Fitting New Single Oven

Discussion in 'Electricians' Talk' started by COYR, Dec 30, 2013.

  1. COYR

    COYR New Member

    Hi,

    I've posted here before but it's been a while......

    Anyway our Single Electric Oven has given up the ghost, element has gone for the second time and due to age we have ordered a new oven. In fact we have purchased the latest version of the model we had before as we were happy with it and it will of course just slot in nicely.

    I removed the broken oven tonight to check how it was connected. We had a new kitchen fitted earlier this year and was unsure how the old oven had been connected. Our new oven comes fitted with a 13 amp plug.

    Our old oven is connected in to a Cooker Connection Unit together with the seperate ceramic hob. This is controlled by a Cooker Switch beside the Hob which runs back to our Consumer Unit. I plan on just connecting the new oven in the same way after removing the plug. Just looking for thoughts on this as I am unsure whether our fitters connected the oven and hob up correctly?

    I've attached a photo of how things are connected at the moment. The white cable is the old oven and the black cable is for the hob.

    Thanks
     

    Attached Files:

  2. seneca

    seneca Screwfix Select

    If the new oven came with a pre-fitted 13 amp plug it means that the makers want it to be fused at 13 amps so you should really run a cable from the connection unit to a 13 amp socket, preferably somewhere that's accessible, in an adjacent cupboard for instance.
     
    mad4kitchens and FatHands like this.
  3. Daibando

    Daibando New Member

    If the oven has a 13A Plug its designed to be protected by a 13A Fuse. If you remove the plug and wire directly onto the cooker connection unit it is likely protected by a 32A MCB or 30A fuse. By the way the wiring to the junction box is poor. The inner insulation should not be outside the box.
     
    mad4kitchens and FatHands like this.
  4. unphased

    unphased Screwfix Select

    Fixed load. Oven cannot overload the flex. It would be perfectly safe cutting the plug off and connecting it back in as per the old oven. What are the other wires in the junction box? Like Daibando said they should be enclosed. Single insulated cable is not supposed be exposed.
     
  5. seneca

    seneca Screwfix Select

    I thought that too UP but didn't comment as I thought they might be double insulated singles and didn't want to complicate things for the OP. I'd still rather see the oven connected via a socket or fcu though, as the makers fitted a plug. Technically though no need as it's a fixed load as you said.
     
  6. I suspect COYR was more concerned that the new oven - being possibly of a lower maximum power that the old one - would not have adequate protection, being covered by whatever MCB is in the CU. It certainly won't be a case of the oven overloading the flex, assuming the grey cable is a 6mm or possibly even just 4mm.

    So, although it isn't ideal for a sub-13A appliance being protected by a - what? - 20A? 30A? MCB - what the 'ell.
     
  7. COYR

    COYR New Member

    Hi,

    thank you for all the replies which have been very helpful. The cable that goes into the Junction Box is the original cable (black/red) from the Consumer Unit. As far as i can make out a cable then goes from the Junction Box to the Cooker Switch (which is combined with a 13 amp socket) and then back down into the Cooker Connection Unit. We had a new Consumer Unit (with 30 amp MCB) fitted at the time of the Kitchen install (fitted by an Electrician and not the Kitchen Installers). A number of new sockets were also fitted and these were checked and certified by the Electrician however he would not have seen the wiring as the old Oven was in situ when he did his work.

    I like the sound of fitting a 13 amp socket as having thought about it more I am also concerned that if I remove the manufacture fitted plug it may cause warranty issues if ever there was a problem! Unfortunately I would be unable to fit a socket within an adjacent cupboard and would just have to tuck it down the back of the oven housing (like the Cooker Connection Unit was).

    I take it a 1.5mm twin and earth cable from the Cooker Connection Unit to the 13 amp socket would suffice? Is there any minimum length of cable from the Cooker Connection Unit to the 13 amp socket? Finally I take it a single 13 amp switched socket in a mounting box would do?

    Sorry for all the questions and thanks for any guidance offered. Happy New Year to you all.
     
  8. unphased

    unphased Screwfix Select

    Hi mate. Happy New Year to you, too. You can make a tidy installation out of this if you are prepared to make some changes. :) The wiring that goes in to the junction box needs to be altered so that the single insulated conductors are contained wholly within an enclosure. Ditch the existing junction box and create a new one. What I would recommend is to get yourself a 47mm deep single surface patress and a blanking plate and a 60A connector block. A 60A connector is huge and will allow you to connect large wires with ease. Mount the surface patress on the wall behind the oven, preferably at a height where it will be clear sufficiently from the back of the oven. Use this to create a deep junction box. Take the old red/black cable in to the box so that only the grey sheath is outside the box and cut the conductors to a suitable length, say around 50mm and terminate these in to the 60A connector block cut off of three. Then take the new 6mm2 cable and joint it on to the 60A connector block which will reconnect the cooker control back up again. Then take another 6mm2 cable from the 60A connector block and put this in to a single socket which you can mount on a surface patress to plug your oven in to. 6mm2 because it keeps the cable sizes the same in the junction box and they are all okay on the 32A mcb. Put the blanking plate on and the jb is then complete. Then connect just the hob on to the cooker outlet plate on its own. If you take your time I don't see why you couldn't make a tidy job, and all this will end up better and safer than the present bodge.

