Electric Oven On Kitchen Ring

[redman]

Hello all,

My sister is in the process of buying a newly refurbished house & ive just been down to have a look around with her.

The house has been fully rewired, everything has been finished quite well, theres just the gas hob & electric oven to install.

I had a look at some of the electricians work & I noticed that the oven supply & extractor hood are on the kitchen ring circuit.

I told my sister that this may cause some problems once all the appliances are in the kitchen & powered up. 

This cicuit is a 2.5mm ring with 32A MCB. There are 4 double sockets & 2 single sockets for the oven & extractor hood.

The appliances will be (approx) : 

2300 W  - oven

100 W    - extractor hood

2200 W  - kettle

120 W    - fridge/freezer

900 W    - microwave

2150 W   - washing machine

7770 W  -  total

If everything is in use at the same time, this will be too much for this circuit.

Also, there is no means of isolating the oven, as the single socket to supply it, is behind where the oven will sit.

Is there anything in the regs that says an oven should have its own circuit ?

Im just wondering what some of you guys would reccomend in this situation, before I go any further.

Cheers.

 

[betty swollocks]

I cant see what you have described causing a problem, the gas hob ignition and extractor barely use any power. The oven is a single oven and is generally connected to the circuit via a plug with 13a fuse.

In a perfect world I would always supply an oven, regardless of power output, to it's own circuit for convenience, however life is not always straight forward, my main concern is that from what you have describe, the oven isolation is behind the oven it's self, meaning you couldn't unplug it without first removing the oven.

Personally I would have this socket moved, perhaps to an adjacent cupboard so in the event of a fault or for service/maintenance you could remove the oven from the circuit.

 

[Technician]

There is something in the regs concerning loads in excess

of 2kW and the intent is the ring circuit not supplying a

number of loads, each of which is more than this value.

That is why Betty proposed a separate circuit for the cooker.

You could ask the guy to have a look at appendix 15 and

see what he says.

 

[Theorysparky]

seperate cct for one of these then ????

http://www.argos.co.uk/static/Product/partNumber/9086465.htm

I agree with betty  get the socket moved

if a rewire was done I would have given it seperate cct with a socket outlet

 

[SPECIAL LOCATION]

Hello all,

My sister is in the process of buying a newly refurbished house & ive just been down to have a look around with her.

The house has been fully rewired, everything has been finished quite well, theres just the gas hob & electric oven to install.

I had a look at some of the electricians work & I noticed that the oven supply & extractor hood are on the kitchen ring circuit.

I told my sister that this may cause some problems once all the appliances are in the kitchen & powered up. 

This cicuit is a 2.5mm ring with 32A MCB. There are 4 double sockets & 2 single sockets for the oven & extractor hood.

The appliances will be (approx) : 

2300 W  - oven

100 W    - extractor hood

2200 W  - kettle

120 W    - fridge/freezer

900 W    - microwave

2150 W   - washing machine

7770 W  -  total

If everything is in use at the same time, this will be too much for this circuit.

Also, there is no means of isolating the oven, as the single socket to supply it, is behind where the oven will sit.

Is there anything in the regs that says an oven should have its own circuit ?

Im just wondering what some of you guys would reccomend in this situation, before I go any further.

Cheers.

Not heard of diversity ???

Tip......

i) everything is NOT drawing full load current all of the time it is switched on!!!!!

ii) And some things are only drawing a full load current for a short period...

NOT for long durations of several hours at a time...

iii) A vast majority of a washing machine cycle it is only rotating a drum motor..

It is NOT heating water!!!

iv) stick a clamp meter on some of these appliances see what they are actually drawing!!

Then only add together the ones that are on on full load simultaneously for a duration of greater than 15mins..

that would probably be a more realistic max load

AND anyway..

32A MCB will power over 7.5kW easily..

Loads of 8.0kW showers are still running off 32A 6.0mm circuits.

 

[Technician]

Agreeing totally with SL and appx 15 draws attention to avoiding

a situation wherein the heaviest loads are close to one end of the

rfc.

That 15 minute period is informative.  Is this from a best practice guide?

 

[redman]

Thanks for your help guys,

Looks like ive overdone it with the max demand / diversity.

Im not used to doing cicuit design. I spend most of my time installing on commercial building sites, where all the cable calcs & spec are already worked out for us. 

Time to brush up on that I think.

Anyway,

my sister has spoken to the builder who did the whole refurb. He said hes going to ask the electrician to move the socket to an adjacent cupboard for easier access.

Cheers

 

[SLIPSHOD & SLAPDASH]

I only get concerned with kitchen loadings when there are seperate ovens, fridges, freezers, wash machine, driers, dishwashers, microwave & all the other plug in appliances on one ring.  If money permits i wire the fridge freezers to a dedicated circuit  and try to split the drier from the ring.