Wiring a replacement single oven

smax71

Long story short my single oven went on the blink yesterday (Sat) and needed it for Sunday to went out and purchased a new one and went to install. Pulled out old one and found wiring a bit dubious - 6mm2 cable from cooker switch terminated in a connector block. Another short section of 6mm2 from block to hob and a flexible cable to oven. The block was covered with insulation tape.

As I wanted to get up an running and given that this set up has been in place for a long number of years I thought it will probably be OK in short term and can have it looked over later.

Opened up new oven and 1st surprise there was no flex at all with it. Is this normal? Read the instructions and it said to use a min 2.5mm2 pvc twin & earth flex - 15A min - 20A min. Not sure does this mean the flex should be 20A or 15A?

In any case I didn't have it but as the old oven similar rating to new one I swapped out the flex and connected all up as before. Turned everything on on full load for a while and checked the connections and everything OK.

However, I need to think whats best to do now. Presumably the use of the connector block, although not great looking, is not inherently unsafe. I'm not sure what rating the block has but it certainly looks bigger that the 20-50A one I have. Anyway I will just get a cooker connector unit to replace it as presumably this is a better option? However, my main issue is the fact that the oven is directly linked to the cooker switch and not via a 13A fused unit. It this very problematic in the short term? Also do you think the flexible cable which has worked fine in the previous oven for a long time (even though not connected through a fused unit) without any signs of trouble is insufficient for this purposes? I could run a 6mm2 cable from CCU to a 13A fused unit and connect the oven flex to the fused unit?

Problem with all this additional cabling and connector units is that there is very little room behind the oven to fix to wall - would it be dangerous to leave loose behind oven - presumably the rear/top of the oven casing doesn't get very hot?

I know the advice will be to get an electrician and that is probably what I will do in the near term as I have a couple of more jobs to do which I wouldn't be competent to take on. However, I thought that simply swapping one single oven for another should be a fairly straightforward job so something a DIYer like myself should be more that capable of managing!! All advise welcome. Thanks

Risteard81

I'm afraid unenclosed block connectors are considered inherently unsafe and in fact immediately dangerous. Insulating tape is not sufficient as an enclosure and also provides no strain relief. This needs connected up properly by a competent Electrician.

I would advise that you contact a REC to sort this out for you.

2011

Suitable junction boxes are available for joining 6 sq. cable such as the one shown here:



However as you have discovered every join on a cable is a potential point of failure.
Therefore it would be preferable to wire from the cooker directly to the cooker switch.

Work such as this should only be carried out by a competent person, if in doubt my advice would be to get an electrician.

smax71

Risteard81 wrote: »

I'm afraid unenclosed block connectors are considered inherently unsafe and in fact immediately dangerous. Insulating tape is not sufficient as an enclosure and also provides no strain relief. This needs connected up properly by a competent Electrician.

I would advise that you contact a REC to sort this out for you.

Thanks for advice and I wouldnt argue with it but I will have difficulty getting an electrician in over the next couple of weeks due to work commitments. As a temporary measure if I replaced the connector block with a CCU would I reduce the risk of a problem arising or would I be better off also putting in a 13A spur for the oven, leaving the units loose at the back and getting an electrician to tidy up later when if for other work?

smax71

Just to update. I bought a cooker connector unit and 2.5mm2 flex and replaced the existing set up. The ccu was supposed to be designed for 2 6mm2 cables but in reality I found it difficult to fit the 6mm2 hob cable & 2.5mm2 flex for oven. If I was doing I again I would buy the units that have 2 separate outputs.

Its funny but the lad at the electrical wholesaler was almost incredulous that a new oven would come without a flex and that the instructions advised it should be protected by a 13A fuse. He said all separate hob and oven set ups are connected together via a ccu and properly protected by the 32A breaker.

Anyway what's more interesting to me is that the original flex on the 20 year old oven I was replacing was a 1mm2 flex and this did the job perfectly for all this time. I'm not sure how it was wired to the hob originally but certainly this 1mm2 lead spent anything up to 10 years connected to a hob via an exposed connector block and onwards to a 32A cooker switch using 6mm2 cable without any difficulty.

Will have an electrician coming on to do some work shortly and will ask him to give the cooker a once over but does anyone think that the set up I now have is substandard in the meantime?