Purpose of a cooker switch?

Discussion in 'Electricians' Talk' started by rogerk101, Dec 9, 2019.

  1. rogerk101

    rogerk101 Screwfix Select

    The UK and Ireland are the only countries I know of where most houses have a cooker switch.
    Personally I've never turned one on or off ... nor would I. Whether changing or repairing the cooker, I would always turn it off at the consumer unit. I would never consider it safe to work on a cooker just by turning it off at the cooker switch.
    They may have had some purpose back in the day of fuses, but what purpose do they serve nowadays?
    Is there any requirement to install one or would my new kitchen installation be legitimate without one?
     
  2. KIAB

    KIAB Super Member

    Many years ago at a previous place I had a fire in the kitchen which was gutted,& the cause was a faulty cooker switch, even though it was switched off,it was still passing current to the cooker.:eek:
     
  3. There is no requirement in the regs to have one, however if the manufacturers instructions say to fit one,
    then fit one.
    Just using the mcb to switch off will not give you double pole isolation,
    as double pole mcb use is very rare.

    Personally I always fit one.
     
    BillyBobToo likes this.
  4. Comlec

    Comlec Screwfix Select

    Switch off both. The cooker switch is a double pole switch so is a better means of isolation than the MCB.
    There is no such requirement in the regulation.
     
  5. MGW

    MGW Screwfix Select

    Some considerations,
    Not found a device allowing the cooker isolator to be locked off, I do however have devices to lock off a MCB.
    Most UK consumer units do not have twin pole MCB's so they can't be used to isolate with TT earthing.
    The cooker isolator is twin pole and visible by anyone working on the cooker.
    Where the cookers own controls are where in the event of a fire you can't operate the isolator assuming mounted to one side of cooker allows one to switch it off quickly.

    I think location is a big thing, in mothers kitchen where the consumer unit for kitchen is mounted next to back door at a height where a wheel chair user could access it then really no need for a cooker isolator, in event of fire I would turn off power when passing the CU as I leave the house. But in this house the fuse box was between the ceiling and the roof, standing on a ladder you could stick your hand up and turn off whole power to house, removing fuses was possible but not sure if you could get them back in, and to get to it, one has to leave the house got down a flight of steps, and go into the flat under the house, so even now not some thing one can do with any speed.

    Even mothers house main CU under the stairs, only because there was a second CU for kitchen only was that really an option. My other house fuse box is in the garage, so to switch off first you need to find key for garage door.

    So there may be situations where the CU/fuse box is in the kitchen at a height one can reach even if in a wheel chair where you could get away without the cooker isolator, but if the CU/fuse box is either in another location or at a height where all can't access, then it needs an isolator positioned to one side of cooker so in the event of fire you can still reach it.

    OK my Belling stand alone cooker has heat sensors and will auto switch off in the event of a fire, the induction hob is very unlikely to cause a fire with all the safety features, where it turns off if left unattended, or pan removed etc. One reason why I would not have gas, after Ronan Point they were banned in many high rise buildings, they to my mind are only allowed because of history, if some one invented them today they would be banned everywhere.

    And yes electric far safer than gas even with out a local isolator, however I have experienced a cooker fire, my mother sent my then young sister to turn off the ring, instead she turned on the eye level grill and there was a load of washing on top of the grill, it was right next to door, and I was able to use a shovel and carry the burning cloths outside, with the controls also eye level I could not turn off grill, and with isolator behind cooker could not turn off isolator either, and so yes being directly behind cooker the isolator did not help, once cloths outside then I could turn it off, but to empty rubbish from under stairs could not have turned off fuse box either.

    However next to electric cooker was a solid fuel cooker, only way to turn off was to drop the fire bars and rake out the fire, one reason for a quarry tiled floor, and yes I have carried out burning coals when the water supply failed and fire had to be put out quick.
     
  6. Bob Rathbone

    Bob Rathbone Screwfix Select

    The 'tradition' of installing a cooker control unit arises from the regulations concerning Exclusive circuits that supply one fixed appliance. Examples are, immersion heater, night storage radiators, on peak room heaters on their own final circuit, electric showers and the electric cooker. These local switches serve as local isolators, functional switches and emergency switches, hence the need for the cooker unit to be not more than 2mts from the cooker or cookers. Just because the regulations do not specifically request a cooker control unit does not meat than it is not needed. Regulations are a general guide to professionals, not 'Electrics for dummies', we have to apply them as we see fit.
     
