Installing a Neff oven

pearsad · Posted: Sat Mar 17, 2012 10:43 am

Hi,

First post on the forum so please go easy if I miss out some info!

I am going to be wiring a new Neff oven to the existing cable that the old oven was connected to. I have removed the wires from the old oven and all 3 have a metal end attached which were slid over metal plates to make the connection (as far as I can see).

Looking at the back of the new oven there are 2 small metal plates that look like the Live and Neutral would slide over as in the old oven. The earth however just has a screw so I think I will need to cut this metal clip off, strip back the wire, and wrap around the earth screw before clamping down.

Just wanted to make sure I am going about this the right way before I do it.

(out of interest, I woul have just paid for them to connect it for me but apparantly the cable isn't quite wide enough to meet their specifications to install. The guy said it would be fone to do myself though, he was basically just covering himself).

Any help would be much appreciated.

Many thanks
Adam

Taylortwocities · Posted: Sat Mar 17, 2012 10:50 am

What size is the "COOKER" fuse in your fusebox/consumer unit?
What size is the cable coming from the wall to the cooker? There is a very rough guide here http://www.diynot.com/wiki/electrics:cable_types:flatpvccables
What is the rating of the oven - there will be a rating plate inside the door or on the back of the oven.?
IS it a single or double oven?
The existing cable, how does it attach to the wall?

pearsad · Posted: Sat Mar 17, 2012 10:59 am

Thanks.

The fuse is 32A
The cable is 2.5mm
The only rating I can see is 'A' if that's what you need
It's a single
The cable goes behind the kitchen units and tiles and goes to the switch on the wall.

chivers67 · Posted: Sat Mar 17, 2012 11:11 am

Just to clarify one 2.5mm on 32 amp you say?

Have you the model number if you can't find the wattage rating of the cooker?

pearsad · Posted: Sat Mar 17, 2012 11:17 am

The guy said it was a 2mm cable and looking at the link and measuring the cable that seems to be the one. The fuse in the fuse box for the cooker is a B32 so 32A.

The model is a B14M42N0GB which had a total connected load of 2.85KW according to the website.

holmslaw · Posted: Sat Mar 17, 2012 11:41 am

chivers67 · Posted: Sat Mar 17, 2012 11:46 am

Have you any other fuses you could use as Holms has pointed out?

sparkiemike · Posted: Sat Mar 17, 2012 12:19 pm

holmslaw wrote:

If your original installation was 2.5 cable on a 32A fuse, you have been lucky, a fault could have caused a fire.

You should replace the 32A fuse with a 15 or 16A.

What kind of fault - the new oven is rated at 2.65kW, the old oven was probably about the same, this load is unlikley to result in the 2.5mm T&E carrying any overload current, see reg 433.3.1.

Unless it is a very long circuit (more than 30m ), fault current will probably be OK even with a 30A fuse.

EFLImpudence · Posted: Sat Mar 17, 2012 12:54 pm

Does that mean it's an oven on a ring final spur?

chivers67 · Posted: Sat Mar 17, 2012 1:23 pm

sparkiemike wrote:

holmslaw wrote:

If your original installation was 2.5 cable on a 32A fuse, you have been lucky, a fault could have caused a fire.

You should replace the 32A fuse with a 15 or 16A.

What kind of fault - the new oven is rated at 2.65kW, the old oven was probably about the same, this load is unlikley to result in the 2.5mm T&E carrying any overload current, see reg 433.3.1.

Unless it is a very long circuit (more than 30m ), fault current will probably be OK even with a 30A fuse.

Iz ≥ In ?

holmslaw · Posted: Sat Mar 17, 2012 3:49 pm

sparkiemike · Posted: Sat Mar 17, 2012 4:21 pm

That is because this location is does not present a fire risk or risk of explosion - it is not a garage forecourt or saw mill.

The reason for the "probablies" is that we don't have the full picture!

I can't be 100% sure of the size of the old oven
I don't know the EFLI values to be sure of fault protection.

Nevertheless I don't see the 2.65kW oven overloading the 2.5mm T&E.

holmslaw · Posted: Sat Mar 17, 2012 4:30 pm

sparkiemike · Posted: Sat Mar 17, 2012 8:00 pm

I will concede that its not the way I would design it, however if I came across it during an inspection I would not immediate condemn it as a fire risk.
Just about any electrical load generates some kind of heat and constitutes a fire risk if not designed properly.

However To quote the reg in question

Quote:

433.3 Omission of devices for protection against overload
This regulation shall not be applied to installations situated in locations presenting a fire risk or risk of explosion or where the requirements for special installations and locations specify different conditions.

As I interpret it is applies to locations or special installations, not all fixed wiring or electrical appliances.

The second part that I was reffering to does allow for the ommission of overcurrent if the type of load means that the cable will not be overloaded.

Quote:

433.3.1 General
A device for protection against overload need not be provided:
...
(ii) for a conductor which, because of the characteristics of the load or the supply, is not likely to carry overload current, provided that the conductor is protected against fault current in accordance with the requirements of Section 434
...

So if I have "misunderstood" the above reg then please explain your interpretation.

Of course MI for the oven may specify the cable size and overcurrent protection in which case all the above is hypothetical

holmslaw · Posted: Sun Mar 18, 2012 12:01 pm