Best practice ? installing single electric oven and hob

[nettie2006]

I have a Neff single oven (2.8kW) and Neff electric hob

(7kW) to install (was to be a gas hob so no planning

was done)

There is a cooker switch with 13A socket on the wall

but no apparent further terminal box. The kitchen

currently has a freestanding gas cooker with no

electric connections. The switch is apparently

connected to the consumer unit with a 30A fuse. (max

load 63A currently full with 2 x 5A & 2x30 ccts

(cooker and sockets))

The hob has a cable attached (which according to the

manual is Y type with no user service). 2 cables

6x1.5mm2 plus earth

The oven has standard terminal connections.

I also need to install a 120W extractor fan.

question 1

Can I spur both the Hob and the cooker from the same

terminal box?

Question 2

If so, could I do this without installing a terminal

box?

question 3

What size cable should I use?

With the cable on the hob being approx 10mm2 and the

total power being 9.8Kw, I reckon the hob would take

the whole 30A cct and I would need another 13A cct

for the oven.

Could the fan and hob be run from the cooker cct

(changing out the switch for one without a 13 A

socket) AND I run the oven from the 13A socket cct?



Or could you suggest other options?

I may just bite the bullet and install the gas hob I

have instead.

Finally posted after the forum troubles. Many, many thanks to the owner for doing all the hard work

 

[NuttallsSpark]

There are a couple of things you need to do

1 For the hob its below 3KW and there fore can be on the ring main in your kitchen but the large 9KW oven you have will need its own supply via a 10mm cable from the fuse box to a cooker switch then to a cooker conection unit behind your new cooker (50A) fuse.

2 If your fuse box will not alow this load your choice is to replace the fuse board ( Assuming your manweb incoming is between 80A or 100A)
Recommend a split load DB (Safer fuse Boards)

 

[nettie2006]

There are a couple of things you need to do

1 For the hob its below 3KW and there fore can be on the ring main in your kitchen but the large 9KW oven you have will need its own supply via a 10mm cable from the fuse box to a cooker switch then to a cooker conection unit behind your new cooker (50A) fuse.

2 If your fuse box will not alow this load your choice is to replace the fuse board ( Assuming your manweb incoming is between 80A or 100A)
Recommend a split load DB (Safer fuse Boards)

The oven is 2.8kW

The Hob is 7kW

Total is 9.8kW sorry for confusion.

As this is 7kW/240V = <30A for the hob I thought the existing 30A cct would suffice if I removed the 13A socket.

I'll loop the terminal box for the oven through the existing socket ring main and spur from there. The fan I'll spur from the local double socket.

Just to check this is acceptable.
Thanks for previous quick reply.

 

[NuttallsSpark]

The problem with a 7KW applience is its Spot on 30A give or take and it would be tripping all the time you want it slightly heigher to avoid this. Although diversity will apply and not all elements will be blasting out exept for say xmass day or special occations etc.

Is the fuse for the cooker a rewireable fuse? or MCB type? if its an old DB upgrade to BS 60898 MCBs as you can get 32A and that would help the circuits from tripping.

On reply tell me more about your Fuse Board plz

 

[nettie2006]

Consumer unit
Wylex
WSES63/2

with 2x 5A fused lighting ccts NB05-type 2
1x 30A fused socket cct NB30-type 2
1x 30A fused cooker cct. NB30-type 2

It has a 30mA earth leakage trip (blew one of the lighting ccts last night when a bulb blew, is this normal or should I check the earthing on the lights)
Looks oldish but has a large 16th edition wiring claim label in black on silver so I think the electrics have been looked at recently. All sockets are MK so no problem there.

 

[NuttallsSpark]

Its oldish but not that old

When the lights are on a RCD this is normal that they trip when a bulb blows. Its doing its job

back to the cooker.
It should be ok to use the old cooker unit but only use the outlet with the cooker switch only not a 13A outlet fitted too.
Fit a cooker connection unit from this isolator to be located behind the cooker for easy connections and all will be sweet.

 

[nettie2006]

Many thanks.

I can now get the floor down , cables in and units in place!

I certainly do prefer to do things myself checking my moves with others.

My previous two houses, in one a qualified electrician had left an open 45A power shower cct sitting on a loft joist wired into a nylon choc block with the terminals exposed. I found at least one fried mouse.

In another my maintenance guy had managed to flood the place and paid for a qualified electrician to replace the consumer unit and check and replace any other wiring. I got a zap from one of the sockets as I was tightening a screw and found none of the lights or the sockets had had the earths connected: all floating at 86VAC. Damn time consuming when you think it is just the one and the fault persists.

 

[NuttallsSpark]

 

[nettie2006]

sorry, been reading things back to myself.

Another ?

FROM cooker switch currently wired to a 30A fuse in the consumer unit
TO the terminal box for the Hob

is 6mm2 OK or should I use 10mm2

distance is about 1m behind plasterboard

 

[NuttallsSpark]

30A Mcb is fine for 6MM cable if its only a short run and easy to do the rewire in 10MM as this will be good for future upgrades, But its it difficult the use the existing 6MM as this will take upto 40A in perfect conditions a bit less if there not.

 

[nettie2006]

I'm guessing you're saying 6mm2 will be fine.

The board couldn't take an Amperage hike in an upgrade and running 10mm2 would be hard as the place is victorian and it's behind plaster somewhere in the hall I think.

 

[NuttallsSpark]

Yes 6MM is ok for your cooker

 

[nettie2006]

Phew!

Thanks for your patience. Off to buy any odd bits I need now.