How hot will it get ?

[maldin]

Hi,
I'm in the process of installing a built in oven with a microwave/cooker located directly above the oven and in the same unit. The builder has installed a standard cooker isolator switch on the wall and has left a 6mm tail to connect to the oven only, nothing for the microwave. The cable from the isolator switch is not long enough and will need to be joined. In addition there is no electrical outlet for the microwave/cooker to connect to. So as to hide all cables etc I'm considering locating a second isolator switch for the oven complete with 13amp outlet for the microwave/cooker.
To avoid installing the second isolator in a cupboard I intend to locate it behind the microwave/cooker but unfortunately this would mean that the isolator and cable from the microwave will be in a location that will be subject to the heat disappated from the oven located below. I'm not worried about maintenance, as previously stated there is already an isolator located outside of the units and the breaker and cable will handle the load. I'm concerned about the heat damaging the second isolator and/or cable from the microwave. I could at a push locate the second isolator in a unit beside the oven but my daughter is not happy about this. I'm concerned with safety not astetics. Any help or advice much appreciated.
Regards to all
Mal Dinsdale

 

[securespark]

You should be concerned with BOTH safety AND aesthetics.

What you propose is bad practice.

Let me get this right - you have a 6.00mm2/30A circuit?

You have two appliances to connect? A build-in oven and a microwave?

What are the load ratings of these?

Why do you want to fit a second (useless) isolator switch behind the appliances? Just to join cables together?

Do your sums and work out the total maximum load drawn by both appliances. If your circuit protective device and cable exceed this figure (taking into account voltage drop), then I would install a new piece of suitable cable long enough to reach a newly installed MK K5045 WHI connection box, mounted in a position where it will not be subject to heat, but will be accessible. Then run from this with the supply cables for the two appliances. If the appliance cables are subject to excessive heat (which they shouldn't be if run inside an oven housing), then use Heat Resisting.

 

[AdamW]

Not to mention you will still have the socket free on the "outside" cooker switch (assuming it is a cooker switch + socket).

Just to add something on to what Securespark said: I assume by a 6mm tail, you mean the builder has left some twin-and-earth cable free? That is not correct. The usual way to connect an oven is with a cooker outlet plate. The T&E would be buried in the wall, terminated in the cooker outlet plate. The oven is then wired into the outlet plate using cable like this.

 

[maldin]

Hi,

Sorry to confuse everyone. Ok, The builder has installed a standard cooker isolating switch on a newly plastered wall using 6mm cable and a 40amp RCB at the consumer unit.The tail coming out of the isolating switch would normally connect to a standard cooker outlet box but the builder didn't connect this. Originally I was not concerned apart from heat affecting the cable. However the Neff oven manufacturers identification plate shows the rating as 11Kw max the rating plate on the Neff micorwave/oven mounted above shows 3.6kv max. Neff literature states to attach the microwave to a 16A supply which would be correct. Unfortunately fused spurs can only be fitted with a max 13A fuse. As originally stated I have only one 6mm cable coming from the isolating switch and a 40A breaker. I also appreciate that the cooker could pull over 50A. I intended to join the 6mm cable left short by the builder in a jointing box and from the jointing box to a 13amp fused spur for the microwave. Could I still do this or should I use the 6mm cable for the microwave/oven and change the RCB to a 16A one and install a new 10mm cable for the oven with its own isolating switch and 50A breaker. Everyone I have talked to seems to think that 11KW is unusually high for an oven and also 3.6kv is unusually high for a microwave/oven combination. There is thank god already a 6mm cable, isolating switch and 32A RCB already installed for the separate hob, again a Neff and rated at 6.8KW. Any help appreciated. Incidentally Neff literature says that after installation the flexible microwave oven cable should not touch any part of the exterior of the microwavel. Various kitchen fitters I have talked to believe that this is just Neff trying to cover themselves. Could they be doing the same by rating the oven outputs much higher than they are. Any help appreciated
Regards
Mal Dinsdale