    Good luck!
     
  9. COYR

    COYR New Member

    Hi thanks for that Unphased. The only issue I have is that the Cooker cable from the Consumer Unit to the Junction box has had the outer sheath stripped back until just before it is plastered into the wall so unfortunately there is no give and it appears I have to work with what I have got. Could I use a 6mm twin and earth cable from the Cooker Connection Unit to the 13 amp socket?
     
  10. unphased

    unphased Screwfix Select

    Can you possibly position a new patress over the wiring where it is buried in the plaster? You need to get this bodge removed from the set-up. Or even chop out more cable so you expose more of the sheath. You won't see any damage made to the wall behind the oven so chop and adapt as necessary. I wouldn't advise leaving it as it is.
     
  11. Lectrician

    Lectrician Screwfix Select

    Dig the plaster out, it's out of view anyway.

    That jb doesn't look like a 30amp one either.
     
  12. DIYDave.

    DIYDave. Screwfix Select

    Just a couple of questions on this thread whilst reading through please;

    In the photo of the cooker connection unit, what's it resting on - looks like a blanking plate ? Was this fitted to the back of the unit instead of a patress box

    You say you can't fit a socket for the oven in an adjacent cupboard, why is this , what's either side of the oven

    If you fit the oven via plug / socket, then this needs to be accessible for local issolation, will this be possible if tucked behind oven housing as you say

    You can't run a new socket in 1.5 T&E, you need 2.5mm (1.5 used for lighting circuits)

    I'm just a diy'er so I'm sure the pros can further advise - good luck
     
  13. COYR

    COYR New Member

    Hi DIY Dave,

    The Cooker Connection Unit is resting on its faceplate. It has what can be described as a "nose" on it that the cable can be run through. On one side of the oven unit is a three drawer unit whilst on the other side there is a kitchen cupboard. The wife wasn't keen on me drilling holes through our new kitchen units but I suppose I could cut off the manufacture fitted plug so it would just be two holes to run the cables into the cupboard! It has been suggested to me (not on here) that I could cut the flex for the old oven that is connected to the Cooker Connection Unit and fit a socket to that to plug the new oven in......but then again maybe not.

    The matter that prompted me to post originally was that I wasn't sure whether the Oven and Hob should be connected to the same Cooker Connection Unit. To be honest I'm thinking of calling in an electrician to sort the cables out but that's an added expense on top of an unexpected cost for replacing the oven on what I'm sure for everybody is a finacially challenging time of the year anyway.

    As a reasonable DIY'er I thought it was something I could sort out fairly simply but the more I have to change the less confident I am getting!
     
  14. DIYDave.

    DIYDave. Screwfix Select

    Hi COYR
    The cooker connection unit is really just a faceplate with terminals attached to it, this would then screw onto either a surface or flush box. Can't work out what your ccu is resting on. Only wondered as wiring to jb is very rough, other lash ups may be in place
    Yeah I know you've got a new kitchen but it's usual to cut a few access holes for pipes and cables. As long as this is kept neat and tidy then surely the mrs will be ok with this .If cupboards have got decent backs fitted, ie, thicker than 3mm hardboard, fit socket to back of cupboard using 25mm patress. Bring 2.5 T&E up behind cupboard and into pattress. As you say, cut plug off oven flex, drill "neat" 10mm hole under socket and fed through flex, attach plug. Feeding wires from back of cupboard will keep them clear of oven when you slide it into position
    It's ok being a reasonable diy'er, same as loads of us mate. It's just with electricity, it really can be a life or death situation if we do something wrong. Even when we flick the switch and it works, it don't mean that our work is safe, an installation can work but still be a potential liability. I don't mean to be rude or to preach
    with my last statement, really
    Have a safe new year and hopefully a working oven
     
  15. Phil the Paver

    Phil the Paver Screwfix Select

    Surely you can't do any of the above as a diyer, based on the fact that your not part P registered, this sort of electrics fall into part P, because it in the kitchen.
     
  16. DIYDave.

    DIYDave. Screwfix Select

    I have a feeling that a kitchen is no longer classed as a "special location" so not sure if part p still applies here. A pro surely will advise. The regs can be difficult to interpret but I do agree that a lot of DIY electrics should not happen.
    So saying, some "pro" electrics are pretty shoddy as well
     
  17. Phil the Paver

    Phil the Paver Screwfix Select

  18. unphased

    unphased Screwfix Select

    Phil your link is out of date mate. The revised Part P (amendment 2 I think it is), excludes kitchens as a special location.
     
  19. Bazza-spark

    Bazza-spark Screwfix Select

    Unles you're in Wales UP. The changes don't apply here yet/
     
  20. unphased

    unphased Screwfix Select

    I'm not in Wales, Bazza. The amendment is Part P 2013 and excludes kitchens from the notifiable part. I know they don't cover Wales yet.
     

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