Maximum Wattage

[spx]

Hi guys could anyone advise on the maximum allowed current on 2.5mm wire please.

My mother has one oven in her kitchen at the moment but would like to install another one. The circuit the oven is on is bestoke to the kitchen but is only 2.5mm. it has a 32amp breaker.

The ovens will be no more than 2.5kw each but I concerned that there are other appliences on this circuit aswell ie washing machine, fridge, microwave and kettle. Please advise if it would be ok to add this second oven or would "I" need to put a 4mm radial circuit in. If so what size breaker would you use, still 32amp?

 

[davy_owen_88]

Can you confirm the 2.5mm² circuit you are talking about is a ring circuit not a radial.

2x ovens will be drawing about 20A so I would install a new circuit. 4mm² at a minimum but it might be worth installing larger in case your mum decides to get an electric hob at a later date.

32A MCB is fine for 4mm² t&e assuming certain factors are dealt with.

This work is notifiable.

 

[ricicle]

A 2.5mm² radial should not be on a 32 A MCB which, as I understand, you have at the moment.

EDIT:Sorry Davy, missed your first line

 

[spx]

Hi,

The current set up is 2.5mm ring circuit 32amp.

This work is notifiable.

I know, that part P is a bu**er. My authority doesn't accept self certification.. they insist on a qualified electrition installation.

 

[RF Lighting]

It depends on how the cable is installed as to how much current it can safely carry.

Even installed in the best conditions 2.5mm² T&E cable is not able to carry 32A, so the MCB currently protecting the cable is too large.

The next size down from a 32A MCB is a 20A, which will allow you a maximum load of 4.6kW, so this cable is not big enough for the ovens on there own, never mind the other appliances on the circuit. (This is assuming the cable is installed in a non insulated wall, where its safe CCC drops to 18.5A)

The best thing to do in my opinion is to install a new seperate 2.5mm² radial for each oven, or a 6.0mm² radial for both ovens


If you intend to do this work yourself are you aware this work will require notification the your LABC?

 

[davy_owen_88]

I know, that part P is a bu**er. My authority doesn't accept self certification.. they insist on a qualified electrition installation.

Only a qualified electrician who is a member of a self certification scheme can 'self certify' but they must allow you to do the work yourself if you pay their fee and then they should do the inspecting and issue the BC cert.

 

[RF Lighting]

I've now seen you have a ring circuit, which makes a difference to the CCC of the cable, but bearing in mind you already have a washing machine, fridge, microwave and kettle etc connected to the circuit, then I would say you still really ought to install a seperate circuit(s) for the ovens

 

[plugwash]

I know, that part P is a bu**er. My authority doesn't accept self certification.. they insist on a qualified electrition installation.

Only a qualified electrician who is a member of a self certification scheme can 'self certify' but they must allow you to do the work yourself if you pay their fee and then they should do the inspecting and issue the BC cert.

but if they won't then short of taking them to court which will be a huge waste of time and money what can you do about it?