Advice on compliance with regulations for new kitchen and general wiring question

Hi all, a couple of things:

1. We are looking at getting a new kitchen - live in old house with COB/brick/thatch construction for info. The kitchen fitter sent his electrician a pic of the current Consumer Unit which is a Wylex split load RCD, plastic case and he wants to replace it. The house wiring contains a mix of old and new wiring colours, but I had an EICR about a year ago to comply with my insurance requirements and it passed OK. Is there any good reason for requiring a change? He said something, via the kitchen fitter, along the lines of conforming with current regulations back to the fuse box. Is this really the case as I didn't think so from what I've read? I'm a chartered engineer, but only work on low voltage stuff so need to check what the situation is with people familiar with the regulations working on this day in, day out before I start querying this if it goes ahead.

2. One of the circuits has a 10A MCB feeding a junction box just below the CU which feeds through to some outside lights (old halogens no longer working via armoured cable outside) and a 13a socket just below the CU. The location of socket means it's really just used to plug in the hoover. Where does this stand with regard to the regulations? i.e. a 10A limited MCB feeding a 13A socket and outside lights? For info, I am intending to replace the old halogens with newer LED types so hardly any current there, but looking more closely at it I came to notice this. 

Thanks, James.

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  • New/replacement socket-outlet circuits require arc fault detection devices (AFDDs) and surge protection (SPD)

    As I read the regs unless it's a Higher Risk Residential Building (e.g. >18m tall), House in Multiple Occupation, purpose built Student Accommodation or a Care Home, there's no requirement for AFDDs. There may be a recommendation, but that's not quite the same as a requirement, and I've yet to meet anyone who actually installs AFDDs commercially when they don't need to.

    I agree an SPD would likely be required, but that can be retrofitted without a complete CU change (space and aesthetics permitting) - either in a separate enclosure fed from the existing CU, or even in the supply tails (e.g. https://www.tlc-direct.co.uk/Products/WYREC2SPD.html)

       - Andy.

  • As I read the regs unless it's a Higher Risk Residential Building (e.g. >18m tall), House in Multiple Occupation, purpose built Student Accommodation or a Care Home, there's no requirement for AFDDs.

    There's a recommendation, though.


    As some see it, 'do it unless there's a good reason not to' (because you might be asked 'why' if something goes wrong?

    Kitchen ... may be full of  heavy current-using equipment, and almost certainly a fridge-freezer (in which the fire was, on the balance of probabilities, started at Grenfell) ... perhaps a good reason to use AFDD (in the opinion of the person designing the modifications to the installation)?

  • and almost certainly a fridge-freezer

    And most AFDDs don't work for currents below 2.5A ... which most domestic fridge freezers won't draw - so little chance of an AFDD spotting a series arc there. It might spot an parallel arc - but then an RCBO is likely to too. There again the fault might have been simple resistive heating, which nothing would have spotted.

    Cooking appliances (or showers) might be a better bet - but there's not even recommendation for AFDDs for those (unless plugged into a socket...)

       - Andy.

  • nd most AFDDs don't work for currents below 2.5A ... which most domestic fridge freezers won't draw -

    A parallel arc might temporarily or intermittently, though ????

    Cooking appliances (or showers) might be a better bet - but there's not even recommendation for AFDDs for those (unless plugged into a socket...)

    Perhaps have a look at reports on statistics, but if memory serves, a lot of cooking appliance fires are not (initially) related to electrical faults in the appliance itself. I believe (but we would need to check up) that top of the list of appliances after cookers (ovens/hobs) and microwaves that might be associated with fires are 'white goods' (in no particular order washing machines, tumble dryers and fridge-freezers).

  • A parallel arc might temporarily or intermittently, though ????

    The AFDD demos I've seem seem to suggest they only respond after several seconds of arcing (no doubt to reduce unwanted tripping) - so it feels likely an RCBO will have got there first for parallel arcs.

    Perhaps have a look at reports on statistics,

    My thought behind showers/cookers was the common reports of terminals burning out in shower pull switches and (perhaps less often) DP switches for cookers.

      - Andy.

Reply
  • A parallel arc might temporarily or intermittently, though ????

    The AFDD demos I've seem seem to suggest they only respond after several seconds of arcing (no doubt to reduce unwanted tripping) - so it feels likely an RCBO will have got there first for parallel arcs.

    Perhaps have a look at reports on statistics,

    My thought behind showers/cookers was the common reports of terminals burning out in shower pull switches and (perhaps less often) DP switches for cookers.

      - Andy.

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