Uncertainty over cable size

[John Love]

What is the correct cable size on a radial circuit to feed kitchen sockets, except for the cooker,on a 32 amp fuse?

 

[Octopus]

Is this a college question?

What do you think?

 

[Andy78]

The correct size of cable would depend on the arrangement of the circuit and the installation method of the cable along with other derating factors and considerations towards prospective earth fault loop impedance values and volt drop.

 

[Pete999]

What is the correct cable size on a radial circuit to feed kitchen sockets, except for the cooker,on a 32 amp fuse?

How long is the circuit
Installation method
Appendix 15 BS 7671

 

[John Love]

The correct size of cable would depend on the arrangement of the circuit and the installation method of the cable along with other derating factors and considerations towards prospective earth fault loop impedance values and volt drop.

Thank you for responding .

 

[Deleted member 26818]

If the protective device is 32A, then the CCC (Current Carrying Capacity) of the cable has to be higher.
The CCC will depend on the installation method, but generally you would use 4mm2 or perhaps if the cable runs through a lot of insulation, 6mm2.

 

[John Love]

Thanks.That is really helpful.

 

[John Love]

Is this a college question?

What do you think?

Not a college question.
Installation was done in 2.5. and passed as being safe.
Recent problem and Home Emergency electrician informed me that it should not have passed and should be in 4mm.

 

[Andy78]

Not a college question.
Installation was done in 2.5. and passed as being safe.
Recent problem and Home Emergency electrician informed me that it should not have passed and should be in 4mm.

If it is wired in 2.5mm cable as a ring circuit then it is (most likely in a typical domestic installation) fine on a 32A mcb. As a radial then no.

 

[John Love]

Thanks.It is on a radial.

 

[Taylortwocities]

Not a college question.
Installation was done in 2.5. and passed as being safe.
Recent problem and Home Emergency electrician informed me that it should not have passed and should be in 4mm.

Who 'passed' it?
The Home Emergency guy is right.
There are two solutions
1. Rip out the cable and replace it with 4mm
2. Change the MCB to 20amp, or a 25amp if you can find one for your make of consumer unit.


My above reply does depend on some basic inforomation as asked by Pete

How long is the circuit
Installation method
Appendix 15 BS 7671

 

[John Love]

The area the area of the kitchen is approx 30 metres.
The radial circuit was installed around the perimeter of the kitchen before the kitchen was fitted and appliances installed.

 

[John Love]

How long is the circuit
Installation method
Appendix 15 BS 7671

The area of the kitchen is approx 30 metres.
The cabling was installed in the perimeter wall before plastering was done.

 

[Taylortwocities]

So you’ll have to limit the current to the current carrying capacity of the cable. And that is somewhat less than 32amps.
Replace 32A MCB with a 20 or 25A MCB.

The alternate is to find the socket at the end of the radial and run a length of 2.5mm from there to the consumer unit. Then the radial becomes a ring final and ok for the 32amp MCB (subject to testing).

 

[John Love]

Thank you very much for taking the time to respond and giving me the possible solutions.Much appreciated.

 

[telectrix]

my first action wouyld be to replace the MCB with a20A or 25Aas previously suggested. cheapest , easiest option. if it trips, then conversion to a 32A ring would be next step.

 

[Spoon]

I may get shot down for this but seeing that its a kitchen feed I would feel it better to keep it at 32A and make it into a ring.
Any other room I'd say change the breaker to a 20A.

 

[Octopus]

Not a college question.
Installation was done in 2.5. and passed as being safe.
Recent problem and Home Emergency electrician informed me that it should not have passed and should be in 4mm.

I'm hoping you have the certificate and the details of the installer - and if you do you need to address your concerns in writing.

As its a kitchen I'm guessing you have multiple appliances on said circuit and therefore you really do need to get this sorted out before something starts smelling of burning.

 

[John Love]

Thanks,I have the paperwork and hope to have this resolved amicably. Having clear responses from the forum has clarified the issues for me.Cheers.

 

[John Love]

Thanks.Good idea if it can be done without having visible cable.