Consumer Unit Question

[Londoner2]

Hiya ,

Had a one off occur in my kitchen extension, we had the plugs trip due to many plugged in appliances being operated at the same time, it has never happened before, it was installed in nov 2019.

The MCB is rated at 16a hence it tripped, so can i replace it with at 32a with the current setup although it says not to exceed the rated 63amps bearing in mind diversity or is it best to replace the consumer unit with a larger one?

 

[EFLImpudence]

, so can i replace it with at 32a with the current setup

Not without knowing the size of the cable and installation method (through any thermal insulation?).

Do you have a Electrical Installation Certificate for the kitchen?

 

[Londoner2]

Not without knowing the size of the cable and installation method (through any thermal insulation?).

Do you have a Electrical Installation Certificate for the kitchen?

Yes, it says 2.5mm for cooker, 1.5mm for sockets n 1mm for lights

 

[ericmark]

Sockets can be wired as a ring final or a radial, and with a ring final the cable must be rated over 20 amp throughout its length, with a radial it can be far less, 2.5 mm² is not a single rating, but depends on how it is run, surface, buried, etc.

One can have a 6 mm² radial, but unlikely, we never supply at more than 32 amp, but as seen can be down to 16 amp.

I look at my kitchen, the cooker is on its own circuit, so kettles, dishwasher, air fryer, etc, but they do not tend to all run together, so unless non kitchen appliances are put in the kitchen, I have seen things like washing machines and tumble driers put in a kitchen, and food and dirty linen do not really mix, but the regulation's appendix says fixed appliances over 2 kW should have a dedicate circuit, but we know that is not going to happen, but can't run laundry and kitchen at the same time, and not expect it to trip.

At 1.5 mm² for sockets, 16 amp is your maximum.

 

[Jurassicspark]

Yes, it says 2.5mm for cooker, 1.5mm for sockets n 1mm for lights

If the cable is clipped to a surface or buried in masonry then 1.5mm can only carry up to 20A.

What you propose of changing the MCB to a 32A will not be allowed.

You can either swap the 1.5mm for a 6mm cable with upgrading the MCB or convert the circuit to a ring. You'll be then able to consume 32A from that circuit supplied from a 32A or 27A MCB.

 

[Londoner2]

hiya,

Let me update :

 

[Londoner2]

Sockets can be wired as a ring final or a radial, and with a ring final the cable must be rated over 20 amp throughout its length, with a radial it can be far less, 2.5 mm² is not a single rating, but depends on how it is run, surface, buried, etc.

One can have a 6 mm² radial, but unlikely, we never supply at more than 32 amp, but as seen can be down to 16 amp.

I look at my kitchen, the cooker is on its own circuit, so kettles, dishwasher, air fryer, etc, but they do not tend to all run together, so unless non kitchen appliances are put in the kitchen, I have seen things like washing machines and tumble driers put in a kitchen, and food and dirty linen do not really mix, but the regulation's appendix says fixed appliances over 2 kW should have a dedicate circuit, but we know that is not going to happen, but can't run laundry and kitchen at the same time, and not expect it to trip.

At 1.5 mm² for sockets, 16 amp is your maximum.

 

[Taylortwocities]

Need to see the other columns on the test sheet.

 

[Londoner2]

Need to see the other columns on the test sheet.

 

[Murdochcat]

On the face of those figures it appears to be a ring so upgrading the mcb to z32A is feasible.

Get a spark to verify the figures when they do the work

 

[ericmark]

This seems to show it is a ring. What is the supply to the consumer unit?

 

[Taylortwocities]

On the face of those figures it appears to be a ring so upgrading the mcb to z32A is feasible.

Get a spark to verify the figures when they do the work

Agreed. A competent person must confirm that the circuit is actually a ring. A ring final, with that cable size, would normally have a 32amp MCB. We have to ask why there was only a 16amp MCB fitted.
Usually that is because there is a lack of continuity of the ring. In that case the usual solution (rather than to go to the effort of finding the problem!) is to just install a 16amp MCB.

 

[Londoner2]

Agreed. A competent person must confirm that the circuit is actually a ring. A ring final, with that cable size, would normally have a 32amp MCB. We have to ask why there was only a 16amp MCB fitted.
Usually that is because there is a lack of continuity of the ring. In that case the usual solution (rather than to go to the effort of finding the problem!) is to just install a 16amp MCB.

The reason why is because my main CU is a wylex one n thats full, the builders electrician just installed the axiom one.

 

[Londoner2]

View attachment 375244 This seems to show it is a ring. What is the supply to the consumer unit?

100 amp