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VIRTUAL ELEX SHOW IET PRESENTATION

John Peckham
Good afternoon All


As the IET have not been able to do face to face Elex shows the organisers of the Elex shows have come up with the idea of a virtual Elex show. The IET are keen to contribute to the virtual show and are going to film a webinar using the same sort of format as the live shows.


Following the live show format the IET are going to present 2 topics. The chosen topics from the feedback from the live show audiences are PME earthing and bonding and EV charging.


So if you were in the live audience what questions would you like to ask? Post them on here and I will feed them back to the IET presenters to answer in the Q&A session?


The downside is no free bacon roll I am sorry to say!


JP

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  • 0
    AJJewsbury:

     
    A wide ranging test commissioned by Myenergi showed that out of 10000 open pen situations 10% resulted in dangerous voltages from car to ground that would not have been detected by voltage measurement only.

    To play devil's advocate, I might obsever that only a little worse than the 7% failure rate for RCDs (including those in TT systems that are totally relied upon for ADS).

     

    And when viewed with the 5 s disconnection time permissible in some cases, or 2 s for TT, and the fact that protection against electric shock isn't guaranteed for a percentage of adults anyway ....


    "Is that the whole story?"

    Is that a suggestion that the N voltage during a broken PEN event isn't likely to stable - rather than just being a single voltage for the duration it's more likely to be bouncing all over the place - so quite likely to be outside of that "10%" sooner or later, and as long as the device latches off and requires a manual reset, is likely to detect most events, if with a small extra delay.


       - Andy.


    Yes, very perceptive. That's definitely part of the story.


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  • 0
    AJJewsbury:

     
    A wide ranging test commissioned by Myenergi showed that out of 10000 open pen situations 10% resulted in dangerous voltages from car to ground that would not have been detected by voltage measurement only.

    To play devil's advocate, I might obsever that only a little worse than the 7% failure rate for RCDs (including those in TT systems that are totally relied upon for ADS).

     

    And when viewed with the 5 s disconnection time permissible in some cases, or 2 s for TT, and the fact that protection against electric shock isn't guaranteed for a percentage of adults anyway ....


    "Is that the whole story?"

    Is that a suggestion that the N voltage during a broken PEN event isn't likely to stable - rather than just being a single voltage for the duration it's more likely to be bouncing all over the place - so quite likely to be outside of that "10%" sooner or later, and as long as the device latches off and requires a manual reset, is likely to detect most events, if with a small extra delay.


       - Andy.


    Yes, very perceptive. That's definitely part of the story.


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