Discuss New electric supply - ADMDs in kVA - kVA load required in the Electrical Forum area at ElectriciansForums.net

Peter1981

EF Member
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6
Location
London
Hi

I'm applying for a new electric supply.
UK Power Networks have requested an accurate breakdown of the "required kVA load".
ALL ELECTRIC 2 BED FLAT.

I have worked out my requirements as below in watts, but am struggling to convert to the "ADMDs in kVA" they require.

Lights: 280w
Sockets: 3200w
Hob/oven: 2500w
Shower: 10000w
Hot water instant boilers (2of) : 20000
Radiators : 14000

Total 61000w

What is the ADMD I require?
And
The kVA load required?

Tia
 

Rob

Control System Engineer
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Is my estimation over the top for an all electric 2 Bed Flat?

Surely there are all electric flats out there with reasonable consumption?
Diversity isn't a simple subject. I am presuming you aren't an electrician?

Diversity assumes that everything will not be working at maximum demand at the same time.

Would be worth while hiring someone to complete the design. Quite probably the electrical contractor you have in mind to install and test the installation would be able to perform this for you.
 
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Peter1981

EF Member
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6
Location
London
Diversity isn't a simple subject. I am presuming you aren't an electrician?

Diversity assumes that everything will not be working at maximum demand at the same time.

Would be worth while hiring someone to complete the design. Quite probably the electrical contractor you have in mind to install and test the installation would be able to perform this for you.
I'm a few months away for electrical works but am applying for a new supply due to the time it takes.

Does my estimation look out of the ordinary?
 

Rob

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Yes it does look rather high.

Without sitting down and doing some calculations, maybe this will give you an overview.

61kW is around 265amps @ 230V AC. The standard maximum supply fuse the network operators install for a domestic property is 100amp.

I know the average kva for a flat with gas heating is around 8kva.

The way you have calculated it gives approximately 61kva (PF of 1).
 
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Peter1981

EF Member
Messages
6
Location
London
Yes it does look rather high.

Without sitting down and doing some calculations, maybe this will give you an overview.

61kW is around 265amps @ 230V AC. The standard maximum supply fuse the network operators install for a domestic property is 100amp.

I know the average kva for a flat with gas heating is around 8kva.

The way you have calculated it gives approximately 61kva (PF of 1).
Thanks,
UK Power Networks have requested an accurate breakdown of the required kVA load.

If I send them my estimations they will probably advise an on site power station,
How should I breakdown my requirements?
 
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Wilko

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Berkshire
Hi - do you really need 14kW of electric heaters in a new build 2 br flat? I’m sure there will be advice on this topic from buildings folks (sorry don’t have a ref) but I’m thinking something like 1kW for each room say 5kW. Hob and oven 5kW. Water heating 10kW. Appliances 3kW. Total 23kW or 23kVA or 100A as per Tel :) .

You might consider having a small hot water tank with a 3kW heating element for use other than shower, say.
 

plugsandsparks

Electrician's Arms
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Location
Chesterfield
If it helps, anything up to 100A supply (23KVA) is bog standard. Anything over is not...eek.
You may have some heat loss calcs from your building regs / architect.
This will give you how much running current you need to keep it nice and warm. With modern builds you dont need a lot of KW to heat a place, lights take sod all and how many turkeys can you cook at the same time.
Tel has best answer.
My guesstimate would be
ADMD is 23KVA
Breakdown:
Shower 10KVA
Heating 8KVA
Turkey 1.8KVA
Lights 0.2 KVA
Forget the hot water instant boilers, thats insane.
Use a cylinder with immersion 3KVA
Or, use bottle gas for hot water and cooking
 

davesparks

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guildford
Lights: 280w
Sockets: 3200w
Hob/oven: 2500w
Shower: 10000w
Hot water instant boilers (2of) : 20000
Radiators : 14000

Total 61000w
Wow, what are you planning to grow in there that'll need keeping at tropical temperatures?
And 2x10kW water boilers? Are you going in to business making soup from whatever it is you're growing?
 
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Peter1981

EF Member
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6
Location
London
Hi - do you really need 14kW of electric heaters in a new build 2 br flat? I’m sure there will be advice on this topic from buildings folks (sorry don’t have a ref) but I’m thinking something like 1kW for each room say 5kW. Hob and oven 5kW. Water heating 10kW. Appliances 3kW. Total 23kW or 23kVA or 100A as per Tel :) .

You might consider having a small hot water tank with a 3kW heating element for use other than shower, say.
Thanks,
So hot water cylinder/tank is the way to go.

Hot water tank with heating element or unvented hot water tank?

Will the hot water tank supply 2 showers, 2 sinks & 2 basins?
 

telectrix

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hot water tank will be enough for normal showers, but if you have teenage daughters, get 4 10kW boilers.
 

Spoon

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Who needs electrical design engineers when you have a forum.
 

davesparks

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Thanks,
So hot water cylinder/tank is the way to go.

Hot water tank with heating element or unvented hot water tank?

Will the hot water tank supply 2 showers, 2 sinks & 2 basins?
They both have heating elements, but an unvented tank would be my personal preference as you get mains pressure hot water.
You will have to consult the person designing the plumbing installation to find out what size hot water cylinder is needed for the demand.
I think the biggest standard/commonly available size cylinder is 300litres, which I've seen installed for much bigger properties without a problem.
Even if you needed two cylinders in tandem you would still be cutting your power consumption as they are only 3kW each.
 

Megawatt

Regular EF Member
Messages
227
Location
NC. Gastonia
Hi

I'm applying for a new electric supply.
UK Power Networks have requested an accurate breakdown of the "required kVA load".
ALL ELECTRIC 2 BED FLAT.

I have worked out my requirements as below in watts, but am struggling to convert to the "ADMDs in kVA" they require.

Lights: 280w
Sockets: 3200w
Hob/oven: 2500w
Shower: 10000w
Hot water instant boilers (2of) : 20000
Radiators : 14000

Total 61000w

What is the ADMD I require?
And
The kVA load required?

Tia
Just tell power networks 70KVA, even knowing you are not going to draw that much amperage
 

Rob

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marconi

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Have you considered an air source heat pump which would provide room heating and cooling using less power/energy?

See:


and

 

Paignton pete

Regular EF Member
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Over the rainbow
The only way you are going to get what the energy companies require is to hire a electrical design company to do this for you.
Getting advice on a forum will only go so far especially if they are requesting a break down.

There is a lot of work involved in this.

There are many sparkies who have spent a lot of time and money training to do this.

Utilise there expertise.
 
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Rob

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Rob I don’t have money to burn but I like to all ways plan for the future
There is planing for the future but have to be practical.

The DNO wouldn't even entertain a 70kva supply for a 2 bed flat. Not when most even 3 - 5 bed houses only get a 23kva supply.

If they did, you would certainly be paying higher tariffs alongside a huge DNO installation bill.
 
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Megawatt

Regular EF Member
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227
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There is planing for the future but have to be practical.

The DNO wouldn't even entertain a 70kva supply for a 2 bed flat. Not when most even 3 - 5 bed houses only get a 23kva supply.

If they did, you would certainly be paying higher tariffs alongside a huge DNO installation bill.
I understand it’s just so different in UK than to US standers
 

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