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Defibrillator installation

IronFreely

Hi, Ive been asked to fit a couple of defibrillators at my local town hall. I dont know why but there’s something in the back of my mind telling me that there may be some specific requirements. I might have a memory of being told once that theres a specific city and guilds AED installation  course but google hasn't given me much there… I had a look through my shiny new brown book but didn't find anything of significance, I like the cover of new book, feels tougher than the previous ones but i did rely like that calming shade of blue.

Im your average qualified sparks who mostly rocks the domestic world and I’m obviously signed up to a scheme and have the usual insurances and qualifications. Any way so, beyond the normal every day rules regarding fault protection, earthing and bonding etc is there anything else anyone would advise me to consider before accepting the job?

One thing I’ve considered is that these things go on an exterior wall and appear to be in metal cabinets, having not yet received the instructions I may find the casing is technically an exposed conductive part and may require earthing so that may bring up the question of exporting PME.  However I have been told by the person booking the work they are rated IP65 and he believes they are class 2/double insulated so that would suggest perhaps the external casing would not require earthing and as you cant plug a lawnmower into it perhaps its not going to be a worry connecting the it to a final circuit on a property with PME. 

Id appreciate some thoughts and advice especially from anyone with experience of fitting them as Ive never been asked before, id rather come on hear and ask a rookie question than make a rookie mistake when by now I should know better! 

Thanks in advance 

still running freely 

Parents
  • 0

    I have installed a couple of the AED units in phone boxes. The manufactures instructions say the the unit needs to be TT earth. The locked box for these was plastic with a 24V power supply for the keypad, a fan, a heater pad and the solenoid to open the box. The problem with phone boxes is they are double insulated. I did contact the manufacturers to find out why TT but got no response. 

    The defibrillator itself contain a long life battery with an expiry date and is not rechargeable. I forget the chemistry involved but it was not one of the common types. 

    From the training course I went on to use a defibrillator I was lead to believe it was to start a dead heart. It was made clear that performing CPR was the most urgent need. If the person has had a heart attack requiring a defibrillator they are already dead so you can do no harm by performing CPR. The prognosis was not very good  even with timely CPR and a defibrillator but it was much better than doing nothing.

  • 0 in reply to kfh

    I was told by a medic that a defib stops your heart so it starts on its own good unconfused rhythm. Rather than it starts a stopped heart.

  • 0 in reply to ebee

    seconded- both St Johns folk who do our scout leader training and also the chap at the FA at work course

    both described it as a more of a stop it fluttering and reset to a steady beat, rather than an actual start.

    The defib shock energy  is 150-300  joules so well over the 10 joule absolute max for non lethal electric fences and the 1 joule action limit we have at work for deciding if things need bleed resistors or not.

    Hence it is very important not to be holding the patient during the zap- the modern machines actually say  something to the effect of 'stand clear' prior to it.

    Mike

  • 0 in reply to mapj1
    mapj1 said:
    The defib shock energy  is 150-300  joules so well over the 10 joule absolute max for non lethal electric fences and the 1 joule action limit we have at work for deciding if things need bleed resistors or not.

    'Tis a very strange thing that the cure for a shock which puts you into VF is another one.

Reply
  • 0 in reply to mapj1
    mapj1 said:
    The defib shock energy  is 150-300  joules so well over the 10 joule absolute max for non lethal electric fences and the 1 joule action limit we have at work for deciding if things need bleed resistors or not.

    'Tis a very strange thing that the cure for a shock which puts you into VF is another one.

Children
  • 0 in reply to Chris Pearson

    yes - but it is a long shock, compared to the natural heartbeat period that is likely to cause fibrillation,

    Note the curved nature  in the boundary of zone 3 - temporary arrest, no VF correspond to fractions of a second - ths is no accident, a slow adult heartbeat from a fit human maybe 50bpm, is a touch over 1 second period,  while a fast one of perhaps 150bpm - running very hard, would be 1/3 second.

    The longer the shock duration the greater the fraction of the population would be at risk from it - so there is a general statement that longer shocks or higher current ones are the more dangerous.

    The Defib zap in contrast is a short duration shock,  of high current can be 10-20A peak, but lasting for a few milliseconds at most. Actually most modern machines deliver bursts of shorter 'biphasic' pulses, i.e. pulses that alternate in polarity. With voltage peaks in the hundreds to 1kV range.

    Mike

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