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O-pen devices, Overvolatge, IET-01, increasing the volatge to mitigate issues !!!!!

Dom
Good morning all, I am looking for a bit of clarity - I have some fitted chargers which are tripping the O-pen device above 253 volts, this is down to spikes with the voltages on the DNO side. When contacting the DNO they are unable to rectify the issue as its within the tolerances that they work to. I have discussed this with the charger manufacturer who are stating that their charger voltages can be upped to 256 volts. The issue I have is that this charger is not fully compliant to IET -01 and I am struggling at present to fully understand the implications of IET -01 and its relationship with Bs7671, specifically the regulation stated below.
The one thing I am having some difficulty with is the impact of over voltages on our clients with their chargers constantly cutting off, and the fact that the DNOs will not help. I am struggling somewhat to fully interpret  722.411.4.1 (V) - in regards to how manufacturers of charge points can state the increase in volatges is acceptable, is this purely based on their methodolgy in regards to the stated regulation? 
We have chargers from reputable British manufacturers with the ability to increase the voltage ranges, these manufacturers are stating that down to their interpretation of indent 5 that they can in fact do this, my issue is trying to understand if this is the case and could we implement these voltage increase, to help with the problem of tripping? Indent 5 does not specify voltage ranges, simply stating the same or greater protection as opposed to the other indents in this regulation?
I appreciate within Appendix 2 the voltages tolerances are stated as
Is it possible to work out with these tolerances if the methodology behind compliance with 722.411.4.1 (V) is met?
Thank you very much.
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  • +1

    I suspect you're not going to get a nice yes/no answer for this - as there's no clear definition of what makes such a system safe or unsafe in the first place.

    As a bit of background there was a thread about the way open-pen devices like this work - Open PEN detection for 722.411.4.1 (iv) - as you seen there are situations where the results are perhaps less than ideal anyway. Increasing the acceptable voltage range will increasing the probability of the system remaining connected in a hazardous situation,  but given the original system is not entirely perfect in the first place, whether that constitutes a significant reduction in safety is debatable rather than calculable.

    I could see an argument that if the device had some additional mechanism for reducing the risk from shock under broken PEN conditions - not just voltage measuring, but say monitoring the c.p.c. current and disconnecting immediately if hazardous shock levels were present (say >10mA), and as that wasn't compromised at all by the voltage limit change, the overall risk might not be significantly increased.

       - Andy.

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  • +1

    I suspect you're not going to get a nice yes/no answer for this - as there's no clear definition of what makes such a system safe or unsafe in the first place.

    As a bit of background there was a thread about the way open-pen devices like this work - Open PEN detection for 722.411.4.1 (iv) - as you seen there are situations where the results are perhaps less than ideal anyway. Increasing the acceptable voltage range will increasing the probability of the system remaining connected in a hazardous situation,  but given the original system is not entirely perfect in the first place, whether that constitutes a significant reduction in safety is debatable rather than calculable.

    I could see an argument that if the device had some additional mechanism for reducing the risk from shock under broken PEN conditions - not just voltage measuring, but say monitoring the c.p.c. current and disconnecting immediately if hazardous shock levels were present (say >10mA), and as that wasn't compromised at all by the voltage limit change, the overall risk might not be significantly increased.

       - Andy.

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  • 0 in reply to AJJewsbury

    Thank you very much for this Andy - and I would agree with you that there is no simple yes or no answer here. I am in a difficult posistion due to the fact we have manufacturers stating that voltages can be increased while myself as the installer is left scrambling to understand the comlexities of this decision. 

    I really feel at a lost at present, the charger I am discussing does have additional monitoring on the CPC so that is a benefit, I am still unsure how I can justify that in terms of upping the voltages - against what is in BS7671? Would you have any thought or comment on that?

  • +1 in reply to Dom

    I see that in New Zealand the have changed their supply voltage limits because of Prosumer issues from +6% to +10%, while keeping the DNO supply level at +6% to allow for back feeding from solar on longer distribution lines.

    see https://www.youtube.com/watch?v=s8RXQERPzMY "The newly announced NZ Grid Voltage Increase explained".

    This may give one view on how to explain things, even if it's not directly equivalent.

    The other option is to distinguish between a "Fault" and "Disturbance" (aka Dangerous vs Annoying).

  • 0 in reply to Philip Oakley

    Thank you very much Philip, I will have a look at that video. 

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