Will you check over my calculations

[Gazthesparky]

Hi Guys

I would appreciate someone just casting their eyes over my calculations.

I carnt decided what to do I'm doing a kitchen renovation and existing 6mm 32a supply but I don't know whether to upgrade to 10mm and 40a breaker as the volex unit doesn't do a 45a

Diversity comes out at 22amps but I'm not sure what to do ?? Any advice as its a double oven and Hob total of 50amps

5100w double oven 22.17 amps

6400w Hob 27.83 amps

50amps total

Diversity
First 10 amps

Then 30% of the remainder so (40amps)

30x40= 1200

1200\ 100= 12 amps

10+12= 22 amps with diversity so a 32a 6mm supply is ok

My gut feeling is upgrade to 10mm and 40a breaker

What's people's thoughts ?

Cheers

 

[telectrix]

6mm and a 32A MCB. been good for 60 yearsfor cookers up to 15kW total load.your diversity calculations appear fine,assuming the cooker isolator does not have an integral socket outlet,and also assuming that the 6mm cable is not derated below 32A due to insulation.

 

[Gazthesparky]

6mm and a 32A MCB. been good for 60 yearsfor cookers up to 15kW total load.your diversity calculations appear fine,assuming the cooker isolator does not have an integral socket outlet,and also assuming that the 6mm cable is not derated below 32A due to insulation.

Wel it's a bungalow, so don't know how it's installed but guess there's insulation galore in the loft.

Just installing a single 40a cooker switch with no socket

Think that's ok even though in theory there's potential of 50a but with diversity it shouldn't hit that.

I use to work for a local council where rewiring houses where they required 10mm cooker circuits. So I guess that's where my thoughts are coming from

Might phone the manufactures tomorrow but does anyone know ?

The oven is a double oven at 5kw that's the total load but does the oven pull that at one time or is it split so you can never pull the 5kw

 

[Andy78]

I would always double check my workings out and cross reference them with the manufacturer's recommendations when installing multiple cooking appliances to the same circuit.

You can apply diversity how you like, as you have, or perform the same calc for each appliance and add them, or just apply a percentage of total full load. It's up to you and your experience and the information given.

I have come across a few cheap hobs and ovens that feature no cycling nature across the individual parts of the appliance and can draw their stated full load at any one time and for a sustained time.