Cable size for kitchen ring?

[Extrasolar]

I'm rewiring the kitchen next week and am thinking that 2.5mm cable is too small. Appliances running will be, although maybe not all at the same time:

Kettle - 3000w
toaster - 1000w
fridge / freezer - don't know but I suppose the average.
freezer - don't know but I suppose the average.
Microwave - 600w although thinking of getting more powerful one.
Washing machine - don't know. it's about 2 years old.
Tumble drier - don't know. it's about 5 years old.

I'm thinking 4.0mm but I don't know wether to go for 6.0mm. Should I assume that all appliances will be running at the same time?

What is the average cable size to be installed in kitchens?

 

[il78]

Are you thinking about installing a radial?

Circuit will be fine as a ringmain wired in 2.5mm

 

[Extrasolar]

I was thinking a ring circuit. What about radial for curiosity?

 

[Big_Spark]

Extra Solar, please don't take this the wrong way, but if you do not know the answer to this question, then I must question whether you are competent to undertake the work.

 

[il78]

There's nothing wrong with radials as the over-current protective device kicks in if any problems.

Sorry writing disappeared.

But it needs to be designed to suit your requirements.

 

[BR]

2.5mmsq is the standard size cable for use in all ring circuits throughout the house. Is it possible to wire the circuit with 6sq and protect with a 40A MCB? In Ireland it is not. ETCI regs do not allow more than a 25A breaker protecting 2.5sq (20A in practice). Perhaps someone can clarify the IEE's view of this.

In answer to your question, it is generally not assumed that all appliances will be operating together and a 32A RCD protected 2.5sq ring is quite sufficient. If it were a commercial or industrial insulation the issue would be overcome by installing two rings.

 

[Big_Spark]

BR, it is normal ofr a ring to be protected by a 32A device, whether it be a BS1361 fuse, MCB or RCBO.

In Commercial and Industrial situations it is normal to wire the ring in 4mmsq cable due to the hgiher average use they will be expected to have at any one time.

Wiring a ring in 6mmsq is not practical, nor cost effective.

 

[BR]

Socket circuits in industrial installations in ireland MUST by ETCI regs be wired using 6sq and protected with a 32A MCB.
The point i was making is that commercial/industrial installations are generally designed to cater for the maximum load (within reason) likely to be placed upon them, domestic are not.

My question was: In Ireland it is not permissible to protect a ring main with a 32A protective device as it is in Britain. Neither is using 6sq (or 4sq) and protecting it with a higher rated MCB "where socket outlets of a lesser rating than the rating of the protective device exist".

Bottom line: 2.5mmsq cable may never be protected with a larger protective device than 25A regardless of whether the circuit is ring or radial

Is it compliant in britain to (just for arguments sake) wire a socket ring in 6sq and protect it with a 40A MCB/RCD

 

[Extrasolar]

I am competent enough to undertake the work as I've rewired the rest of the house fine. I just wasn't sure wether I would need 2.5mm or 4.0mm cable in the kitchen. If I could find out what is the standard used by qualified electricians then I would be better informed.

If the kettle and toaster are on at the same time then 4000W is being consumed at 17A. With everything else I'd be pretty close to the 20A breaker's max.

 

[Big_Spark]

I am competent enough to undertake the work as I've rewired the rest of the house fine. I just wasn't sure wether I would need 2.5mm or 4.0mm cable in the kitchen. If I could find out what is the standard used by qualified electricians then I would be better informed.

If the kettle and toaster are on at the same time then 4000W is being consumed at 17A. With everything else I'd be pretty close to the 20A breaker's max.

Why would you put the ring on a 20A breaker?

 

[Extrasolar]

I am competent enough to undertake the work as I've rewired the rest of the house fine. I just wasn't sure wether I would need 2.5mm or 4.0mm cable in the kitchen. If I could find out what is the standard used by qualified electricians then I would be better informed.

If the kettle and toaster are on at the same time then 4000W is being consumed at 17A. With everything else I'd be pretty close to the 20A breaker's max.

Why would you put the ring on a 20A breaker?

Aye, It'd be on a 32A breaker not 20A. Was havin' an online convo about something else and it crept in here. Sorry.

 

[Big_Spark]

No problem, at least you said 20A not 40A!!

Afterall, the circuit would certainly be safer on a 20A, but it might be a little problematic on occasion.

I would advocate the Kitchen ring going on an RCB though as oppose to a standard MCB.

32A 30mA should be OK, although if you have an old fridge/freezer, more than about 4 years old, then I would make it 32A 100mA to avoid nuisance tripping.

This is simply due to manufacture of the item in question, the way that the compressors switched on the older units could sometime cause RCD's and RCBO's to trip without a real fault being present if they only had a 30mA rating. Newer machines do not tend to cause this problem unless they are the cheaper brands.

 

[paulh53]

BR, it is normal ofr a ring to be protected by a 32A device, whether it be a BS1361 fuse, MCB or RCBO.

In Commercial and Industrial situations it is normal to wire the ring in 4mmsq cable due to the hgiher average use they will be expected to have at any one time.

Wiring a ring in 6mmsq is not practical, nor cost effective.

Domestic Ring Circuits Are Wired With 4mm2 T+E Cable If They Are Protected By a BS 3036 (Rewirable Fuse),

 

[Extrasolar]

BR, it is normal ofr a ring to be protected by a 32A device, whether it be a BS1361 fuse, MCB or RCBO.

In Commercial and Industrial situations it is normal to wire the ring in 4mmsq cable due to the hgiher average use they will be expected to have at any one time.

Wiring a ring in 6mmsq is not practical, nor cost effective.

Domestic Ring Circuits Are Wired With 4mm2 T+E Cable If They Are Protected By a BS 3036 (Rewirable Fuse),

That was the case with mine but it was old (20 years+). I have replaced it with 2.5mm2 T+E on a 32A breaker.

 

[paulh53]

That was the case with mine but it was old (20 years+). I have replaced it with 2.5mm2 T+E on a 32A breaker.

I Recently Rewired An Arcade Using 4mm2 T+E Cable On Each 32a Ring Circuit Simply Because Of The Length & Loading Of Each Circuit, Even Though Each Circuit Covered An Area Of Less Than 60m2
It Was To Keep The "Volt Drop" To Within Tolerances,