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  • Cooker electrics
  • spursn17
    Member

    Following on from my induction hob question I’m now looking at the practicalities of replacing the hob, and possibly the oven.

    Our hob (knackered) is rated at 7.2kw, and our oven (Neff, still going strong) is rated at 5.1kw, this is all on a 30amp breaker with 6mm wiring.

    I’m assuming that if I replace with the same wattage or less it should all be good, if so how much wriggle room have I got if the new hob (and maybe oven) have a higher wattage rating? And also, is 7.2kw enough for a decent induction hob?

    stevextc
    Member

    It shouldn’t just be the breaker that’s 30A, the wiring should be as well and the isolator switch…. so you’re running about 2/3rds of 30A.
    I can’t see the exceeding that but I’d not screw about with that kind of current… (and I screw about with lots)

    spanishfly
    Member

    From your post its seems you have the hob and the oven on one 30A circuit, therefore assume
    Currently 12300w maximum demand divided by the supply voltage of 230v = 53.4 A

    By applying diversity as per IET BS 7671
    “The first 10 A of the rated current plus 30 % of the remainder of the rated current plus 5 A if a socket-outlet is incorporated in the control unit”

    I have assumed you have no socket outlet.
    10A + 30% 0f 43A = 22.9A load after diversity applied

    So you have potential of raising the loading but I would try to resist as although 6mm has circa 40A + capacity, this is based on its condition and a well ventilated install (this can be severally curtailed in the cable is with thermal insulation/buried in the wall) 7kw -8kw is more than enough for any kitchen hob.

    I hope this helps

    7kw -8kw is more than enough for any kitchen hob.

    MOST hobs. I’m fitting one in a few weeks at 9.6kw…

    spursn17
    Member

    Thanks spanishfly, that’s about what I worked it out at (after reading up on it), I just needed it confirming by someone who knows what they’re doing!

    The cable is in good condition, and it runs around the eaves so it’s in a pretty cool area, but it does run in insulation from the ceiling to the cooker switch (about 5′ long). Will that hurt it if I put an extra 0.7kw through it?

    spanishfly
    Member

    700w adds 3A prior to diversity, bearing in mind the likely hood of all rings being utilised at max simultaneously is going to me rare (Christmas day maybe….) I would not lose sleep about it.

    FYI TW & E 6mm max current capacity clipped direct is 47 A

    TW &E Capacity

    spursn17
    Member

    Thanks very much. STW is always the best source for electrical info, much better than Lambretta forums or modelling one’s! 😀

    I came here expecting to read about Charge’s new Cooker electric bike, disappointed it’s actually about cookers.

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