electric oven & hob allowing for diversity

[mbelectric]

I was working with an electrician with 30 years experience today. We came across a cooker switch which was fed from the cu with 6mm t&e.
From the switch there was a 2.5 t&e to the 5kw electric oven and a 6mm t&e to the 6kw electric hob. By my calculation there would be a total of 48 amps but with diversity this is reduced to 21 amps so the 6mm should be fine. He told the customer that the 2.5mm needed to be replaced with 6mm or fused down and I am not sure this is correct. If you apply diversity to each individual cable coming out of the switch then the 2.5mm and 6mm will be ok. Am I correct in this assumption or is he correct? BTW this electrician is ALWAYS right so I just agree with him at the time then try and get the correct answer from here.

 

[GaryMo]

Has the 2.5mm t&e got suitable overload protection?

 

[mbelectric]

There is a 40amp mcb at the cu. From there, a 6mm cable goes to a cooker switch. From the cooker switch there is a 6mm to the hob and a and 2.5mm to the oven.

 

[GaryMo]

So no overload protection for the 2.5mm t&e then.

 

[JohnD]

IMO the diversity rules for cookers are a bit on the low side.

When you are cooking Christmas dinner for the family you will have all rings and ovens going, possibly all turned on from cold at about the same time.

 

[mbelectric]

Doh !

I said he was always right didn't I !!!!!

Thanks Gary.

 

[mbelectric]

Agreed John, but you can do most of Aunt Bessie's in the Microwave now.

 

[securespark]

Most of Aunt Bessie's what??