3.4KW oven

[Taylortwocities]

Why do you say that? It is simply not the case.

Maybe I have been misunderstanding the requirement for fixed equipment (ie an oven) connected to a ring final. The diagram in my regs book has only one option and that is an FSU with a (maximum) 13amp fuse,
I see no option otherwise to spur from a ring final to a larger protection device that is larger than 13amp please educate me.

 

[winston1]

I don't understand.

Surely the FSU was there to protect the flex running from it to the old 3.4Kw oven? I have no idea what size flex was previously used.

I am now using some rated at 27amps (2.5mm) but I am concerned that the 13 amp fused is under rated for the maximum load. I don't want my mum complaining that each time she runs the oven at max, it trips the 13 amp fuse.

It won't. 13 amp fuses don't rupture at 13.001 amps. They will take considerably more.

 

[EFLImpudence]

I don't understand.
Surely the FSU was there to protect the flex running from it to the old 3.4Kw oven? I have no idea what size flex was previously used.

Yes, it was but it was too small for the load.
13A fuses (in plugs and FCUs) don't like being run at 13A all the time - let alone even higher.

I am now using some rated at 27amps (2.5mm) but I am concerned that the 13 amp fused is under rated for the maximum load. I don't want my mum complaining that each time she runs the oven at max, it trips the 13 amp fuse.

Yes it is underrated however it is not going to trip at 14A or 15A; it will just overheat slightly until it makes its connections loose and overheats more.

From my understanding of what I have read here, the primary purpose of fuse protection is to protect the cable supplying the device. I assume that the oven has internal safety features that protect the internal wiring.

That is correct.

There are various methods allowed for protecting the spur (the cable NOT the FCU).

These range from "omission of overcurrent protection" where the appliance (not sure if applies to microwave) cannot cause an overload (although there are other things to be considered), to
the use of appropriately rated overcurrent protection as you have done with the MCBs, to
the use of higher rated cable (4mm² 37A) for the spur so that it may be used on the the 32A circuit without further protection.

 

[EFLImpudence]

Maybe I have been misunderstanding the requirement for fixed equipment (ie an oven) connected to a ring final. The diagram in my regs book has only one option and that is an FSU with a (maximum) 13amp fuse,
I see no option otherwise to spur from a ring final to a larger protection device that is larger than 13amp please educate me.

Well, that there is only a maximum of 13A fuse is surely the problem and the reason for that.

Do you not think if there were a 16A fuse (and holder) it would be just as safe - or the use of adequately rated cable for the 32A circuit?

 

[EFLImpudence]

Not fixed equipment - but there is of course the unfused spur to a double socket only protected by two 13A fuses.

 

[EFLImpudence]

Has it been asked and answered already?

I don't suppose it is the case that the microwave cannot use all of its 3.4kW at once and so would be quite happy on a plug and socket.

 

[opps]

Has it been asked and answered already?

I don't suppose it is the case that the microwave cannot use all of its 3.4kW at once and so would be quite happy on a plug and socket.

I haven't asked previously, and BTW, the oven is 3.6Kw, the old one was 3.4Kw- the title of the thread, which mentions 3.4kw was an error on my behalf.

The oven is now up and running. It hasn't had the initial burn in yet.

With regards to maximum power consumption, I noticed that in fan assisted mode it can reach 275°C, that is far higher than any other fan assisted oven that I have come across (from memory, my combi oven is 220°C in fan mode.) I would guess that the max draw would be microwave (900w) plus top and bottom heating. In all honesty, I doubt that she will ever use that option.

As an aside. I purchased 2m of 2.5mm flex, thinking that I would need to wire the machine up. I didn't realise that it is supplied with a proprietary plug and flex which fits in to the back of the oven. I did notice that the outer diameter of the supplied cable is thinner than the (surplus to requirements) 2.5mm flex that I picked up. I didn't inspect the actual cores though.

Anywho, I just want to thank you and all of the others that took the time to contribute.