Cooker and Hob

[chrisbagsy]

HI
Neighbour is have new Hob (6.3KW total load) and new double Oven (6.5KW total load installed). She has been told by her electrician that she can run both from the same 30Amp designated Cooker supply. I told her they are rated in excess of 53 Amps total. and would require a separate designated supply to each from the fuse box. (Note not MCB).

Am I right or wrong?

 

[Diyisfun]

no

 

[chrisbagsy]

Which bit?

Can she wire both appliances into the cooker Radial supply?

 

[dunny123]

Applying diversity for cooking appliances, you need to allow 10A for the first appliance, + 30% of full load for 2nd appliance, so if you allow 10A for the 6.5K appliance then 30% of the 6.3KW appliance = 8.21A so a total of 18.2A is OK for a 30A supply, providing the cable sizing is adequate. If you have a socket on the CCU then allow another 5A, but still OK.

 

[Diyisfun]

There's a thing called diversity factor..dont ask me ive seen it.
She wont have all on together.

Let the electrician...do his job..I have all mine connected on 1 circuit .

 

[ericmark]

There are a number of considerations 134.1.1 says must follow manufactures instructions and most will stipulate maximum current or in other words fuse or MCB size.
314.1 refers to inconvenience and if the supply was to regularly trip than this requirement would not be met.
As it seems you are aware fuses can take well over there rated amps for a short time and especially with re-wireable fuses over time they will weaken so although may last a few weeks could still blow. Plus re-wireable fuses are required to be inaccessible by normal person so will require an electrician to change. Cartridge fuses are better but have you ever tried to buy one on Christmas Day when tradition has it the cookers do most work.
In real terms there is unlikely to be a problem and I would not think there is really anything wrong with what he has done. If that is that it was direct replacement. However if it has replaced a single unit and involved some wiring then one would look on how wiring was done and if a RCD should have been fitted if any new wires are buried and if the installation or minor works cert has been issued and it the completion cert has been issued.
In the main if an electrician issues the paper work he is unlikely to have done anything wrong if however there is a lack of paperwork then one would question as to why and if the work complied with regulations.
Eric

 

[chrisbagsy]

Gents

Many thanks for your responses. Crystal clear answers that make life easier. Never thought about the Diversity factor but more than happy with what you have explained.

Thank you

 

[hairyben]

It's allowable with diversity.

It comes down to how it'll be used- seems to me the bigger the cooking appliances & the spend the less real use they get as they're little more than show off factor for keeping up with the joneses.

If, on the other hand, it's a real working kitchen where both ovens and 3 rings are likely to be going at once it's right on the bubble- twin circuits would be desirable.

 

[BS3036]

Applying diversity for cooking appliances, you need to allow 10A for the first appliance, + 30% of full load for 2nd appliance, so if you allow 10A for the 6.5K appliance then 30% of the 6.3KW appliance = 8.21A so a total of 18.2A is OK for a 30A supply, providing the cable sizing is adequate. If you have a socket on the CCU then allow another 5A, but still OK.

Well, don't want to be picky but..

Either, 10A + remainder times 0.3, for each appliance [i.e 30.7A]

Or, 10A + (remainder of total for both appliances) times 0.3 [i.e 23.7A]

The second method is when you consider that there is no difference in usage between separate appliances and combined appliances.