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Who from the IET is working with the government to allow <800W inverters to be 'plugged in'?

Steve Nixon76

The UK government made the following announcement at the end of March (www.gov.uk/.../government-to-make-plug-in-solar-available-within-months) regarding Balcony Solar/Plug-in Solar. The following section features in the 'Notes To Editors' at the end of the announcement.

"The government will work with the Energy Networks Association, DNOs and Ofgem to update the G98 distribution code and wiring regulations BS 7671 to allow UK households to connect <800W plug-in solar panels to domestic mains sockets, without the need for an electrician and with tailored safety standards."

So who is the government working with at the IET/JPEL64 to make these changes to BS7671? Or is the government simply going to bypass the IET and make amendments willy nilly?

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    In respect of BSI committee work (BS 7671 is developed by a committee jointly managed by the IET and BSI, but that follows the BSI rules for developing standards) specific discussions in committees cannot be shared. Similarly, content of standards and draft standards can only be discussed when they are published, or made available as drafts for public comment.

    Would those rules prevent someone confirming whether a committee (or indeed which sub committee) had been asked to consider a particular request or requirement?

    The comments on RCD operation seem somewhat unclear to me. Mark started off taking about a certain type of RCD that the Germans had the foresight to drop many years ago (which I take to be AC types) - but the article says "But some older RCDs were never designed for electricity flowing back into the circuit" - but bi-directionality is a completely different feature - and not one universally found even in the latest RCDs. I suppose we should add in single pole switching RCDs (mostly RCBOs) where the local generation isn't separated from Earth when the RCD trips, so the shock hazard persists until inverter shutdown - again a problem that isn't mitigated by ensuring your installation is up to current standards.

       - Andy.

  • 0 in reply to AJJewsbury
    AJJewsbury said:
    Mark started off taking about a certain type of RCD that the Germans had the foresight to drop many years ago (which I take to be AC types)

    BS 4293? ;-)

    Even if you have an RCBO, what happens if somebody touches the line conductor of the same final circuit when it is exporting? If it is not bi-directional, the imbalance between L & N will not necessarily be sensed.

  • 0 in reply to Chris Pearson

    It will trip from an earth fault there there if the only NE bond is the one at the incoming main - I agree it won't if there is also an NE bond at the inverter.  So long as the inverter has anti-islanding that cuts off its output when the connection to the grid is lost, the bidirectional thing is moot, or at least no worse than a spinning down motor that carries on generating for a bit after the supply has gone.

    Mike

  • 0 in reply to Chris Pearson

    what happens if somebody touches the line conductor of the same final circuit when it is exporting? If it is not bi-directional, the imbalance between L & N will not necessarily be sensed.

    Why shouldn't it see the fault just the same? With a N-PE link only on the grid side a L-earth fault on the load/local-gen side there will be an imbalance just the same - only difference is that the N coil will carry the "extra" rather than the L. 

    We seemed to survive for many years with fixed-wired PV systems designed where "the public supply shall be considered the source as PV installation shall be considered the load" without any noticeable piles of bodies. The main difference with bi-directional RCDs that I've found so far is that they have an extra contact to disconnect the test button - so resistor can't burn out if the button is held in after the device has tripped.

       - Andy.

  • 0 in reply to AJJewsbury
    AJJewsbury said:
    Would those rules prevent someone confirming whether a committee (or indeed which sub committee) had been asked to consider a particular request or requirement?

    From what is published in past international standards, and national standards up to and including the current BS 7671, it is easy to see that standards committees involved in national and international standardisation for electrical installations have been talking about the possibility of plug-in solar for well in excess of 10 years.

    AJJewsbury said:
    The comments on RCD operation seem somewhat unclear to me.

    This is not easy.

    The 'Type AC vs Type A' is a long-standing discussion.

    The 'bidirectional vs unidirectional' is far more recent, and itself has further complexities.

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  • 0 in reply to AJJewsbury
    AJJewsbury said:
    Would those rules prevent someone confirming whether a committee (or indeed which sub committee) had been asked to consider a particular request or requirement?

    From what is published in past international standards, and national standards up to and including the current BS 7671, it is easy to see that standards committees involved in national and international standardisation for electrical installations have been talking about the possibility of plug-in solar for well in excess of 10 years.

    AJJewsbury said:
    The comments on RCD operation seem somewhat unclear to me.

    This is not easy.

    The 'Type AC vs Type A' is a long-standing discussion.

    The 'bidirectional vs unidirectional' is far more recent, and itself has further complexities.

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