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Induction Hob and Oven.

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Supply P.M.E. Ze=0.28 Ohms. Cooker circuit, 5m long, 6.00mm2 T&E. Small bungalow. Cooker circuit protected by a B32 M.C.B. and 30mA R.C.D.


Induction hob recommended to be protected by a 20 Amp M.C.B. for full power setting. Wired in 5 core manufacturers' HO5 flex. L and N cores connected in pairs of 1.5mm2 conductors. C.P.C. single 1.5mm2 core.


Oven rated at 13 Amps but 16 Amps when in very hot self cleaning mode. Manufacturers' flex is 1.5mm2 3 core.


Both appliances are connected to the 32 Amp cooker circuit.


Can 433.3.1 (ii) be applied?


Thoughts?


Is fault protection adequate?


Thanks,


Z.




  • 0
    The fault protection is perfectly adequate Z, the cables are perfectly adequately rated for the expected load, but your only possible snag could be the manufacturers instructions. Do they say a minimum 20A CPD or a maximum 20A CPD? I expect that they do not say either, and the hob takes more than 16A at full power (that is why it has a 3mm2 cable) and I would not be surprised if it takes more than 20A, so the next size up is 32A. I also assume that the instructions do not say the appliance needs 2 supplies, so a 32A circuit is obvious, otherwise the oven and hob together may run into tripping of a 20A CPD. Please explain why you are panicking?
  • 0
    The manufacturer's instructions for the last hob I installed required a 25A "fuse" - not min or max, but exactly.
  • 0

    Please explain why you are panicking?




    Hello Dave, and thanks for your reply. I am not panicking, just looking for alternative views on this subject in case I have overlooked something.


    The hob is probably designed to continental 2 phase supplies but can be adapted for U.K. single phase use. The instructions state a 20 Amp protective device is required for maximum power use.


    Z.

  • 0

    Can 433.3.1 (ii) be applied?



    Yes (but would only cover your for the wiring external to the hob/oven) - especially as there's RCD protection (so a short from part-way along the length of an element couldn't result in a sustained overload)

     

    Is fault protection adequate?



    For the external wiring - probably (but you'd have to check the PFC & MCB manufacturer's data to be 100% sure - BS EN 60898's generic energy let-though figures suggest a 1.5mm² might only be good up for MCBs rated at 3kA)


    For the wiring internal to the hob/oven then it's down to the manufacturer's instructions and the detail of their wording for overcurrent protection (recommended or required, minimum or maximum)


      - Andy.

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