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Ovens on cooker ccts

Farmboy
In domestic kitchens, what do you think of the practice of connecting ovens to 32/40A cb cooker ccts via dual cooker connection outlet plates? For example, along with a 6kw hob, a 2.5kw oven is connected via a 1.5mm2 3 core h/r flex? One view is that it's acceptable because the flex can't be overloaded and the cb provides s/c protection for the flex, nor would it be coded on an eicr.


F
  • 0
    There is also the point that instructions for ovens often state that it should be on a !6A circuit (as opposed to, say, 10A) - meaning that is the amperage required for it to work properly.


    People think this means it must have a 16A OPD which is actually not what is being said.
  • 0
    4a1a668bd3952acb55848e42551e8203-huge-20200225_165556.jpg

    No tools required, I removed the cover and the fuse carriers with my fingers. 


    Spot the cooker circuit that supplies the 2.8 kW double oven in the kitchen, it's in there if you look carefully. 


     I have actually pulled the perished rubber insulated cable out. 


    A job for the morning. 


    Andy B.
  • 0

    Sparkingchip:

    So you want appliances specifically manufactured for the UK market. Because people in the UK don't want to upgrade outdated electrical installations in their homes. 

     




    If that is meant for me, then no, they do not have to be. I would like people to understand.  

  • 0

    geoffsd:

    Well, I disagree because I do not think you are correct.

    If there is no difference between the internal wiring of ovens and cookers then demanding lower OPD ratings for ovens is not valid.


    Nothing to do with polo wrappers, the ovens are sold in the UK therefore the manufacturer knows about 32A circuits for cookers.




    Trust me, they don't ... and don't care !




    Why do you not suggest cookers should be on two 16A circuits as they would be in Europe?

    To design a cooking appliance that cannot be connected to a standard UK 32A circuit without extra protection is negligent.




    To assume that an old electrical installation (or old electrical installation practices) may not require changes (to be re-purposed if existing circuit) for a modern appliance is, in my view, a huge step.




    If we are talking about ring circuits then they know it will have a 13A plug; to demand a 16A OPD is also negligent.




    As above - only we do that here,and we're not talking about an appliance that's suitable for a plug in this particular case, if it takes more than 13 A (in the UK). In the EU, a B16 is not required and they have no fuses in the plug. The manufacturer has no real choice here - an appliance that's "pluggable" in the rest of Europe is sometimes not "pluggable" in the UK because of the missing 3 A.




    If we are talking about cooker circuits then they know it might be 32A which is apparent by the terminal links and instructions for cookers.




    Not so, as above






    You seem to be confusing the fixed wiring and appliance wiring and clutching at straws - I thought the problem was affording 16A protection on 32A circuits.




    Not confused, it's clear to me.




    If a cooker is alright on a 32A circuit then so is an oven. If you think a larger flex on the oven is required (it likely isn't) then that is a lot easier than down-fusing a cooker circuit - especially for two ovens.




    Nope, as above, the appliance may be suitable as "pluggable" elsewhere in the EU, but not in UK because of our 13 A fuse. This drives the fixed appliance solution, and as such also drives the unsuitability of the B32 circuit (either direct on ring, or radial)




    The OPD is for protecting the fixed wiring, not the appliance. If a manufacturer demands a lower rated OPD than the normal circuit OPD for the product  then it is not fit for purpose.




    That's not true for fixed appliances. As I've said the standards require the manufacturer to state what they need.




    There is also the point that the manufacturer's instructions often state what they believe are the regulations in the UK rather than actually required for the product.




    Agreed - check discrepancies with the manufacturer or use another product.




    The mention of 3A fuses and isolators which are not required for the same products in Europe being an example.




    A leading bathroom extractor fan requires a 1 A BS 1362 fuse to be used in the connection unit. I know a lot of electricians don't fit anything less than a 3 A in the connection unit (if any fusing down from the lighting circuit is used at all). "Common installation practice" does not, however, always equate to "safe installation practice".




    The mention of an RCBO in your previous post is also obviously not definitive - unless you think an RCCB would be unsuitable.




    RCCB would not provide protection against overcurrent due to a fault between live conductors (L-N for example). RCCB's may be used for fault protection (L-E faults) of course.

  • 0

    geoffsd:




    Sparkingchip:

    So you want appliances specifically manufactured for the UK market. Because people in the UK don't want to upgrade outdated electrical installations in their homes. 

     




    If that is meant for me, then no, they do not have to be. I would like people to understand.  


     




     

  • 0

     



    RCCB would not provide protection against overcurrent due to a fault between live conductors (L-N for example). RCCB's may be used for fault protection (L-E faults) of course.


     




    You know that is not what I meant.


    The MIs  you said specifically called for a 25A MCB or RCBO therefore they are not correct.

  • 0
    If people did not buy products from certain manufacturers because of difficulties of complying with their installation instructions you would assume that the manufacturers would then adapt the product and/ or amend the instructions. 


    So maybe installers are at fault for cobbling up an arrangement that works rather than ensuring strict compliance with the installation instructions or declining the job letting the manufacturers get away with being silly at times with their requirements. 


    Andy Betteridge
  • Former Community Member
    0 Former Community Member
    But would you necessarily be dismantling fixed equipment [the Oven screwed into the base unit] to find out how it was connected?


    Well the PAT chappie does!


    Regards


    BAD
  • 0

    The MIs  you said specifically called for a 25A MCB or RCBO therefore they are not correct.



    Those instructions make sense to me - they're after overcurrent protection to protect the appliance internals and either an MCB or an RCBO (magnetic or thermal elements) provides that - an RCCB alone doesn't.  I might wonder why they don't like fuses - but perhaps that's just down to a lack of a 25A rating in the common series.

     

    If the equipment is to be permanently wired, then, EVEN IN THE SAME PRODUCT STANDARDS the manufacturer is required to state the acceptable installation method and protective device(s) that are acceptable, if this is important for installation. So I'm not sure where this part of the argument is coming from?



    That's good. So in the earlier example where the manufacturer's instructions didn't mention any maximum OPD rating, we should be safe to assume that a, say 32A MCB, would be acceptable.


       - Andy.
  • 0

    perspicacious:
    But would you necessarily be dismantling fixed equipment [the Oven screwed into the base unit] to find out how it was connected?


    Well the PAT chappie does!


    Regards


    BAD




     

    I have done four inspections and tests so far this week, I took the built in ovens out in two of them to have a look how they are connected, because I had doubts about how the quality of the installation and one requires improvement.


    So not always, but definitely it there’s reasonable doubt.


    Andy Betteridge

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