16A ovens - best solution in

Discussion in 'Electricians' Talk' started by Spark19*, Oct 14, 2021.

  1. Spark19*

    Spark19* Member

    Replacing a single oven with two new ovens. The current oven is (as many are) supplied by a 6mm radial and protected by a 32A, 30mA RCBO at the consumer unit. The two new ovens each state they need a 16A fused connection (total kW is only 3.5kW Max for both ovens so the existing 6mm cable is absolutely fine). The property already has 2 consumer units and no spare spaces. There appears to be no 16A fused spurs available on the U.K. market. Only options I can think of are to add/replace to the already convoluted consumer unit setup and run two new 16A RCBO protected circuits through the property (not very cost effective). Or add yet another consumer unit into the kitchen off the 6mm radial, effectively splitting the existing 32A circuit through a further 2 16A MCBs and on from there. It all seems a bit **** though. Anyone else come across this issue and any suggestions?
     
  2. Dan dan the man

    Dan dan the man Active Member

  3. Spark19*

    Spark19* Member

    I did come across those outlets. The part that I’m struggling with is that to the letter of the regs the ovens should be installed to the manufacturers instructions. If I connect them both straight through to that outlet (even if they are both on separate 45A rated cooker switches beforehand) the oven cables after the outlet (and each appliance) is not protected by a 16A fuse as specified, but a 32A fuse at the consumer unit. So unless im missing something, im not really following the regs?
     
  4. Comlec

    Comlec Screwfix Select

    From the 18th Edition


    134.1.1 134.1.2
    ERECTION AND INITIAL VERIFICATION OF ELECTRICAL INSTALLATIONS Erection
    Good workmanship by one or more skilled or instructed persons and proper materials shall be used in
    the erection of the electrical installation. The installation of electrical equipment shall take account of manufacturers' instructions.
     
  5. Roys

    Roys Screwfix Select

    I went from one oven to two ovens when I changed the kitchen. I used one of the Click dual outlet plates as mentioned above. I never altered the circuit so it is still a 32A RCBO protecting a 6mm cable to a single isolator. As far as I was concerned the 32A RCBO is primarily for the cable protection. Certainly didn’t invalidate the warranty as I have already had a warranty repair carried out.
     
  6. Spark19*

    Spark19* Member

    Agreed Comlec - so am I back to the original options? I can’t think of another solution. It’s either ensure two 16A RCBOs and run from consumer unit (massively disruptive in this instance) OR a garage type consumer unit in the kitchen with two additional 16A MCBs, both giving the protection the manufacturer specifies?
     
  7. Spark19*

    Spark19* Member

    Roys - maybe I’m overthinking this but surely the fused protection the manufacturer specified is also for the cable they have attached to each appliance (guess only rated at 16A max) and to a lesser extent the appliance itself?
     
  8. Roys

    Roys Screwfix Select

    Haven’t done the 18th and not been in the trade for a number of years so obviously I am a bit dated, but fairly certain the regs used to say that the protection in a consumer unit was only to protect the fixed wiring, don’t mind being corrected if I’m wrong. I take on board what you are saying about each appliance being fused down to 16A but in my mind if that was an issue then they should have their own internal protection.
    Interesting though and I look forward to hearing other opinions.
     
  9. Spark19*

    Spark19* Member

    Roys - don’t get me wrong ... I’d prefer you to be right save me a right load of hassle...
     
  10. Jimbo

    Jimbo Screwfix Select

    I asked the exact same thing a week or two ago. The consensus was that no 16A MCB was needed. I also contacted NEFF, in my case, who replied “we cannot comment on electrical installation except what is provided in the installation instructions”.
     
  11. Roys

    Roys Screwfix Select

    I certainly don’t lose out on any sleep worrying about it. As far as I am concerned it is a safe installation but as I say I am willing to listen to any constructive comments to the contrary.
     
  12. Spark19*

    Spark19* Member

    Well it’s reassuring that no-one has yet said YOU MUST SOLVE this or you may be in dire straits I’m warming to the suggestions of not solving it and sticking with the 32A.
     
  13. terrymac

    terrymac Screwfix Select

    The oven can't draw more current than its rating ,at 3500 watts that's around 14.5 / 16 amp depending on supply voltage. So it needs to be hard wired to a circuit with that current carrying capability. The MCB or RCBO is there to protect the fixed wiring ,not the appliance. A fault current caused by a failure in the appliance would cause the OCPD to trip regardless.
    Wire both to a dual outlet plate.
     
    rogerk101 and (deleted member) like this.
  14. Jimbo

    Jimbo Screwfix Select

    My understanding is that these problem appliances from NEFF are supplied with flexible cables and some kind of socket on them, “the appliance must only be connected with the power cable supplied”.
     
  15. Spark19*

    Spark19* Member

    That is enough consensus for me. Thanks all!
     
  16. terrymac

    terrymac Screwfix Select

    Eh ? Come again ? What " some kind of socket " would that be ,tell more I am intrigued.
     
  17. Jimbo

    Jimbo Screwfix Select

    It says “Connect the power cable to the back of the appliance (listen for the click)” so that rules out C19/C20 I suppose.
     
  18. Jimbo

    Jimbo Screwfix Select

  19. Ad_g

    Ad_g Active Member

    That was the approach our electrician went for. We had a gas hob and double oven, which we moved to a flex-induction hob and two single Neff 16A ovens.

    Old 32A feed now supplies the hob and a second was run from the consumer unit to a second consumer unit in the cupboard next to the ovens with a 16A MCB for each oven.

    Diversity rules meant we could have just had everything on the old MCB but the new feed was simple in our case and it was only just ok. I did expect a dual outlet but the electrician was happier with the dual 16A feeds.

    All been working without issues for 3.5 years and don’t notice the consumer unit hiding in the cupboard.
     
  20. Jimbo

    Jimbo Screwfix Select

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