After demand diversity

[Ian1981]

Does anyone know the working method the supply companies use to calculate after demand diversity.
Most new houses are supplied with 100amp fuses in the cut out.
Now obviously the average houses don't come anywhere near using that amount of current, however the DNO must allow a working average current for each phase.
The iet design guide gives a little insight but wanted to know other people's thoughts.

 

[westward10]

A colleague used to do design and he told me for a housing estate you would allow 6A per dwelling but that was about 15 years ago.

 

[Ian1981]

A colleague used to do design and he told me for a housing estate you would allow 6A per dwelling but that was about 15 years ago.

6amps seams really really low.
We've got 14 flats on a floor and we are fitting a bemco to each floor 6 in total.
16mm swa has been specked to each flat and 40 amps per flat which is really generous as each flat is only 1 bedroom and only have 2x 1.5kw heaters in and an immersion.
I'd say more like 20 at the most.

 

[westward10]

It was a while back but it must have worked.

 

[Wilko]

Hi - here's some After Diversity Maximum Demand numbers from a DNO design spec, just FYI.

 

[Ian1981]

I'll come up with a design with my boss and speek to the DNO and consultant about requirements.
At the end of the day I don't want to be pulling in unnecessary large cables.

 

[Ian1981]

Hi - here's some After Diversity Maximum Demand numbers from a DNO design spec, just FYI.

View attachment 36537

Thanks wilko will have a look

 

[chris day]

Thanks wilko will have a look

Keep us posted on your findings as I have also wandered how to apply for diversity on flat sub mains