# kva

#### k3v1n

any help would be grateful

I am turning a house into 4 flats

I am going to need 4 x100 amp supplys as I am having electric showers cookers, storage heaters ect

the supply company has asked what kva I will need, but im not sure

#### DetlefSchmitz

Well, I have no idea about the politics of this. But you say each supply needs to be 100A. That is equivalent to 230 x 100 VA or 23kVA.

#### k3v1n

I am going to need 80/100 amp supply to each flat and I only have 1 supply at present, and they have asked me what kva I will need
I am not sure so any help or advice would be much appreciated

thanks

#### JohnW2

I am going to need 80/100 amp supply to each flat and I only have 1 supply at present, and they have asked me what kva I will need
Make sure you are sitting down when they start talking about cost!

Kind Regards, John

#### EFLImpudence

Most flats and a lot of houses manage with 60A supplies.

Is there a gas supply to the premises?

Edit - Sorry, I suppose not with storage heaters.

#### k3v1n

no gas in property

the flats are not very big either, would you recommend 60 amp supplys?

what would be the total kva for 4 flats?

#### Astra99

Multiply the number of amps by 230 and then divide by 1000. This will give the KVA (kilo-volt-amps) which, if the Power Factor is Unity is the same as KiloWatts

#### winston1

Multiply the number of amps by 230 and then divide by 1000. This will give the KVA (kilo-volt-amps) which, if the Power Factor is Unity is the same as KiloWatts

Better still multiply by 240 as that is the actual voltage you will get.

#### ericmark

I would say the off peak supply is the major thing. With off peak although using electric for shower it would not be of the instant type as you would want to use the off peak power.

So add together the heaters and immersion heater and add a little bit as these will all come on together for an extended time. Remember any tumble drier or washing machine also programmed to switch on to take advantage of cheap rate. Storage heaters come is different sizes from 0.85kW to 3.4kW immersion heater normally 3kW with a house there may be many heaters and easy to hit the 100A limit with a flat however not so likely in the old days we had a separate consumer unit for storage heaters but today often the timer is in the heater rather than on the supply.

Economy 7 is a tariff not a system with some today there is a boost during the day clearly this will likely increase to power used as cooker could be on at same time as heaters.

I would not expect a problem with 60A fuse but the whole reason why the DNO ask is the only person who knows what is being fitted is the owner.

#### JohnW2

Storage heaters come is different sizes from 0.85kW to 3.4kW immersion heater normally 3kW with a house there may be many heaters and easy to hit the 100A limit with a flat however not so likely
Is this not a point which is being largely overlooked in this discussion? The fact that a building is going to be changed from one dwelling to four dwellings does not mean that the total heating requirement (for the whole building) is suddenly going to increase 4-fold, or anything like that. I would therefore suspect that the amount of electricity per flat required for heating is probably less than some might imagine.

Kind Regards, John

#### AndyPRK

I doubt you are going to need a 100A supply per flat .

I guess the concern is that there will be 3 more cookers, showers, immersions and that they are likely to be on at the same times.

#### JohnW2

I doubt you are going to need a 100A supply per flat . ... I guess the concern is that there will be 3 more cookers, showers, immersions and that they are likely to be on at the same times.
Indeed - and of all that, I would think that its the four showers, quite possibly sometimes being used simultaneously, which is likely to be the biggest issue.

Kind Regards, John

#### k3v1n

so if I need 4 x 60 amp supplys do I calculate the following

60x4 =240x230 then divide by 1000= 55.2kva

is that correct?

/

#### DetlefSchmitz

It's right. But as I understand it they will want to know the number for each supply, not for the total.

It begs the question whether you want 4 separate supplies (so that each flat pays their own bills and defaults are not your worry), or one metered supply with 4 private meters, in which case you have to collect the payments, but there are 3 less standing charges.

There are other possibilities and I'm not an expert.

#### Monkeh

Multiply the number of amps by 230 and then divide by 1000. This will give the KVA (kilo-volt-amps) which, if the Power Factor is Unity is the same as KiloWatts

Better still multiply by 240 as that is the actual voltage you will get.

Amusing assumption.

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