New cooker going onto current wiring

[scoobydo123]

Hi, old cooker is too small 48cm wide in a house that I have just bought. The old cooker was rated at 9kw and is run on a 6mm cable that goes up the wall under the first floor and back down to the CU. Length of cable is no more than 11M. Back at the fusebox the fuse for this circuit is 45A! I believe this is not to regs so I need to reduce this to a 32A fuse. New cooker has a max load of 9530W. Is this ok (once fuse rating is corrected)or do I need a cable upgrade.

Cheers.

 

[ban-all-sheds]

• http://www.tlc-direct.co.uk/Book/6.2.1.htm
  
  
• //www.diynot.com/wiki/electrics:mcbtocable
  
  
• http://www.tlc-direct.co.uk/Book/4.3.1.htm
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/cableselection_web.pdf
  
  
• http://www.tlc-direct.co.uk/Book/5.3.1.htm
  
  
• http://www.tlc-direct.co.uk/Book/4.3.11.htm
  
  
• http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html
  
  
• http://www.tlc-direct.co.uk/Book/8.1.1.htm
  
  
• //www.diynot.com/wiki/electrics:part-p
  

 

[riveralt]

Hi, old cooker is too small 48cm wide in a house that I have just bought. The old cooker was rated at 9kw and is run on a 6mm cable that goes up the wall under the first floor and back down to the CU. Length of cable is no more than 11M. Back at the fusebox the fuse for this circuit is 45A! I believe this is not to regs so I need to reduce this to a 32A fuse. New cooker has a max load of 9530W. Is this ok (once fuse rating is corrected)or do I need a cable upgrade.

Cheers.

9530/230 = 41.4Amps after diversity assuming there is a socket in the cooker switch = 24.4Amps.

6mm cable with no insulation in route has a capacity of 46Amps.
Cable capacity must exceed rating of the MCB.

On those assumptions a 32Amp MCB is okay as is the 6mm cable.

If insulation is involved then is a bit more of a close call.

 

[scoobydo123]

No socket on the cooker switch just a plan Double pole 45 switch. I have looked in the links supplied by ban all sheds and it appears that anything other than surface needs 10mm but they do not have an option for up a conduit/buried in wall without insulation or is it that the wall/conduit is insulation albeit a bad one. Not even sure if there is conduit or capping.

 

[riveralt]

No socket on the cooker switch just a plan Double pole 45 switch.

Then the diversity figure is reduced by 5Amps.(19.4Amps)

I have looked in the links supplied by ban all sheds and it appears that anything other than surface needs 10mm but they do not have an option for up a conduit/buried in wall without insulation or is it that the wall/conduit is insulation albeit a bad one. Not even sure if there is conduit or capping.

The figures I quoted were from the On site Guide for 6mm cable carrying capacity - reference method C - this normal includes clipped direct to the wall and/or buried in plaster or plasterboard = 46Amps
Reference method B - enclosed in conduit on a wall or in trunking etc = 38Amps
Reference method A - enclosed in conduit in an insulated wall = 32Amps

So you unless you are using Reference method A then 6mm cable and 32Amp MCB is okay.

 

[scoobydo123]

Many thanks for the confirmation. Will out the 45amp and get the 32 amp.

Thanks again

 

[cumbriahandyman]

• http://www.tlc-direct.co.uk/Book/6.2.1.htm
  
  
• //www.diynot.com/wiki/electrics:mcbtocable
  
  
• http://www.tlc-direct.co.uk/Book/4.3.1.htm
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/cableselection_web.pdf
  
  
• http://www.tlc-direct.co.uk/Book/5.3.1.htm
  
  
• http://www.tlc-direct.co.uk/Book/4.3.11.htm
  
  
• http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html
  
  
• http://www.tlc-direct.co.uk/Book/8.1.1.htm
  
  
• //www.diynot.com/wiki/electrics:part-p