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AC Type RCD No PV or Car Charger C3 or C2

Davies Gareth

For a standard domestic Install, split board with 2x Type AC main switches.

No PV or Car Chargers should this be a C3 or C2?

Thanks in advance  

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  • 0

    Yesterday's announcement from the Government: https://www.gov.uk/government/news/government-to-go-further-and-faster-in-becoming-energy-secure

    If plug-in PV is being pushed as a way forward, and these are to have a UK standard plug (although BS 1363-1:2023 Clause 5 states that the UK plug shall not be used for connecting generators) then certainly in rented homes, and in flats (rented or otherwise), for the installation to be considered safe, surely:

    1. RCDs (RCCBs and RCBOs) for socket-outlet circuits (and upstream distribution circuits if applicable) would have to be at least Type A (because of the way inverters operate, but also for the existing PV inverter standard BS EN 62109-1, this is stated as a requirement for 'pluggable type A' equipment (i.e.. with a standard plug) to be compatible with Type A RCDs; and

    2. RCDs (RCCBs and RCBOs) for socket-outlet circuits (and upstream distribution circuits if applicable) would have to be bidirectional (Regulation 530.3.201 introduced in Amendment 3); and

    3. RCDs (RCCBs and RCBOs) for socket-outlet circuits would have to disconnect all live conductors (see Regulation 551.7.1)?

  • 0 in reply to gkenyon
    gkenyon said:
    They will be happy until something does happen, it's put forward that the RCD didn't operate and that might have saved a life ... and then all hell will break loose; and it will, of course, be our fault !

    Agreed

    Therefore Product specification and/or requirement need to deal with it for the UK.  Very rare that a consumer will consult BS7671 or BS1363 while to shop on Amazon (other retailers are available)

  • 0 in reply to Sergio Fernandez
    Sergio Fernandez said:
    Therefore Product specification and/or requirement need to deal with it for the UK. 

    Not sure how the product standard could sort out some of the issues (e.g. incorrect type of RCD/RCBO, unidirectional RCD/RCBO, and single-pole RCBO)?

  • 0 in reply to gkenyon

    product standard for balcony solar could mandate an RCD plug for example.

  • 0 in reply to mapj1
    mapj1 said:
    product standard for balcony solar could mandate an RCD plug for example.

    Agreed

  • 0 in reply to mapj1
    mapj1 said:
    product standard for balcony solar could mandate an RCD plug for example.

    I think that's missed the point ... the RCD protecting other socket-outlets could be:

    1. Blinded if it's Type AC

    2. Permanently damaged by the presence of a source of energy on its load terminals if unidirectional.

    THe danger is then a fault on other appliances connected in the same circuit. In the case of item 2 above, this will persist even after the plug-in generator is unplugged ... so I'm not sure how this could be addressed by the product or its instructions for use?

  • 0 in reply to Simon Barker
    Simon Barker said:
    The average consumer will have no idea what sort of RCDs they have.

    Neither will yer average politician.

  • 0 in reply to gkenyon

    They will be happy until something does happen, it's put forward that the RCD didn't operate and that might have saved a life ... and then all hell will break loose; and it will, of course, be our fault !

    Given that in-service RCDs have a general failure rate something in the order of 7% ... aren't we in that situation anyway?

    Likewise when the householder admits they haven't pressed the T button in the last 6 months...

       - Andy.

  • 0 in reply to AJJewsbury
    AJJewsbury said:
    Given that in-service RCDs have a general failure rate something in the order of 7% ...

    Are we sure this statistic still current? Yes, I'm aware that, what is now quite a long time ago, there was a study that indicated that statistic ... but there have been a number of developments in product standards for RCDs over the past 25-30 years.

    In fact, this site proposes 97 % reliable, with an improvement if the devices are tested regularly: https://www.electricalsafetyfirst.org.uk/guidance/safety-around-the-home/rcds-explained/

    Compare that with certain unidirectional devices that are known to fail 100 % of the time if they are operated (including by pressing the test button) with a 230 V source connected to the load terminals ... 

    AJJewsbury said:
    aren't we in that situation anyway?

    So, no I don't think we are.

  • 0 in reply to gkenyon
    gkenyon said:
    In fact, this site proposes 97 % reliable, with an improvement if the devices are tested

    I really struggle with that. I suppose that it means that if RCDs are tested and are found to fail, they are replaced, which apparently improves the reliability overall.

    3% failure rate. What would you accept for the brakes on your car, for example?

  • 0 in reply to Chris Pearson
    Chris Pearson said:
    What would you accept for the brakes on your car, for example?

    Surely there are far more [orders of magnitude more] injuries and deaths due to RTAs than electricity-related incidents?

    Need I say more?

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  • 0 in reply to gkenyon
    gkenyon said:
    Surely there are far more [orders of magnitude more] injuries and deaths due to RTAs than electricity-related incidents?

    OK, bad analogy.

    How about seatbelts? In the vast majority of journeys, they provide no restraint because none is required.

    Is there any evidence that RCDs have saved lives over the past 40 - 50 years? Even if electrical fatalities have reduced, it could be for other reasons, so difficult to prove.

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