Installing a Rangemaster 90 Electric cooker.

[Canon Hall]

Hi,

I am in the process of buying a Rangemaster 90 combined ovens and hob.

The ceramic hob is rated at 7.43Kw. The 2 ovens are rated at 7.57Kw giving a total max. electrical load of 15Kw

My fuse box is pre-historic and already quite full with a seperate trip switch. Without going into details, it is better and much less expensive to leave well alone.

Am I in order to install a seperate fuse box for the cooker, upgrading the trip switch if necessary? If so, what would I need please?

1. Cables. 10 meter run.

2. Fuse box.

3.trip switch.

4. Isolation switch (switches?)

Would appreciate any help.

 

[tom1]

whats circuit is on your old oven on

6mm

30/32 amp?

 

[Apache]

Hello and welcome to the forum.

I have to say I love Guernsey. Went there on holiday 2009 and loved every minute. Thinking of going back this year. Where abouts are you?

 

[Larnacaman]

As far as the 2 ovens are concerned, ...i doubt very much if you will see anything like 7.54KW. There will be elements that cannot be utilised at the same time, such as main oven element and grill element. So check again to get the real Max load. Then you can apply the age old diversity factor, to get a much better understanding of what current your cooker will ''actually'' draw in normal usage!!

 

[Badger]

well ive just worked it out if the oven does use 15kw i one hit thats approx 60 amps which is huge! more like i reckon the max it will use at any one time is 10kw which is approx 40 amps!

 

[Apache]

Diversity anyone?

 

[Badger]

thats y i said it will only use approx 40 amps during use due to elements switching on and off.

 

[Apache]

thats y i said it will only use approx 40 amps during use due to elements switching on and off.

Thought it was 10A +30% remainder so 26.5A

 

[Larnacaman]

First 10A + 40% +5A if there is a socket outlet on the cooker control unit ....

No-one knows the real Maximum connected load, as the OP has only given the total KW value of the complete cooker!!!

Edit.... +30% ...hit the wrong key ...lol!!! Good for cooking appliances upto 15KW ...of which there are actually very few!!!

---------- AUTO MERGE Post added at 03:47 ---------- Previous post was at 03:37 ----------

So 6mm cable, which will probably be already be installed and a 32A MCB, again probably existing, should suffice on a 10m run of cable....

 

[ProDave]

This size of all electric cooker I would be looking at 10mm cable and a 40 or 50A MCB. I have seen one before on a 6mm 32A circuit and I was called because the customer who had just installed it themselves to the existing "cooker point" complained it tripped frequently when both ovens and a few hob rings were on.

In the OP's case, if he describes his CU as "pre historic" I would leave that alone, and fit a new "Shower CU" to feed the new cooker outlet, unless you are getting an electrician to do the work when the most sensible solution may be a CU change.

Of course one important question, is this ALL electric? I ask as it's a little unusual to describe the hotplate rating and oven rating separately. If all electric then you just usually get a total rating. I've only seen separate ratings quoted for dual fuel cookers.

 

[Larnacaman]

Dave,

6mm cable is more than ample for a run of just 10 meters. If in the unlikelihood of a 32A MCB tripping, then you can always replace the existing MCB with a 40A one....

That cooking appliance diversity formula has proven it's worth, ....that it works!! It's been around now for some 60 years for cooking appliances/loads upto 15KW.

By the way, most cooking appliances ovens/hobs and the like normally give individual ratings for each element. What the buggers don't normally tell you is that some of those elements can't be used in conjunction with other elements. So in reality, a 15KW cooker comes down to around 12KW as a full connected load in many cases....

 

[Canon Hall]

Thanks for all that fast advice. I should have mentioned that the new rangemaster is in a different location to a built in oven that it is replacing so there has got to be a new cable run. I quite understand the problem of finding the realistic max. load, the answer is I just don't know and can't understand how to find out!

Diversity! Do I need one new cable or three, one for each oven and one for the hob?

If I fit a new shower MCB is there a choice of how many fuses it has, how many do I need bearing in mind that it and a 40a CU would be in parallel to the existing set up which I intend to leave well alone as it was probably installed in the age of magic and electrickery the house dating from 1625.

Answering the question of where in Guernsey I live,it is in the Vale very close to St Sampsons and The Bridge. You would not have liked Guernsey so much this year as the summer was awful and we are now having the coldest winter that I remember!

Regards