advice on cooker wiring

[goldie]

Just after thoughts and advice please.
I was asked by a customer my thoughts on a situation within some flats they own where there are single ovens (2kw load) wired directly to the electric hob above (5.5kw load) protected by 32amp mcb
They are wanting to replace the ovens (like for like) and I advised that the hobs were to stay wired on the 32amp dedicated circuit but a socket/spur to be installed so the ovens can be fused at 13 amp as per manufacturers instructions and to avoid overload on 32 amp circuit with hob and oven on full load and also maybe possible overcurrent risk,
I suppose diversity should be taken into account so maybe not much risk of overload.
I am debating with myself whether or not this extra work does need to be done and would like any reasons for and against if poss.
Obviously if this was a new install I wouldn't have designed it in this way but this is existing and would like to weigh up reasons for and against installing supply via 13 amp fuse for oven, also don't want to give client wrong advice if this is the case.
I just feel that on one hand although not fused at 13 amp there is local isolation available but on the other hand I would always try to use protection as near as poss to the power rating of the appliance.
Am I right in thinking that for example a loose termination on the oven wouldn't be an issue with causing the fuse to blow as this causes s higher resistance and less current to flow? Or would this possible fault increase the current and therefore be a fire hazard as the oven wiring would overheat before tripping 32amp mcb?
Just trying to think of all possible outcomes for these two scenarios.


Thanks in advance.

 

[LankyWill]

Easy

1.5mm hr flex and a 13A plug top

 

[Richard Burns]

Any standard cooker / oven /hob circuit will be a 32A radial so manufacturers should really be aware of this and design their equipment accordingly.
If the oven is supplied with a plug and the manufacturers instructions indicate that this fusing is required then the provision of a socket instead of the hard wiring would be a good idea.
The overload scenario has been down to death and whilst it may be possible it is very unlikely.
The fault protection is the key issue, is the oven suitably protected with a 32A MCB for fault protection?
I would say probably as the disconnection on full fault current would be likely to be sufficiently quick to not require a larger cpc. However the individual circumstances of the circuit should be checked to confirm this.

 

[goldie]

Thanks for your response Richard.