Cooker on ring main....

[Newbie90]

Hi all,

A friend of mine is looking at replacing his existing built in oven (not cooker as stated in title ) with a new one.

The existing one is on a plug top and is connected to a standard single 13a socket on the house ring main. There is no isolator either.

The new one is 3.5 kW. The manufactures instructions say that the minimum cable size should be 2.5mm and the minimum fuse size 15a. Also it does not have a plug top so needs t&e.

I know the load isn't massive but I've always know cookers to be on their own circuit.

Is it acceptable to keep the cooker on the ring main or does it need a new circuit from the consumer unit installed?

If keeping it on the ring main, do I need to install an isolator or is that a requirement for new builds/new installations?

Thanks

Thanks

 

[Brendan976]

I will put a 2.9 kw oven on a ring at a push, anything over that goes on its own circuit .
Ben

 

[telectrix]

install a new radial 2.5mm on a 16A or a 20A MCB. FCU to oven. otherwise, you run the risk of overloading the RFC when kettle/toaster/washer/microwave/oven etc. are all or several on together.

 

[dan86]

I'd run a 2.5mm radial on a 16a mcb just as Tel said. that way you're doing what manufacturer says

 

[Newbie90]

The only problem is, the kitchen had been fully tilled with built in units pretty recently! Obviously if its gotta be done, then it's gotta be done!

What about replacing the single socket with a 13A R.C.D spur?

 

[telectrix]

so, come from above, behind wall cupboard , cut out and replace a couple of tiles after chasing down to below worktop. then tell the numpty to do things in the correct order next time ( after he's paid, of course ).

 

[Newbie90]

He has only just bought the place and it was refurbed a few Months ago.

Was hoping the new oven would be a straight swap.

Obviously a new circuit would be ideal. An RCD spur could be the alternative?

 

[amlu]

3.5 kW its 15 amps. that is leaving another 17 amps free to use on 32A ring.
diversity applied you may get lucky with that, inform the customer that in the worst case
of overload the breaker will trip. they will have to learn to live with it or call you again for separate
circuit and some tile smashing.

 

[amlu]

He has only just bought the place and it was refurbed a few Months ago.

Was hoping the new oven would be a straight swap.

Obviously a new circuit would be ideal. An RCD spur could be the alternative?

rcd spur off existing ring? if place is been done then existing ring should be already rcd protected. if is not then
is different story.
for isolation means 20A dp switch above the worktop, and cooker outlet behind the oven will do the job.

 

[Farmelectrics]

On its own circuit for me

 

[Newbie90]

The ring is RCD protected and the socket is part of the ring and has not been spurred off.

The existing cooker has worked fine with no tripping issues.

Maybe worth keeping the set up the same as the existing and if it causes any tripping problems then put a new circuit in.

 

[davethsparky]

Tell them they should have found out what size (in terms of power) oven they could have before they bought it! If they can return it and get it replaced with a more suitably sized one then hey presto problem solved

 

[whazza22]

What's the likelihood of a 3.5kW oven pulling more than 13 amps?

Could always replace single socket with a 13a switched fused spur. Then the fuse would blow if it achieved more than 13a.

If it causes problems then a new circuit would be required.

Any thoughts on this?

 

[davethsparky]

Firstly the plug will have the same 13a fuse in it so no advantage to changing to a switch fuse.

Secondly how much power it uses depends on the oven format. If its a single oven element of 3.5kw (very unlikely) its very different to a 2kw oven element and 1.5kw grill element which can't be switched on at the same time!

 

[Engineer54]

As usual, ...what's the betting this 3.5KW is the connected load, rather than the maximum usable load!!

Is there no 45A Cooker control unit that you can utilise to supply power to this oven??