Cooker & Hob circuit breaker rating

Discussion in 'Electricians' Talk' started by DARREN HARPER, Nov 3, 2019.

  1. DARREN HARPER

    DARREN HARPER New Member

    I currently have an oven on a 32amp MCB circuit with 4.5mm2 cable. New build stuff.
    The oven is only rated at 3.57kw 20amp and is over protected I guess!!
    I'm upgrading by adding a 7kw 32amp Induction hob.
    Advice required please.....
    Do I need to upgrade to a 50amp MCB on the consumer unit and add a 2 module consumer unit with 20A and 32A MCB's located near to the appliances?

    Thank you and Appreciation for your help in advance.
     
  2. terrymac

    terrymac Screwfix Select

    The MCB protects the cable not the appliances. The cable size that you quoted ,how did you come to the conclusion that its the size you quoted ? If it is 6mm² t&e that would be more likely. If it is ,you can connect both oven and hob to that circuit.
     
  3. Bazza

    Bazza Screwfix Select

    And you do not just upgrade the size of an MCB.
    The MCB is there to protect the cable, If the MCB is too big then , if there is a fault, the cable can catch fire.

    if you have a new build, you should have been provided with an Electrical Installation Certificate. That will tell you the real size of the cable.
     
  4. DARREN HARPER

    DARREN HARPER New Member

    Terrymac.... Thanks for your reply.
    I wrote my post late on yesterday... You are correct, the cable is 6mm2 t&e and protected by a 32Amp MCB at the consumer unit.
    So to explain...
    I have an oven currently on the radial circuit and has a rated load at 3.57kw and a 20Amp fuse rating.
    I wish to add a new hob (currently gas) which is 7kw load rated and a 32Amp fuse rating.
    You mentioned that I could connect both appliances to the current circuit...
    Can I simply spur off the back of the current cooker switch to a second cooker switch with 6mm2 t&e??

    Cheers for your help.
     
  5. DARREN HARPER

    DARREN HARPER New Member

    Bazza.
    Sound advice. After a long day my 4mm2 description was wrong! It is 6mm2 t&e.
    I have just replied to Terrymac.

    My plan to add the hob will work great and very straight forward if I can spur off the current cooker switch to a 2nd cooker switch with a view to keeping the 2 appliances capable of being independently isolated.

    I would appreciate your comments.
     
  6. Hans_25

    Hans_25 Screwfix Select

    Better to use a Dual Appliance / Cooker Outlet Plate.

    You may run into the issue of the MCB resetting, as the load of both hob and oven is over 32Amp, actually nearly 46 amps if both are at full tilt. You could potentially get around this by replacing the 32 amp MCB with one rated at 40 amps, but should seek qualified advice on this for example if the cable is clipped direct then cable is likely OK, but not if its buried in insulation.
     
  7. terrymac

    terrymac Screwfix Select

    You would use a dual cooker connection unit ,and connect both to it. You do not need to change the MCB. The designer of the circuit has determined that the 32 amp MCB is the suitable OPD for the circuit.
    With diversity applied to your appliances potential load its perfectly adequate.
     
    DARREN HARPER likes this.

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