new cooker and hob question

[justin_time]

My old freestanding cooker has now gone and have a double oven and separate hob going in. The current set up is 32amp fuse back at the box to a cooker switch+single socket then down to the outlet behind the cooker. (all installed when the flat was built 15 yrs ago)

The old cooker was a 8.3kw. The new one states 5.6-6.1kw and the hob 6.3kw. The hoped for easy option of wiring both new hob and cooker to the current outlet and upping the fuse in the box is bound not to be the advised option. Its never that easy. So what suggestions do you have as to the best way to do this?

Many thanks

 

[JohnD]

Gas hob

 

[justin_time]

much prefer gas hobs but I'm in a flat and we're all electric

 

[justin_time]

Any suggestions

 

[Taylortwocities]

If you look at the max possible demand from both appliances you get around 50A. But, in a domestic situation, we can apply something that is called 'diversity'. This works on the basis that some appliances (including cookers) never draw their max current. this is because the hob rings etc will be thermostatically controlled, etc etc.

For a domestic cooker it works like this.
Take the first 10amps of each appliance at 100% demand. Add 30% of the remainder and that is the assumed demand.

Your appliances (at 240v) are 25amps and 26amps respectively.
So: for oven allow 10 amps + 30% of 15. Total = 15Amps
for hob allow 10amps + 30% of 16 Total = 16 Amps

Total using diversity = 31amps. (Less than your existing 32A limit)

Now, this is on a normal day. Come Xmas morning you may have all the rings on, plates warming, goose in the oven and you could hit a problem.

If I was designing this I would put in new 10mm feed from the board with 45A contact breaker and I suggest you do the same. If this is totally impractical then its just possible that you can run both appliances on the existing circuit and fuse.

REMEMBER, the fuse is there to stop the cable catching fire in the event of a fault or over current situation so you MUST NOT just increase the fuse rating without increasing the cable size.

Hope this helps

TTC

 

[securespark]

TTC. You forgot to add 5A for the socket outlet...

 

[JohnD]

Surely no-one uses those horrid things any more? I thought all the users had become extinct due to their habit of draping the kettle lead across the hot rings?

 

[Taylortwocities]

TTC. You forgot to add 5A for the socket outlet...

Thats what comes of answering forum q's at midnight.

Yes add 5A to the diversity total if you have a socket on yr cooker switch but I'd suggest you swop it to just a switch as you are more than tight on yr current limits!

TTC

 

[justin_time]

Cheers guys. Never use the single socket for the reason JohnD says - the leads just get in the waay so will swop it for just a single cooker switch. Just happened to be what was installed by the original builders.