RCD and Non RCD sockets

Discussion in 'Electricians' Talk' started by seavigil, Jan 20, 2004.

  1. seavigil

    seavigil New Member

    If I have A ring on a RCD and a radial of the main isolator for fridge 7 freezer in the same room, what is the acceptable method to prevent someone coming along at a later date and moving the fridge and then plugging a flymo into the vacant socket. Appliances need to be able to be unplugged and not hard wired direct to the fcu.

    I thought about a fcu feeding a 15a round 3 pin outlet, or a normal looking 13a plug with a non standard earth pin.

    Would the first option be ok with the regs.

    Cheers
    DJW
     
  2. The Trician

    The Trician New Member

    Not quite sure what you mean by ring & radial - do you mean that only the ring is protected by an RCD and that the radial circuit feeding the freezer is fed by an ordinary MCB? If so, then a way round it might be to change the 13A skt on the radial, which I am guessing is feeding your freezer, to a fused connection unit (or fused spur as we useed to call them) This would prevent a) your freezer being accidently being unplugged, and b) anyone plugging another appliance into it.
    Hope this helps.
     
  3. The Trician

    The Trician New Member

    Sorry - have just reread your post. It's a difficult one because you are asking people to predict future use of the radial skt. Skt outlets which feed portable equipment outside the main equipotential zone(i.e. outside the house etc) must be able to disconnect the supply within 40 miliseconds in the event of a fault. The way this is accomplished is to use a 30ma rcd unit as you are probably aware. If your freezer is in the house and it is unlikely that the radial skt is accessible enough to employ as a supply for portable equipment used outdoors then you shouldn't have a problem. BUT, as a rule of thumb, if it is sited in a garage or outbuilding then you must use an RCD. using an fcu, 15A round pin skt etc will not solve your problem.
    Sorry for the earlier misunderstanding.
     
  4. Abe

    Abe New Member

    You have described the situation I have in my kitchen. The double socket for the fridge and freezer is behind these two applicances and difficult to use for anything else - there are certainly much more convenient sockets to use for lawn mowers etc., but it is difficult to predict what a future occupant might do.

    You could consider using RCD protected sockets. The reason for putting a fridge/freezer on the unprotected side of the CU is to prevent faults on other circuits causing the power to be cut off, but it would be reassuring to know that you still had RCD protection in the case of a fault in the fridge/freezer itself.
     
  5. ban-all-sheds

    ban-all-sheds New Member

    This has been discussed before, both here and at diynot.

    If you look at what the regs say, your installation would be compliant now if you used a socket, because now you can't get to it to plug a lawnmower into it.

    You can't worry about what someone might do in the future - that would never work - if it did you'd have to use 10mm cable for every circuit in case some future fvckwit changed a breaker to 50A. Installations are or are not compliant at a point in time, there's nothing you can do to make sure that they can never be changed to a state of non-compliance in the future.

    The future could bring two changes.

    1) You move the F/F. Then your installation no longer complies, and it would be your responsibility to make it so.

    2) You move out. Then someone elses installation doesn't comply, and it is their responsibility to sort it out.

    When I rework my kitchen, my plan is to put the F/F on a non-RCD radial that has 1 socket on it. As it'll be behind the F/F, and in use, I would argue that it is no longer a socket "which may reasonably be expected to supply portable equipment for use outdoors". If/when I move house, I will disconnect the circuit at the CU. It will then be entirely up to the next occupant to decide whether to provide it with RCD protection or not.
     
  6. seavigil

    seavigil New Member

    b.a.s.,
    Point taken. I was thinking along the lines of the Electrak sockets (Farnell 538-085) but they're a bit pricey at £15 each.

    I also agree that a fcu would be the ideal option but I understand that service engineers sometimes refuse to mess with 'fixed appliance'. I am also curious what implications part P would have if you bought a new fridge and wanted to connect it up.

    just out of interest, would it be legal to fit a Schuko socket protected at 13a in the UK.

    I have always wondered how they fit the flush mounted Schuko's, do they have corresponding wall boxes the same as we do or are they a bit more primative . Personally I would prefer them to the clumbsy plugs/sockets we have here any way.

    DJW
     
  7. lensman

    lensman New Member

    Point taken. I was thinking along the lines of the
    Electrak sockets (Farnell 538-085) but they're a bit
    pricey at £15 each.

    If you're willing to spend £30, then replace the MCB in the consumer unit with an RCBO. Would allow for all future use of the circuit, and also safeguard any spurs that might be attached to the circuit in future. Also less work to fit than a FCU or even an RCD socket.
     
  8. seavigil

    seavigil New Member

    Thanks lenseman,

    I am already putting 2 RCBO's in for the two house rings, This radial in 4mm will have fridge/freezer running of it without RCD protection, at the end of this run there will be a RCD fused connection unit feeding a SWA cable to the greenhouse to run a heater, which is mission critical in the winter so I dont want to risk having anything else feeding off the same RCD.

    The problem is that the utility room is also where the back door is, so any conventional socket could reaonably be used to feed outdoor appliances (no worktops or units to hide the socket behind). Although I agree with b.a.s. I'm also inclined to err on the side of caution.
    I should add that there will also be 2 spare double sockets on the RCD protected ring available.

    My thoughts were that if someone has to fit a non standard plug to their outdoor appliance to plug it into a non RCD protected socket, takes it outside and then chews up the cable etc, I have done what I can to prevent accidental use of that circuit for outdoor use and it has to be a deliberate act on the part of that person to place themselves at risk.


    MK also do some non standard plugs&sockets with a T shaped earth pin but otherwise similiar to a standard fused 13a plug. I havent been able to find a price for these yet with all of the online suppliers I usually try.
    I'll try N&Eyre next time I'm passing.

    DJW
     
  9. RH

    RH New Member

    Why not just get a Red (or similar) coloured socket and put a sticker on it that says "Not RCD Protected" That way as long as the sticker stays readable, anyone plugging any external equipment into the socket does so having being warned of the risk.
     
  10. The Engineer

    The Engineer New Member

    As earlier said, use a fused connection unit unswitched.
     

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