Change of electrics required for new oven?

[EFLImpudence]

Based on this - would you still say 20 or 16 mcb to replace the 32??

As a theoretical question, the answer would be "It depends on lots of thing".

In your case just instal the lowest rated MCB that will let your appliances work properly.

 

[Dave123456789]

Funny Cos people are saying do 20/25! lol

Dunno how electricians actually pass exams with so much different thought

 

[EFLImpudence]

Because we are not there,

only going on contradictory information and

don't want to tell you anything which might be wrong or dangerous.

 

[EFLImpudence]

Please read your own posts #1 and #6 again.

 

[Michaelsf90]

The mcb is to protect the cable. The current carrying capacity of a 2.5 cable is 24A. The closest mcb size to that is 20A. If you linked the socket and the microwave with a 2.5 cable you have made it from a 2.5 to 5.0mm2. Do you know what I mean? The reason a ring main can go on a 32A is because it is 2 x 2.5 cables making it 5mm2 in total. Because it's been split to single 2.5s it can only carry 24A maximum. So yes it needs to go on a 20A unless you put a 2.5 to link the two cables. With the loadings you have statd the cable isn't going to be overloaded and is fine. But I'd put a 20A mcb in then the circuit is covered

 

[AndyPRK]

Well the max cable rating is 27A.

But a 20A is a sensible compromise for protection and being able to change oven at a later date.

 

[DetlefSchmitz]

The mcb is to protect the cable. The current carrying capacity of a 2.5 cable is 24A. The closest mcb size to that is 20A. If you linked the socket and the microwave with a 2.5 cable you have made it from a 2.5 to 5.0mm2. Do you know what I mean? The reason a ring main can go on a 32A is because it is 2 x 2.5 cables making it 5mm2 in total. Because it's been split to single 2.5s it can only carry 24A maximum. So yes it needs to go on a 20A unless you put a 2.5 to link the two cables. With the loadings you have statd the cable isn't going to be overloaded and is fine. But I'd put a 20A mcb in then the circuit is covered

Words fail me...

 

[Michaelsf90]

I wasn't far off with 24A haha it was a good guess. Why do words fail you detlefschmitz

 

[flameport]

And yes I forgot to mention sorry - that from consumer unit - there’s a 4 or 6mm cable for about 1 metre that then splits off into
the 2.5 kitchen ring cable
The 2.5 radial oven

If the consumer unit is only 1 metre away, surely it would be quicker and easier to just change it into two separate circuits, one for the sockets and one for the cooking appliances - which is probably how it was originally.

 

[ban-all-sheds]

I wasn't far off with 24A haha it was a good guess.

YOU ARE A "FULLY QUALIFIED ELECTRICIAN" - YOU ARE NOT SUPPOSED TO JUST GUESS!

Why do words fail you detlefschmitz

Possibly because of the mistakes and dubious understanding of basic principles shown by the highlighted parts in this?:

The mcb is to protect the cable. The current carrying capacity of a 2.5 cable is 24A. The closest mcb size to that is 20A. If you linked the socket and the microwave with a 2.5 cable you have made it from a 2.5 to 5.0mm2. Do you know what I mean? The reason a ring main can go on a 32A is because it is 2 x 2.5 cables making it 5mm2 in total. Because it's been split to single 2.5s it can only carry 24A maximum. So yes it needs to go on a 20A unless you put a 2.5 to link the two cables. With the loadings you have statd the cable isn't going to be overloaded and is fine. But I'd put a 20A mcb in then the circuit is covered

 

[Michaelsf90]

I know 2.5 is a 20A maximum when it's own. That's the most important thing. Yes i could look up the exact Amps in the regs book but I know it can't go on a breaker on its own over 20A so why do I need to look when that's fact? No fully qualified electrician knows every single regulation off by heart

 

[AndyPRK]

You think you know facts but I think they the wrong!

 

[EFLImpudence]

I know 2.5 is a 20A maximum when it's own.

No, it isn't.

That's the most important thing.

No, it isn't.

Yes i could look up the exact Amps in the regs book but I know it can't go on a breaker on its own over 20A

Yes it can.

so why do I need to look when that's fact?

Errr - because it isn't?

No fully qualified electrician knows every single regulation off by heart

Very true - but the maximum CCC of the cable most commonly used for one of the most commonly inatalled circuits in domestic installations???

Apart from which, you were told yesterday.

 

[Michaelsf90]

So what mcb would you put a single 2.5 on?

 

[Michaelsf90]

And I don't do domestic installations. Industrial/commercial