the effects of probability at the extremes. Anything which can reduce these events should be mandatory.

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  5. Very interesting and disturbing story.

    Realistically Iberdrola are no more than a government agency to collect money for electricity usage. Their legal responsibilities to the consumer are very different compared to the electrical distributors in the UK and put the onus on the installers.

    Saludos

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