Installing an electric hob

[AnonymousImport]

Hi,

At the moment I have an electric oven installed and I'm just about to installed the electric hob.

What I need to know is, can the oven an hob be spured from the same socket, or does the hob have to have a seperate one?

Thank in advance

Mark

 

[loftus75]

The answer is probably no, through it's not really that straight forward. First you'll need to know what the feed to the cooker is. Is it from a standard cooker outlet, whats the wattage of the cooker and what's the wattage of the hob.The answer to your question depends on the total of these and the size cable your spurring from. If you let me know what the wattages are I may be able to answer your question. I hope this helps.

 

[AnonymousImport]

It will be from a Standard cooker outlet with 6.0mm 45Amp T+E Cable.

The cooker wattage is 2.07kW
The Hob Wattage is 5.8kW

 

[loftus75]

A good rule of thumb is, for every 1000watts used this translates to 5amps. Cookers and hobbs have what the trade call a diversity allowance so to cut a long story short; you allow 10amps + 30 percent of the total demand. This means you have 10amps plus 30percent of 7.87 = 2.361KW, translated to amps this = 11.8amps. as you have a 45amp capability you are well within your allowances to connect to that point. Hope this helps.

 

[AnonymousImport]

Thanks for that.

So just to confirm I should be able to connect the hob and the cooker to the same socket?

 

[AnonymousImport]

2.07kw + 5.8kw = roughly 8000 watts

8000 x 5amps = 40 amps

you have 45amps so you should be OK, failing that you will need to run an extra spur from the downstairs fuse spur.

All that will happen is you will find the trip switch tripping if you overload the cooker (if you have breakers) or fuse wire blowing if you dont.

You can get additional advice from your local electrical trade supplier, theyre very helpful.....

 

[AnonymousImport]

Having another look at it, the Cooker ring on the fuse box only has a 30 Amp fuse in it so it's going to blow.

Now, can I gt this changed to a 45Amp one, or does that mean replacing all the whole circut.?

 

[AnonymousImport]

If the fuse is rated at 30Amp, chances are the cabling is rated at this level also.

i.e. if the cable is rated at 30amp max and the fuse is changed to 45amp, then the cable will give in (i.e. catch fire etc.) before the fuse will.

I wouldn't take that chance!

 

[AnonymousImport]

I don't fancy my house burning down!!

Is there any way to check the exsiting cable to see what the rating is?

 

[loftus75]

You'll need to confirm the cable is 6.0mm. If you are unsure, turn off the power at the fuse box and remove one of your 13amp sockets, the cable feeding this will be 2.5 (or should be) compare the size of the 2.5mm cable with the size of the cable going to the cooker outlet, the cable going to cooker outlet should be significantly larger. If still in doubt you would be better advised to get someone that has experience of this to check it for you. Ideally you should also be certain that there is no spurs on the cable going to the cooker, if the cable feeding the cooker outlet is 2.5 there is a possibility someone may have made the mistake of spuring the cooker outlet off the ringmain, ion which case the figures you have been given will be redundant as we would not know what else is loaded on that circuit. Sorry if this has made things more complex, but safety has to be first priority.

 

[AnonymousImport]

I do appreate all your help.

I think to cable is about 4.0mm, its not quite as thick as the 6.0mm, 45Amp cable I have.

Looks like i'm going to have to get the cable running from the consumer unit to the Cooker replaced and the fuse changed.

I'm starting to hate DIY!!

 

[loftus75]

If it's 4.0mm, and my figures are right, this should be okay up to 26amps, so allowing for diverity you should be well within the load range. I suggest you keep the 30amp fuse and continue connecting. Keep in mind that is unlikely demand will reach the full capacity, hence the allowance for diversity. so when calculating, to reiterate, you start with 10amps, than add 30 pertcent of the total load, this still keeps you within the load range that you would require. Don't loose heart, we all had to learn at some timeHowever, one day when you get the chance, upgrade your consumer unit to MCB' with an RCD, it would be in your own interest. Fuses are not entirely reliable, but don't worry you should be okay if you keep the 30amp fuse. Best of luck.