max demand for 12x all elec flats

J.C.E · Sep 17, 2018

starting 12x flats next week that will be all elec -with a rather juicy electric boiler (12kw)- havn't won the intake/communal work yet- but just doing my pricing for it ready

does my maths look good for working out the max demand and kva of main supply- currently it is only 100a TPN so around 73kva right? (it was a office before) builder knows with these juicy boilers the main incoming needs ugrading.

am i right in thinking becuase the main head will need to be bigger than 200a TPN (315a TPN) will it need a CT chamber?

what is the CT chamber actually for? and any recommendations of a good one to use

cheers
J

[ElectriciansForums.net] max demand for 12x all elec flats

Strima · Sep 17, 2018

Rings probably around 5 amps each, the odd surge when the kettle goes on etc.

Lighting and smokes around 2 amps, even less if only a few LEDs.

I'd drop a bit off the hob and oven as well as once warmed up they'll start to cycle and not draw too much.

TJ Anderson · Sep 17, 2018

J.C.E said:
starting 12x flats next week that will be all elec -with a rather juicy electric boiler (12kw)- havn't won the intake/communal work yet- but just doing my pricing for it ready

does my maths look good for working out the max demand and kva of main supply- currently it is only 100a TPN so around 73kva right? (it was a office before) builder knows with these juicy boilers the main incoming needs ugrading.

am i right in thinking becuase the main head will need to be bigger than 200a TPN (300a TPN) will it need a CT chamber?

what is the CT chamber actually for? and any recommendations of a good one to use

cheers
J

View attachment 44351

Hi

Have you got your Diversity calcs for getting to 74A per flat?

Also, why are you not having 13 metered supplies from DNO?

J.C.E · Sep 17, 2018

TJ Anderson said:
Hi

Have you got your Diversity calcs for getting to 74A per flat?

Also, why are you not having 13 metered supplies from DNO?

ryefeild >>12x meters>> 12 isoaltors

but will there need to be CT before the ryefeild?

J.C.E · Sep 17, 2018

Strima said:
Rings probably around 5 amps each, the odd surge when the kettle goes on etc.

Lighting and smokes around 2 amps, even less if only a few LEDs.

I'd drop a bit off the hob and oven as well as once warmed up they'll start to cycle and not draw too much.

just rule of thumbed total of mcb x 0.4

TJ Anderson · Sep 17, 2018

You would need to consult with DNO on that as you want individual metered supplies. One for each flat and one for landlord areas.

The CT chamber is so the DNO can mount a meter on the front and put current transformers around the phases to meter larger supplies ( >100A). That's not what you want though.

Leesparkykent · Sep 17, 2018

No CT chamber needed. Head, isolator, rye field, meters, switch fuses.

J.C.E · Sep 17, 2018

TJ Anderson said:
You would need to consult with DNO on that as you want individual metered supplies. One for each flat and one for landlord areas.

The CT chamber is so the DNO can mount a meter on the front and put current transformers around the phases to meter larger supplies ( >100A). That's not what you want though.

so ct just needed if a big supply is only to be metered by one meter rather than split into multiple meters (flats)