Cooker mcb problem

I will know for next time that it is not the R or D...as you can tell I'm not an electrician. In your opinion the cable in the photograph what size do you think it is?
I'm rather annoyed because the electrician I used was someone I used on a regular basis and if he fitted an incorrect rated cable I will not be happy. The electrician I used a few weeks ago to hard wire some smoke detectors I mentioned to him that we might need a bigger cable and he said not necessarily ill just fit a 42amp breaker????
What's going on, aren't you electricians supposed to be singing from the same hymn sheet....
 
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If that cable has been fitted recently then get him back, and before he arrives asking him to do some reading up on permitted safe zones!
No such thing as a 42A breaker, the lesser the CSA of cable the lesser the rating of the breaker, not the otherway round, you must have misunderstood/misheard.
 
Going back to the beginning -
How did you calculate the 33A you stated? This will not trip a 32A MCB.


As you admit, you are not an electrician - no problem there - but there are some inaccuracies in your questions which make it really difficult to all answer with consistency.
 
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I will do. I have just checked the sizes, can you confirm that a 2.5mm cable has one strand of copper wire and 4mm cable has several strands of copper wire?
 
I worked out the calcs using the total W of 4 hobs and the oven then divided it by the Voltage to get the amps....
 
Fair enough, then it should not trip the breaker.

Perhaps the breaker is getting a bit 'weak'.
 
Before, about a year and a half ago we had an electric oven and gas hob. The oven was run on 13amp. We bought a new cooker at 12.7 kw with everything on - 5 ceramic hobs, grill, 2 ovens and a hot plate. The electrician I use came and wired it in. No questions were asked, about output of cooker. I then said to a different electrician about size of cable and he said ill just fit a 42amp breaker, which he still not done....
 
I will do. I have just checked the sizes, can you confirm that a 2.5mm cable has one strand of copper wire and 4mm cable has several strands of copper wire?
If this is new cable 2.5mm would be solid and 4.00mm cable will be stranded both will have a solid earth/CPC core.
 
Yup...the cable is 4mm.
Any particular reason for the tripping mcb.
Is there any significance with burn mark on the neutral side....upon opening CU there were 2 not loose loose connections but were not tightly screwed in and neat...
 
I think that now it has calmed down, that it could be possible that it had contributed towards it.
But as previously mentioned if that cable is recently installed, it looks to me that it does not comply to the permitted safe zones and the installer should be asked back to install correctly and also mention loose connection at the board. I assume you have a certificate for this work?
 
Yes,,,cert obtained. I have a basic understanding of the safe zones. In what way does it not comply...
 
We bought a new cooker at 12.7 kw with everything on - 5 ceramic hobs, grill, 2 ovens and a hot plate. The electrician I use came and wired it in. No questions were asked, about output of cooker. I then said to a different electrician about size of cable and he said ill just fit a 42amp breaker, which he still not done....

12.7kw on full load will require 55.22A, this would in simple terms require 10mm cable and a 60A type B (which you don't come across)
But fortunately we can calculate diversity to this appliance and 15kW of power can be run from a 32A circuit, although 6.00mm is the more common selected cable, 4.00mm will carry 37A providing there are no de-rating factor to calculate to the design of the circuit. The method of installation and the fabric the cable is and/or contained in along it's route, would be part of this calculation. So it is quite easy for 37A cable to be dramatically de-rated and must be protected be a device equal or less than that final value.
If the demand of the circuit is at such a level that a lower rated device would not be suitable for the demand, then the cable size must be increased.
It is nonsense to suggest and increased breaker size to be introduced without accessing the demand and cable sizing.
42A device do not exist. This sounds and looks like a DIY job.
 

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