  7. Comlec

    Comlec Screwfix Select

    Tradition, best practice, good design, ‘it has always been the way’ does not make for a requirement.
    That is what @rogerk101 asked. So to answer the original question - the kitchen installation would be ‘legitimate’.
    Unless I have missed something.

    Note. I am about to do exactly the same thing as the customer does not want any hideous unnecessary switches above the counter top.
     
  8. Manufacturers instructions.
     
  9. Draetsir

    Draetsir Member

    "UK and Ireland" was mentioned. In the south of Ireland there actually is a requirement to fit isolators.
     
    Deleted member 11267 and KIAB like this.
  10. There should be here too.
     
    Draetsir likes this.
  11. Comlec

    Comlec Screwfix Select

    Help us all out and post and example.
     
  12. First and only one looked at, page 4. An omnipolar switch is required.
    http://docs.hotpoint.eu/_doc/19511748401_GB.pdf
    All manufacturers will more than likely be the same, do the job properly, fit a cooker isolation switch.
     
  13. Comlec

    Comlec Screwfix Select

    Or a two-pole RCBO
     
  14. Tony Goddard

    Tony Goddard Screwfix Select

    Our 110v friends across the pond have a special socket for cookers so they can be unplugged for servicing - the idea is not a bad one as it makes it easy for the consumer to plug and play - however they have such a convoluted set of regs that they actually have 3 different styles of cooker socket!!
     

    Attached Files:

  15. MGW

    MGW Screwfix Select

    I have seen many times 2 meters stated as maximum distance isolator to cooker, it does seem there is some regulation requiring an isolator, however I don't know which regulations requires them. Part B or M or some other standard, we are given the 1/3 rule for drilling beams, it is not an electrical regulation but we need to comply with it.

    I was under the impression the isolator was in case of fire, which seems a little strange as then there would be a min and max distance from appliance as clearly if directly behind the appliance you could not reach it in the case of a fire. This document refers to Part M and it states
    What I am not sure of, is can it be mounted on the wall behind kitchen units? Try it yourself, sit on a chair, and try reaching the switch, has to be wheel chair accessible and I would question if you can get close enough to a switch in a wheel chair if there is a kitchen counter between you and a switch on the wall?
     
  16. grimer

    grimer New Member

    I've found this page because I've just experience the same issue. A faulty British General 45amp 'black nickel' cooker isolation switch was passing current when 'off'. The LED was flickering and my tester was detecting current from 10cm away from the outlet and the cooker cable.

    Not good. Not good at all.
     
  17. Bazza

    Bazza Screwfix Select

    Wonderful. You have either:
    1. Discovered wireless electricity
    Or
    2. Used a faulty tester, or one of those hopeless magic wand things. Use a proper two probe voltage test device, or a multimeter.
     
  18. spinlondon

    spinlondon Screwfix Select

    Used to be a requirement up until at least the 14th edition:
    14th editionA.29
    Every stationary cooking appliance shall be controlled by a switch separate from the appliance and
    within 6 feet of the appliance. Where two stationary cooking appliances are installed in one room, one
    switch may be used to control the two appliances provided that neither appliance is more than 6 feet
    from the switch.

    16th edition
    476-03-04 Every fixed or stationary appliance which may give rise to a hazard in normal use
    and is connected to the supply other than by means of a plug and socket-outlet complying
    with Regulation 537-05-04 shall be provided with a means of interupting the supply on load.
    The operation of the means of interupting the supply on load shall be placed as not to put
    the operator in danger. This means may be incorporated in the appliance or, if separate from
    the appliance, shall be in a readily accessible position. Where two or more such appliances
    are installed in the same room, one interupting means may be used to control all the
    appliances.

    17th edition
    132.15.1 Effective means, suitably placed for ready operation, shall be provided so that all
    voltage may be cut off from every installation, from every circuit thereof and from all
    equipment, as may be necessary to prevent or remove danger."

    Don’t know about the 15th edition, and haven’t bothered looking in the 18th.

    Always thought having the emergency switch so close to the cooker was a bit dumb.
     
  19. Comlec

    Comlec Screwfix Select

    Even when fitted, cooker switches may not be what they seem

    Found this a few days ago

    upload_2021-5-2_18-26-14.png

    The cooker switch(with socket) above is suppled from the kitchen socket(presumably a ring) and fed from a 32A MCB. And yes that is 1.5mm flex supplying the cooker from the connection plate.

    The occupier wondered why the MCB had tripped. I wonder why the house hadn't burnt down.
     
    rogerk101 likes this.
  20. eve_963

    eve_963 Member


    Local isolation?
     

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